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Harsh, unrelenting winter weather has continued bar an interlude last weekend when we had a few days of relatively fine, but still chilly weather. At least this gave all the keen fishos a chance t get out on the water.

Rapport has lain forlornly in her marina berth until we pulled her onto the hard stand early last week for her annual out of water check. We had noticed Rapport wasn’t pulling her full rpm – only reaching about 2,550 when she usually reaches about 2,800. In one sense this doesn’t matter as we normally onlycruise at around 1,600-1,800 rpm. However if a diesel engine doesn’t reach her designated WOT rpm it’s a sign of problems such as dirty hull and/or running gear, turbo issues or cooling issues in the case of an overheating engine. We weren’t running hot indicating that a fouled hull was the problem. Sure enough when we pulled Rapport out the hull was quite fouled, the props had a bit of growth and the shafts also had some growth and small mussels growing. Anti foul was last applied Feb ‘21 so we guess this is not surprising. New anti foul was applied plus Propspeed on the props and shafts. Also removed some fishing line tightly wrapped around both shafts near the props. This had to be burned off. Some paint imperfections in the cockpit also rectified.

Rapport was booked to be re-launched Thursday morning 18/8, however on the preceding Tuesday it was apparent we were in for a real blow so we delayed this a few days. Sure enough on Thursday there was a NE wind in the high 20 knots, gusting 40 with heavy rain. I’m glad we postponed.

Now all we need is some good boating weather or even half reasonable would be OK.

 How right were NIWA late last year when they forecast the 2021/22 North Island summer would be dominated by easterlieswith more gales, thunderstormsand wet weather than normally expected. We’ve lain at home in bed during quite a few nights in the last few weeks listening to wind and rain thankful to be ashore.There’s certainly been some nice sunny days, but on the water we’ve rarely had the settled predominantly south-west conditions we normally expect, the exceptions being a settled period in January before Cyclone Cody arrived and some nice periods in April. In fact we can rarely remember a period of such sustained south to north-easterlies occasionally tipping over into north-westerlies.

This significantly changes summer cruising dynamics, firstly because the east coast becomes exposed rather than sheltered and secondly because we’re all mainly used to anchoring for settled south-westerly conditionsrather than for strong easterlies.

Of course this has also opened some opportunities for cruising the normally exposedwest coasts of Great Barrier Island, Kawau Islandand Coromandel Peninsula, but you do have to get there and back safely and easterlies often bring large ocean swells and larger than usual wind-generated waves.

We last got out for 6 nights in mid-May anchoring around Onetangi including very pleasant Piemelon Bay on the east side of Onetangi when the wind went south-east.

Fortunately it’s nearly always possible to safely return home from the inner Hauraki Gulf islands, nearly all of which provide some secure anchorages during easterlies. Some of our favorites during E to NE winds areRakino Island’s West Bay, Waiheke Island’s Putiki Bay, Ponui Island’s Shark Bay and Rotoroa Island’s South-west Bay.

Anyway our Winter solstice is now only about three weeks away on 21 June and from there our dark mornings and evenings will very gradually lengthen out. Roll on settled SW conditions.

This is an edited version of an article I’ve written for Pacific PowerBoat magazine.

The public in general and the boating community in particular were stunned bythe tragic loss of five fishermen from the vessel Enchanter which capsizedoff Northland’s east coast onthe night of 20 March.

At this early stage many details are still not clear, butthey will surely emerge as investigations are carried out by the Transport Accident Investigation Committee, Maritime NZ, Police and possibly WorkSafe. However some information is availablefrom media reports, particularly from NZ Herald and Stuff.

Enchanter is one of three rugged vessels operated by Enchanter Fishing Charters, established by skipper Lance Goodhew in 1995 and who according to their website are“the Three Kings specialists”. She is a twin diesel engine powered 17 metrevessel designed by Erwin Hagg for deep sea fishing and constructed from glassed over double diagonal kauri with a displacement of about 30 tonne.She wason a five day fishing charter out of Mangonui to the Three Kings Islands, a group of 13 small islands located about 30nm NW of Cape Reinga in an area where the South Pacific Ocean meets the Tasman Sea. Despite their remoteness and reputation for strong currents and rapidly changingconditionsthe Kingsare regularly visited by fishermen and divers taking advantage of anabundance of fish lifefrom snapper to marlin. Overnight anchoring options are limited and regular visitors say that even a good night can be uncomfortable.

Enchanter is certified and skipper Lance Goodhew is qualified and highly experienced, reportedlyhavingspent 250 days each year at sea for the last 20 years. He withone deck hand and ten clients were already aboard Encounter at the Three Kings when a weather warning was issued by MetService on the morning of Saturday 19 March. Due to the reputation ofthe vessel and her skipper those aboardhad every reason to feel safe although one client, Mark Sanders,did mention reservations about the weather to his family prior to departure.

After some great fishingEnchanter headed back to the mainland on Sunday to complete her charter on schedule.Having owned, managed and skippered a 12 metre Oliver Royale charter vessel in the Hauraki Gulf myself some 15 years ago I can say there is some pressure to stick to the charter timetable because clients generally want to get home on time, a new charter awaits for which the vessel needs to be prepared, refueled and provisioned and there is often some maintenance to do.

Presumably the most challenging part of this trip would have been across the open waters between the Kings and the mainland, but Enchanter reached the mainland safely in early evening – Mark Sanders phoninghis wife around 1800hrswith no concerns expressed. As Enchanterpowered her waysouth towards overnight shelter she would have had the NE wind and breaking season her exposed port beam or port quarter. The tragedy unfolded when Enchanter activatedher two emergency beaconssouth of North Cape at about 2000hrs. It is believed the incident happened too quickly for any radio contact to take place.

Maritime NZ initiated a full response includingWhangarei’s Northland Helicopter Rescue, Auckland’s Westpac Rescue Helicopter, a RNZAF P3 Orion aircraft, the RNZN vessel Taupo and Houhara Coastguard. Two charter vessels over nighting at the Kings, Florence Nightingale and Katrina also left for the search area. Apparently some other local vessels also responded. After refueling in Kaitaia the Northland helicopter arrived on scene about 2340hrs. By the time fivesurvivors were located and rescuedin two groups near Murimotu Island, south of North Cape they had been in the water for about 4 hours. Apparently they had been located from lights visible in the water as they desperately clung on to a large pice of floating wreckage.The daring pilot with 30 years experience, Lance Donelly, reportsthere was a fierce storm in progress and that this was “the most extreme, most challengingrescue I’ve ever done”.

The remaining five were unable to be found and their bodies recovered later.

Cluesto Enchanter’s fate come from a survivor who had been in the cockpit at the time of the incident later reporting“nobody was to blame. It was a freak wave that came out of nowhere” and from Lance’s mother who reports her son told her they were hit by a gigantic wave over nine metres high. The wave’s force ripped off Enchanter’s flying bridge and capsized her.

Metservice estimates the wind would have been averaging 35 knotswith 2.5 metre waves at the time of the tragedy and if correct this hardly seems conditions that would cause many problems for a well found 17 metre vessel such as Enchanter, let alone rip her flying bridge off and capsize her. However Metservice’s assessment of conditions appears at oddswith those reported by thehelicopter pilot (fierce storm in progress) and by Florence Nightingale’s skipper who reports “absolutely horrendous” conditions with 55 knot winds. With such a wind out of the NE with a long fetch it is likely the waves would have been well in excess of 2.5 metres, quite possibly with average waves in the vicinity of four metres or more. However this is my opinion, not known fact.

NeverthelessMangonui Harbour Warden Steve Smith says “the Enchanter had been in similar conditions many times before with no issue ……. it has to be a freak accident.”

So the question is – is it feasible for a wave around a frightening size of nine metres to occur?

The answer is absolutely yes.

As wave trains roll across the oceans, the peak of one wave eventually synchronises with the peak of another, and the resulting wave can be much larger than either of the two waves that coincided.

The UK’s National Oceanography Centre determined that about one wave in 23 is twice the average height, one wave in 1,175 is three times the average and one wave in 300,000 is four times the average. Of course such waves are not only large but generate tremendous energy. Fortunately the largest of these monster waves are rarely encountered because they appear quite suddenly in a small area, possibly something like 50 to 100 metres long and lasting only a short time before dissipating.

Most marine tragedies result from a series of eventsand in this case they appear to be severe weather conditions, an unexpected large wave, darkness, heavy rain and spray causing poor visibility and remoteness from rescue resources.

How quickly time flies as I see it’s over 2 months since our last post detailing how we’d selected an ADC deck crane and Seafarer 3.4m RHIB. Meantime we’ve had nearly 3 weeks of cruising around the Waiheke / Ponui area since Christmas, selecting here due to the ease with which our kids and grandkids could join with us. Weather was mostly fine and sunny, though as seems common now the wind was up a bit. We caught plenty of fish and had a great time. Now we continue with the saga of  our new RHIB.

Bring on the power

My friend Frank and Iput Honda, Mercury, Suzuki, and Yamaha on our list of 15hp 4-stroke outboard power options. Over the years I’ve been a “Yamaha man”, but have also owned Honda and Suzuki while Frank has a lot of experience with Mercury and Suzuki, so we’re happy that any of these engines will meet our needsand turn our focus topoints of difference. While some dealers were very helpful we’refrustratedgetting good information from others.

Question: “can wehave a catalogshowing all the featuresandspecifications?”

Answer: “naa mate all that stuff is on the web these days”, or in one case “naa mate but there’s another dealer just up the road and he might have that stuff”.

Fact 1 – all of the manufacturers print expensive, comprehensive glossy brochures and spend a fortune on advertising.

Fact 2 – theymay be horrified to learn some of their dealers don’t have brochures available for seriousbuyers and in most cases make no effort to inform us about product features.

Fact 3 – yes most of the information is on the web, but have you tried printing it? And yes if I’m going to spend around$5,000 on a product I want a nice glossy brochure.

We finally get our brochures and start an analysis.

Dealer prices offered to us range from $4,895 for the Suzuki to $5,339 for the Honda, but we’re buying on features not price. Several dealers cite supply issues, but in reality all optionsareavailable if not immediately.

We build our spread sheet notingthat each brandhas some unique features,but become increasingly impressed with Suzuki:

-It’s several kilograms lighter than all other options and we feel this weight saving is significant aft ofthe RHIB’s transom where it counts (Suzuki advertise as being “lightest in class”).

–We prefer electronic fuel injection (EFI). Some dealers say this is a disadvantage citing reliability, but EFI was first introducedin 1987 (by Mercury)andin our view that’s long enough to be well proven.

–It has a unique Lean Burn Control System offering increased fuel economy (Suzuki claim an incredible 45 per cent).

–We like the non-start fresh water flushing system (which Yamaha also has).

With Suzuki also offering the lowest price we decide for this option.

Choosing our accessories

Chandlers supply storage covers and engine covers in various sizes and these are essential for protection against harmful ultra violet rays and the elements.

Seafarer fitted a set of Beachmaster pneumatic wheels plus two stainless steel rod holders. We also add a universal tiller extension.

Frank used his Quicksilver for expeditions and carried all his equipment aboard. Our Seafarer will primarily be used as a tender, sowe’ll only carry basic equipment of buoyancy vests, anchor, chain and warp, length of line for towing or other emergencies, orange safety square, bailer, sponge, telescopic boathook marked for depths, knife, inflation pump, basic first aid kit and spare kill switch. Secondarily we’ll use it for exploration or fishingexpeditions whenwe’ll carryadditionalsafety and other gear as appropriate, for example hand-held vhf, mini binoculars, air horn, water and snacks. We’ll also carry aboard Rapport a spare propeller (of a different pitch) with nut and split pin, sea water pump impeller, water pump kit, spark plugs and puncture repair kit.

The Suzuki didn’t arrive in time for our post Christmas cruise so we use a 6HP Mercury 4-stroke we had spare. This had enough power to plane with one aboard and almost plane with two. Since our return we have the Suzuki installed and look forward to trying it out. The Seafarer RHIB is great – plenty of room and very stable and dry.

Cruising update

It’s been great to get cruising again and with summer now underway this can only get better. 

It’s now official that La Nina weather conditions are expected this summer, bringing warmer than average sea and air temperatures (the seatemperature off Kawau is already 20.5d). The downside is La Nina also brings NE winds, increased rain and potentially some cyclonic conditions with the probability of increased thunderstorms. Thesecan be problematic due to sudden and sometimes severe wind direction shifts, so anchor with care to allow for this.

We’ve done two week-long cruises recently, one to the Ponui area and one to Mahurangi and Kawau.

Diane landed this monster 72cm snapper in 35 metres SE of Kawau

You can’t always get what you want

We’ve owned our 16 metreSalthouseSportFisher, Rapport, for two yearsnowand after 177nights aboard find her a capable and comfortable cruiser. But when you buy a pre-owned boat you inevitably make some compromises and a major one for us was not having a large RHIB. We really enjoy exploring areas around our anchorage and ideally wanted a RHIB at least three metres longwith a 15hp 4-stroke outboard and able to be lifted aboard usinga crane. Rapport came without a crane andwith an old Chinese built Takacatinflatable that we rubbished after a few weeks as it had toomany pontoon air leaks to be economically repaired. In any case we didn’t like the Takacat’s inflatable floor limiting movement in the RHIB.

It was December and we urgently needed a dinghy that two of us could easily lift onto ourforedeck cradle, sobought a new lightweight (33kg) Aquapro SLR 2.6m rigid-hulled inflatable andHonda 2.5hp 4-strokeair cooled outboard. We usedthe same outboard during our Med cruising years and found it very reliable and easy to start and lift.But for Rapport this was always a temporary solution and so aided by our best friend and long time boating companion, Frank, we started researching deck cranesand larger inflatables.

We knew this was going to be an expensive project and that making improvements to a boat doesn’t necessarily add value. Atrusted marine broker’s thoughts were that future potential buyers of Rapport would expect a vessel of this size to carry a substantial RHIB and crane, so adding these would increase her sales appeal and value. We didn’t need too much convincing and reassured byhis advice and the prospect of lots morefun ahead decided to proceed.

Finding a suitable crane

It would be possible to lift the new outboard fromthe RHIB using a simple transom-mounted hand-operated winch, unload the other gear and then pull the empty RHIB onto the foredeck by hand, but we’re getting a bit long in the tooth for that and want to be able to launch and retrievethe whole rigwith minimal effort.

The RHIB with its outboard, fuel and gear willweigh about 150kg so we need a24V DC powered crane with a safe working load of at least that. We find plenty of options for large cranes but few for smaller units.

Motor Yacht Services (MYS) are theNew Zealandagent for Brisbane-based Australian Davits and Cranes (ADC)and we find them very helpfulhaving fitted many ADCs with good results. MYS’s owner Dean Ryder checks Rapport and quotes $13,973 plus installation for their 350kgcapacity crane mounted on our starboard side with its standpipe passing through our master berth’s wardrobe down to the keel to support the load. Delivery was quoted as 8 weeks ex factory.

Oceanlift cranes are produced on a bespoke basis in Rotoruaand we find owner Mark Thomson also provides lots of information. Coincidentally the boat owner next to us in the marina is very happy with hisOceanlift. Mark visits Rapport andquotes $13,711 plus installation for his200kg capacitycrane with 6 weeks delivery.

Both units will suit us however the ADC’sadditional capacity will provide an extra safety margin, more future flexibility and enhancedresale value. These factorscombined with the fact that MYS install their ADC craneswhereas we need a separatecontractor to installthe Oceanlift lead us to choose ADC. We expect the installation to take around three days and to costto around $6-8,000.

Which RHIB will suit us best?

We’re looking for a rugged rigid-hulled RHIB about 3 metresin length with room for four adults,able to plane with at least two adults aboard using a 15hp outboard, with generous beam for lateral stability, a snub rather than pointed bow for greater internal space forward, a false flat deck for easier internal movement and to keep contents dry, a high bow to deflect spray, robust pontoons with three separate air compartments, paddles rather than oars and rowlocks,internal lifting points, rubbing strakes, storage for anchor and accessories and handles on the pontoons and bow. We’ll also fit top-of-the-line Beachmaster pneumatic wheels and two rod holders. We have a preference for a powder coatedalloy hull (being lighter and easier to repair), but will accept GRP all other things being equal.

We eliminate centre console optionsas in our view theytake up too much room in a 3 metre RHIB and add too much weight, complexity and expense.

I’ve had good experiences with Aquapro and Frank has with Quicksilver, so we make a short list including these plus Southern Pacific and Zodiac. Initially we weren’t aware ofAB and Seafarer and later add these to our list. All sellers we speakto are able to provide a complete package including outboard and are willing to negotiate deals.

Frank and I discuss design with Neil at Seafarer

Ruggedness largely relatesto selection of pontoon material and the current fourmainstream offerings are plasticised polyvinyl chloride (commonly known as pvc orvinyl), blends of pvc with thermoplastic polyurethane (TPU), blends of polychloroprene (commonly known as Neoprene) with chlorosulphonated polyethylene (commonly known as Hypalon) and lastly straight TPU.

In each case these materials are used to coat a polyester or polyamide (commonly known as nylon) fabric.Although there’s lotsof debate about the pros and cons of each material due to different product qualities and variations in design, manufacture and quality control,the above list represents anascending order of technical excellence. Manufacture and quality control are vitally important andwe’re aware of two successful New Zealand brands that encountered major problems when they switched production to China, eventually reverting to New Zealand manufacture.

Until recently the Neoprene/Hypalon blend was considered the gold standard, but opinion has largelyturnedtowards TPU taking that spot, in fact the US Navy conducted a study of pontoons in 2001 concluding “tubes constructed of TPU exhibit better key physical properties than tubes constructed of Hypalon … better tensile strength, tearing strength, puncture resistance and abrasion resistance.” It also has superior air retention, chemical (ie fuel) resistance and seams can be welded whereas Hypalon can only be glued.

Despite the above Frank and I have both experienced good results previouslywithRHIBs havingpvc pontoons and their life can be maximised by always using a storage cover and fitting chaps to provide the pontoons with extra ultra violet, abrasion and puncture resistance.

We’d been inclined towards Zodiac, their brand being synonymous with RHIBs, butthey only offered us RHIBs builtin Indonesia with GRP hulls and pvc pontoons and availability appeared to be an issue. Of the imported brands we’remost impressed by AB, produced in Belgium with an alloy hull and using a Neoprene/Hypalon blend for tubes. However wantinga few custom features addedwevisit local producer Seafarer Inflatables, based in Dairyflat north of Auckland where we’reimmediately impressed by owner Neil Curtling’senthusiasm and willingness to share his extensive knowledge based on 35 years in the industry. Seafareruse a unique hot air welding process and their productincorporatesall of the features we’re looking for and more, such as U-Deck providing a great cosmetic appearance and underfoot feel. They also produce for another well-known brand as well as repairingall types of inflatables and can produce pontoons using either a PVC/TPU blend, Hypalon or TPU. We’re also impressed by their 10 year warranty. Afterdiscussions with Neil wedecide to go a little larger than 3 metresand buy their SF340R, 3.4 metreslong with a generous beam of 1.8 metres. Although wewould have been happy with pontoons made from PVC/TPU we decide to go with the top of the line TPU, largely because this is the ultimate in durability and our RHIB is our life boatin a worst case scenario. This costs an additional $755 bringingthe price to $6,992. Neil’s attention to detail continues to impress, for example suggesting that he drill the mounting holes for wheels and rod holders in the alloy hull prior to its powder coating to minimise future corrosion.

Look for Part 2 shortly covering outboard and ancillary equipment selection and then Part 3 covering crane installation and RHIB performance.

Ourlast posting detailed how cruising at around displacement speed dramatically decreases fuel consumption and increases cruising range. It also highlighted the problems which can be encountered through cruising consistently at low rpm. Running diesel engines for long periods at idling speed is particularly detrimental and engine “wear” is said to occur at about double the ratecompared to running them under normal loading. Ideally for that reason engines should only have 3-5 minutes of idling followingstart up and then be brought up to around 1,200 rpm withsome load applied.

Not only can idling cause a build-up of carbon in the engine but also causes mirror glazing, which is the creation of a mirror-like surface finish on cylinder bores, eventually allowing more oil to pass the rings and creating more blow-by (the adverse effects of which were detailed in Part 1 of this article). Mirror glazing can also be caused by constantly running engines at the same rpm, so this should be avoided. Before shut down a diesel should also be idled for 3-5 minutes to allow the turbo to cool down. In practice this is catered for when entering your marina or approaching your anchorage.

Now let’s consider someoptions for low speed cruisingand their relative merits.

Option 1 – run both engines at low rpm

If you’re wanting to do this, avoid running below 1,200 rpm andit’s recommended to at least run at 60-75 per centof WOTfor about 30 minutes after reaching full operating temperature, then again for about15 minutes every 4 hours and then for about 30 minutes about 1 hour before shutdown. This last one is considered to be especially important to reduce soot formation and to clean the turbocharger andit’s better to spend less than optimal time at higher rpm than none at all.

Pros 

There will be a considerable reduction in fuel usage and increase in range.

All ancillary equipment driven by the engines such as power steering, refrigeration compressors, hot water manifolds will operate (unlike Option 2).

Both gearboxes and drive trains will be cooled (unlike Option 2).

Full maneuverability is maintained and there is no rudder bias (unlike Option 2).

There is no potential problem with prop shaft couplings (unlike Option 2).

In practical terms this option is easy to manage.

Cons 

Somemonitoring and planning is required for the periods at higher rpm and it is difficult to achieve on short cruises.

May cause issues with alternators.

Hours-based service costs may increase because you are using more engine hours to run a given distance.

Option 2 – run on one engine at a time at higher rpm

Underthis system only one engine is used at a time, alternatingperiodically(eg every one to two hours).

Pros 

It will take more rpm on the one selectedengine to reach your chosenspeed than it would be using two, therebyeliminatingor at least minimisingthe problem of light loading.

Fuel saving and range increase will be considerably less than Option 1, but still in the order of 10 to 15 per cent.

Higher rpm will make your in-use alternator run more efficiently.

The process is relatively east to manage.

The frequency of hours-based engine servicing is reduced thus saving service costs.

Cons 

Maneuverability is considerably reduced using one engine, particularly at low speedso this option should only be considered in open waters and not for example coming into or out of marinas.

There will be a slight steering bias in the direction away from the in-use engine ie using only the port engine the vessel will veer slightlytowardsstarboard.

The not-in-use engine’s prop will still turn or “windmill” causing drag and the gearbox to operate.The inactive engine’s gearboxmust be kept in neutral so that the engine doesn’t turn over. Most gearboxes are water-cooled using its engine’s heat exchanger, so without the engine running this cooling will be lost and gearbox damage can potentially occur. Consult your installations Owners’ Manual to ascertain for how long you can windmill. They normally suggest running your engine for about five minutes before wind milling and will advise the allowed time interval before it needs to be started again to activate the heat exchanger and circulate gearbox oil. My Caterpillar manual recommends idlingthe engine every 12 hours for five minutes, however the Twin Disc gearbox manual recommends idling the engine for a few minutes every hour, so I willfollow that guideline.

If initiating this procedure it would be a good idea to check the temperature atthe rear of the wind milling prop’s gearbox using an infra-red thermometer to see how long it takes for the temperature to rise. The lower the boat speed, the less the wind milling engine’s gearbox temperature will rise. Bear in mind there’s a good chance that some time in the future you’ll have a problem with one engine and need to run just on the other one, so this is not a wasted exercise.

Take into account that engines often run ancillary equipment, for example Rapport’s port engine runs our refrigeration compressor while her starboard engine runs our power steering and heats our hot water supply.

Some stuffing boxes have no cooling system beyond the sea water coming into it, others have oil or grease lubrication to keep temperatures down, while others and more particularly most dripless shaft seals are cooled with sea water supplied from the engine’s sea water pump, so for this latter category no cooling will be supplied if the engine is not running.

Note that some vessels have a system where either engine can supply cooling water to both shafts. However if this is not the case it is best to comparethe temperaturesof the not-in-use shaft seals with the in-use shaft seals using an infra red thermometer to determine for how long you can allow wind milling. A temperature up to about 40dC should be OK, in fact as a general rule mechanics say if the stuffing box is nottoo hot to touch it’s OK (be careful doing this though). Another measure is that stuffing box temperature should be 7-22dC above sea water temperature.

Note that some cruisers have adopted measures to eliminate wind milling. At an extreme level one cruiser crossing the Pacific decided to remove oneprop until half way across, then replacethe prop and removethe other one so the in-use engine could be changed. This was done at sea using a block and tackle to support the prop’s weight. At a less extreme level it’s not uncommon for long distance cruisers to install a mechanical or hydraulic system enabling either prop shaft to be locked so it cannot rotate. I have discounted the use of such a system based on the inconvenience and practicalityof changing over engines and the compromise to maneuverability in the event of an emergency.

When an engine is driving your vessel it is trying to push the prop shaft and coupling flangetowards the engine, therefore not putting any load on the securing bolts. When the prop shaft’s wind milling it’strying to pull away fromthe engine and therefore your coupling flange, soconnections should be checked initially and at regular intervals thereafter.

Option 3 – run both engines with one engine at higher rpm than the other

Another option isto run one engine at high rpm and the other at low rpmso that all engine-driven equipment is operating, then interchange every couple of hours or so. If adopting this option avoid running the low rpm engine below1,200 rpm for the reasons outlined in the opening comments.

Pros 

The issue of light loading is eliminated.

Economy gains similar to running two engines at low rpm are achieved and range is increased.

There is littleloss of maneuverability.

There is no issue with cooling of gearboxes and shaft seals.

There is no issue with prop shaft flange connections.

The process is easy to manage.

All engine-driven ancillary equipment will operate.

Cons 

Both engines are stillrampingup engine hours, so no servicing costs are saved.

There will be a very slight steering bias in the direction away from engine operating at higher rpm.

The alternator’s efficiency is compromised for the engine running at low rpm.

Conclusion

As mentioned early on Di and I prefer to cruise much of the time off the plane, even when cruising long distances,so considering all of the above options here’s a practical solution based on Option 2 for Rapport.

-Start both engines and leave the marina using bothat low rpm (although preferably above 1,200 rpm wherever possible)providingmaximum maneuverability.

-When in openwatersshut down the starboard engine and as temperatures rise, gradually increase rpm on port to about 1,850 = 66 per cent of WOT. This will operate refrigeration and efficient alternator operation and battery charging at higher rpm. The power steering willnot operateso hand steering will be necessary, however this is not much of an issue in open waters. Any time that power steering and autopilot is wanted I can start the starboard engine.

-When the freezer reaches its operating temperature (after roughly three hours on first day outand on subsequent daysafter about an hour), runthe starboard engine at about 1,850 rpm and shut down port

–Then continue to alternate engines as required about hourly.

For subsequent days wenormally use the genset every morning so the batteries are fully charged at that time and the alternators don’t need to run at high outputs. Every several engine hours I’ll run both engines at about 2,200-2,400rpm for 15 minutes or so as well as doing this for about half an hour an hour before shutdown.

Happy Slow Cruising

 Although fiveof the six boats we’ve owned since the 1980s have been planing boatsa large chunk of ourcruising has been in the Med aboard Envoy at around 6 knots. During that time we really grew to enjoy life in the slow lane and now find that even though our current boat, Rapport, is capable of about 20 knots we prefer to cruise mostly around 8-10 knots.

Most our time aboard Envoy we cruised at about 6kn. Max speed was about 8kn

Most cruisers we speak to own twin-engine planing vessels and many of these choose to cruise on the plane when going some distance to their destination, but then cruise off the plane in the general area around their destination. There are some goodreasons for this philosophy including some of these:

– You’re on the water torelax so why not enjoy the journey as well as the destination

– Helming at slower speed needs less attention so you can leisurely enjoy the scenery at your leisure and have more time to navigate safely, especiallyin what may be an unfamiliar area

– Many skippers prefer to tow their RHIBs at slower than planing speeds

– You’re often close to shore where in any case speed is limited to 5 knots (within 200 metres)

– At slower speeds you generally don’t have to movegear aroundas you often need to in all but calm conditions when going on the plane

– At slower speeds you’re not generating so much engine noise or causing so much wake

– Slower speeds aregenerally more comfortable for crew and it’s easier to undertake activities like making cups of coffee, using the head or having lunch under way

– At slower speeds your journey will take longer allowing more time for battery charging, for engine-driven compressors to reduceyour refrigeration temperatures and for manifold hot water heaters to heat up. This is important because if for example we leave our marina for Oneroa and cruise at planing speed after the engines are up to temperature the journey will take about 90 minutes and this is insufficient time for the refrigeration to becomefully effective. At 8 knots or so the cruise will take about three hours which allows plenty of time. This is not so much of an issue on the following days when refrigeration is already cold

– At slower speeds you can troll and catch a kahawai or kingi on the way (good luck withthat one!)

– Due to lower rpm at slower speeds you’re saving a considerable amount in fuel costs and increasing your cruising range between fueling stops

In addition to these factors by nursing your engines along at low rpm you’re looking after them right? Actually NO – this is quite wrong so read on.

Although Rapport’s top speed is about 21kn fully-loaded, we prefer to cruise at 8-10kn

So let’s focus on reduced fuel consumption and increased rangeeven though weand most people we know aren’t greatlyconcerned about fuel costs, understanding this is one of the cheapest of boating costs.

Here are fourexamples of fuel savings and increases in range (taken from Pacific PowerBoat magazine boat reviews). Note that fuel usage expressed in litres per nm is more relevantthan litres per hr as the former takes into account the shorter distance traveled due to slower speeds.

1. Nimbus 405 13.3m LOA planing vesselwith twin 200hp Volvos and shaft drives:

At 3,000 rpm = 17kn, 95.9 litres/hr, 4.4 litres/nm, 200 nm range

At 1,000 rpm = 7.3kn, 6.5 litres/hr, 0.9 litres/nm, 1,000 nm range – sofuel usage per nm decreases and range increases by a factor of about 5x

2. Absolute Vavetta 14.9m LOA semi-displacementvessel with twin Volvo Penta IPS650 “Pods”, each 480hp:

At 3,000 rpm = 18.7kn, 112 litres/h, 6 litres/nm, 272 nm range

At 1,500 rpm = 7.3kn, 21 litres/hr, 2.9 litres/nm, 564 nm range

At 1,250 rpm = 6.1kn, 9 litres/hr, 1.4 litres/nm, 1,137 nm range – so fuel usage per nm decreases and range increases by a factor of about 4.2x

3. Maritimo S55 17m planing vessel with twin Volvo D13 each 400hp and shaft drives:

At 2,100 rpm = 23.8kn, 226 litres/hr, 9.5 litres/nm, 430 nm range

At 900 rpm = 8.1kn, 26litres/hr, 3.2litres/nm, 1,280nm range – so fuel usage per nm decreases and range also increases by a factor of about 3x

4. Circa 24 –26m LOAdisplacement vessel with twin Scania DI 090, each 250hp @ 1,800rpm and shaft drives:

At 1,500 rpm = 12.3kn, 39.2 litres/hr, 3.2 litres/nm, 3,234 nm range

At 1,000 rpm = 8.7kn, 13.3 litres/hr, 1.52 litres/nm, 6,809 nm range – so fuel usage per nm decreases and range increases by a factor of about 2.1x. Note that at 6.5kn the range increases to over 10,000nm

Theseexamples include displacement, semi-displacement and planing vessels and similar results apply to all standardvessels including single engine vessels and yachts under power(however I’m not sureif this applies with foils.)

The above resultsare based on running both engines and we can see that reducing rpm results in a substantial decrease in fuel consumed per nm combined with a substantialincrease in range as a result of cruising closerto the vessel’s displacement speed where the boat’s hull becomes wonderfully efficient. That’s why long distance cruisers are nearly always displacement vessels or faster vessels cruising at displacement speed. The figures would be even more impressive if I’d compared maximum rpm with idling rpm, but I wanted to compare realistic speeds.

Howeverthere are somedownsidestocruising at low rpm and I want to mentionthese as well as suggesting several alternative options to minimise their effects. These thoughts are based on our own experiences and some internet research as well as discussions with four diesel mechanics over the last several years.

Diesel engines are not designed to be run for long periods at light loading, which is defined as rpm less than 40 per cent of wide open throttle (WOT). On the contrary the suggestedrule of thumb is to run enginesat 60-75 per cent of WOT for 60-75 per centof the time,this 60-75 per centrange beingthe range of mechanics’ varying opinions.

So what happens if you do consistently run at light loading rpm?

At low rpm and therefore lower than optimum engine temperature the piston rings don’t seat so well resulting in faster wear, additional blow-by (more than double thenormal), oil fouling of components such as turbos and carbonisation.Blow-by is the phenomenon whereby combustion chamber gasses consisting of unburned fuel and water vapour as well assoot bypass the rings causing a harmful sludge to build up on the rings in the processand to enter the crankcase. Some blow-by is normal, but increased levels cancontaminate lubricating oil forming a sludge that can partially block lubrication feed lines as well asacids that attack engine parts,often resultingnot only in later engine problems but in significantly reduced engine life.

This is one of several reasons why engines used in commercial vessels generally have a longer life span than in pleasure vessels, that is theirengines are mostly selected according to their intended operationalspeed and therefore rpm.

Another cause of increased blow-by is over filling lubrication oil so never add oil beyond the dipstick marking.

Additionally alternators don’t operatesowell at low rpm. For example aboard Rapport which has24V battery banksour approx 50amp alternators charge at 23 amps at 1,170rpm and 36 amps at 1,510rpm – a 57 per cent difference. At low engine rpm alternators’ cooling fansalso run more slowly causing alternators to overheatparticularly in the early stages of charging when the battery banks need for charging is greatest and the alternators are working their hardest. Leaving the marina this should not be too much of a problem as most vessels have shore powered chargers.

A negative for running slower is it results in more engine hours accumulating for the same distance cruised theoreticallyresulting in an increase in service costs, though practically many vessels have an annual service without reaching their hours of service threshold.

But don’t despair as there are several options available to run vessels at lower speeds without compromising engine wear or longevity, each option having its own pros and cons. 

Read about these options in our next posting.

As I write this we’ve been in Level 4lock down for nearly five weeks now and hopefully we’ll be going down to Level 3 next week and 2 the week after. So let’s hang on in there.                              

From a boating perspective we haven’t missed out on too much as until the last few days the weather has mostly been miserably wet, windyand chilly. Roll on Level 2, warmer weather and the resumption of boating – we can’t wait!

Here’s an edited version of an article to appear shortly in Pacific PowerBoat re cruising around the Ponui Island area.

In Auckland we’re spoiled for choice of great cruising destinations with about 1,200square miles of the mightyHauraki Gulf and dozens of islands on our doorstep, explainingwhy Auckland is said to have the largest number of boats per capita in the world.                                                                              

One of ourfavourite inner Gulf islands is Ponui. Maori were the island’s first inhabitants during the 1400s and evidence still remains of 23 separate pa sites. The island was purchased in 1853 by the Chamberlin family, who remained through the generations and still farm the island to this day. Ponui translatesas “long night” and judging from the number of cruisers who frequent this area we’resure there’s been many anenjoyableand long nightspent here.

Ponui is about four miles long in a north to south direction, one to two miles wide and indented with numerous bays and coves offering at least 20 good anchorages, wellspread around the island allowing cruisers tofind safe shelter in all wind conditions. The highly informativeRoyal Akarana Yacht Club Coastal Cruising Handbook (a must have on board for cruisers) provides excellentinformation on most of these anchorages, so we’ll focus on just threeof our favourite areas.

By far Ponui’s most popular anchorage is Chamberlains Bay (also called North Harbour) bordering the northern coast’s Ruthe Passage separatingPonui andRotoroa Islands. This large bay offers great shelter in westerlies through to southerlies and for light north-westerlies and south-easterlies, although in stronger south-easterlies an uncomfortablefetch comes into the bay from the Firth of Thames. You’ll notice that Coastguard have a mooring for their rescue vessels in the bay’s north-west corner.ChamberlainsBay (note spelling of this bay is different to that of the Chamberlin family name) has no particular hazards except for itsmuddy bottom gradually shoalingtowards the southern shoreline. Immediately to the east are two great sandy beaches easily reached by dinghy. If anchoring off these beacheswatch out for the rocky outcrop between the two beaches and monitor your depth. Part of Chamberlains Bay’s appeal is that if the wind shifts to the north or east boats can easily moveless than a mile across to Rotoroa’s South-West Bay to shelter. Thisbay also has three moorings available to rent by prior arrangement at $25 per night. The Salvation Army ran an alcohol addiction treatment centre here from 1911 until 2005 and during that time no landing was allowed. It’s reputed that sometimes desperate alcoholics swam out to boats moored here trying to score a drink. Nowadays visitors are encouraged, but no dogs are allowed as Rotoroa is a wildlife sanctuary with kiwi and weka abounding. It’s well worth visiting their interesting Exhibition Centre and your kids will certainly love the nearby brick jail house. You’ll have to avoid the temptation to leave them there! Takea walk over the island for spectacular views of the Firth of Thames and visit Men’s Bay and Ladies’ Bay on Rotoroa’s east coast – great anchorages in settled westerly conditions. Formerly cruisers could only gazeat these near-perfect beaches from afar, but can now enjoy their white sand, crystal clear waters and gnarly shade-providing pohutukawa trees.

Shark Bay on the island’s western side bordering the Waiheke Channel isn’t mentioned on the NZ 5324Chart for this area, but it’s the bay to the north ofOranga and Poroaki Bays. Oranga Bay is too shallow for anchoring, but take your dinghy in to see the shipwreck on the shoreline with its impressivepropeller and the nearby remains of two boilers. You’ll also see plenty of rays gliding across the seabed searching for kai. 

Shipwreck in Oranga Bay on a great early July day

Close up showing the wreck’s huge propeller

Poroaki Bay can be recognised byits several homesteadsand protruding western headland providingprotection from the prevailing south-westerly wind. Very often there’s also a large powered barge moored close to shore. Between Shark Bay and Ponui Head to the north are two unnamed bays with excellent sandy beaches and shelter from southerly through to north-easterlywinds, but be aware of an unmarked rock south west of Ponui Head (marked on chart). The only negative for this area iswakes produced by large motor vessels travelling at speed through the Waiheke Channel.

Stunning unnamed bay south of Ponui Head

Barge at Poroaki Bay

Bryants Bay on Ponui’s north-east coast is a settled weather anchorage suitable for northerly through to south-westerly winds. It’s well protected by Scully Reef and consistsof three small bays, two of which are really stunning, together with a large anchoring area outside these bays. This is an area where we’re often happy to anchor for several days and holding is good, but be aware of close to shore rocks. About half a mile south is another well sheltered bay with a finesandy beach.

Fishing is generally good around Ponui, particularly on the eastern side in the Firth of Thames and we’re always able to feed ourselves,however on the north-western side be aware of the Te Matuki Marine Reserve extending across to Awaawaroa Bay on Waiheke Island’s south coast.

There are large signs on PonuiIsland’s foreshores advising the island is private property and that no dogs, fires or camping are allowed. I spoke to one of the island’s three farm owners who advisedboaties mayland on beaches provided they observe the above limitations.Ponui is home to nearly2,000 brown kiwi, descendants of just 13 released in 1964 anddogs and ferrets are theirmain predators so there’s good reason to ban dogs. While most dog owners are responsible a minorityapparently think leashed dogs are not a problem and that rules don’t apply to them. However even leashed dogscanupset farm animals andwildlife whiletheir scent is an issue in bird breeding areas sometimes causing birds to abandon their nests.

There is no fuel, water or supplies available in this area, except for wine at the very pleasant Man O’War Vineyard. On a fine summer’s day you’ll find dozens of inflatables ashore hereenjoying the sandy beach and the selection of winery beverages and snacks. Closest groceries are at Rocky Bay while for fuel and water you’ll have to make the eleven mile trip to Pine Harbour marina.

We really enjoy anchoring in these areas around Ponui and hope you will too, but remember if going ashore to act responsibly by taking no dogs, lighting no fires and taking your rubbish away with you.

Next Post will be about cruising at low rpm without compromising your engines’ performance and longevity.

Great to see the days are finally starting to stretch out a bit and it’s now light from about 0630 until about 1815.

Although official Spring started on 1 September, true astronomical Spring occurs with the Vernal Equinox on 23 September while Daylight Saving commences a few days later on 26 September – bring it on!

Good to see NZ except Auckland going to Level 2 giving the impression the Government is committed to returning us to normality as soon as safely possible. Dare we hope that next week Auckland will go to Level 3 and a week later Level 1? Roll on the Level 2 day so we can get back out on the water and enjoy Spring! The on water boat show due to take place early October has been canceled – another casualty of the lock down which will disappoint the boating community.

As we all know there are no qualifications needed in NZ to skipper a boat used for leisure. Personally I’ve never thought this is a good thing and that skippers of boats over a certain size – say 10 metres LOA or thereabouts should require some qualification, such as a Boatmaster Certificate. Nowadays there is a noticeablyincreasing trend towards much larger power boats and it’s not unusual to see newer vessels in the 20-25 metre range. Unlike displacement vessels, planing vessels of this length put up sizable wakes, particularly at slow planing speeds and we’ve noticed some skippers seem oblivious to this and the mayhem they cause at anchorages for example in the Rakino Channel. I was in contact with Maritime NZ recently who confirmed there is no requirement for any skipper qualification regardless of the vessel’s size if used for leisure. I must admit to finding this surprising as it means that somebody with no boating experience could potentially buy and skipper a 25 metre vessel and while it’s safe to assume most would act responsibly there will always be some that don’t.

We’ve started making our post lock down cruising plans including another trip to the Kawau area, another to the Coromandel Peninsula, Mercury Islands and Mercury Bay plus a trip of several weeks duration to Northland and the Far North. Before we finalise timing we have to await a confirmed installation date for our new deck crane, hoping to have it plus our new RHIB by early-mid November. Even thinking about this gets us excited.

I also have a new writing brief for the annual Pacific PassageMaker magazine due out early next year – an article on what tools, spare parts and chandlery the well equipped coastal cruising vessel should carry. I’ve started researching this, finding it a very interesting subject and already adding a few items to my Rapport shopping list.

So we’re back in lockdown again from Weds 18 August and it appears this could last a few weeks. From the boating perspective it’s better for this to happen now than later, as we move into Spring next month. It seems it was inevitable that the delta variant would hit our shores and while it’s all too easy to criticise aspects of how NZ has handled the situation (egthe way in which rooms for quarantine are allocated) our infection numbers are remarkably low. If we had the UK’s infection and death rates, then based on the population difference we’d be having 2,665 new infections and 8 deaths daily. While there are sad stories about people having problems returning to NZ, haven’t these people largely created their own problems?

Back to the subject of Cruising and firstly engine servicing.

We’ve used TerraCat for servicing our Cat 3208 10.4L V8 diesels asthey’ve had a very knowledgeable engineerwho knew our boat well. However he recentlyleft TerraCat and after considering our options we decided to change contractors to Marine Propulsion (MP). The main reason for this is it’s highly desirable to have the same person doing your servicing as they get to know the peculiarities and history of your boat. We weren’t convinced TerraCat could offer this continuity. So far we’re impressed with MP. The engineer who’s now doing our servicing is actually one of MP’s directors (so unlikely to be leaving)and he suggested coming on board a week before the service to familiarise himself with Rapport and discuss our expectations – impressive service. We wanted somebody who will not only change oil and filters, but proactively look for potential issues and provide advice on preventative maintenance. So far we’re very satisfied with our move. For example he found that two pencil anodes in our heat exchangers have not been getting replaced because access is restricted and standard anodes can’t be used. Solution: he’s going to cut some standard anodes down so they fit and then some protection will be better than none. He made suggestions re filter changing frequency to save us cost without compromising performance as well as suggesting we use our spare filters first and replace them with new ones in order to turn the spares over. That’s the kind of engagement and service we want.

Useful tips

1. Barometers

Most of us have nice shiny brass barometers on one of our bulkheads and these should certainly be considered useful beyond ornamentation. So how should we use them?

The barometer’s indicator needle should be reset each morning in order to monitor changes.

If pressure rises or falls 1.6 to 3.5Mb over a 2 hour period it’s warning of a depression.

If pressure rises or falls 3.6 to 6.0Mb over a 2 hour period it’s warning of Force 6 winds.

If pressure rises or falls more than 6.0Mb over a 2 hour period it’s warning of Force 8 winds.

A drop in pressure of 15 or more Mb in a 24 hour period indicates a weather “bomb” is imminent.

As a matter of interest the world’s average atmospheric pressure is 1013Mb

2. Protection from sharp hose clips

Have you ever cut your hands or fingers on the sharp ends of stainless steel hose clamps? I sure have and to avoid this have fitted Clamp-Aid hose clamp safety guards. These are flexible silicone sleeves that easily fit over the ends of hose clamps to provide protection. Cost is about $32 for a pack of 20.

3. Mounting fittings on gelcoat surfaces

At some point we all need to add fittings such as an aerial mount to a gelcoated surface. What most of us do is drill a hole in the gelcoat, put some silicone in the hole and onto the screw and Bob’s your uncle right? Wrong. Silicone has a limited life of around 5 years, so at best water will eventually find its way in to the cavity and migrate into the substrate beneath the gelcoat. The correct way to do this is to drill a hole much larger, in  both diameter and depth than what is required for the screw, fill the hole with epoxy and then drill the screw hole in the epoxy. This will ensure that moisture doesn’t get into the substrate beneath the gelcoat. In any case silicone sealants are not suited to marine applications and we should use marine sealants like Sicaflex 291, 3M4000 or Bostik Simson MSR Construction Adhesive.

4. Paint aerosols

You normally have some paint left in the aerosol after completing your job. In order to re-use the aerosol hold it upside down and press the nozzle until all residual clears out of the nozzle. Then store aerosol upright.

We weren’t planning to do much cruising during August, but hope the lockdown is over so we can start serious cruising again from mid-Sept.