syohana
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Posts posted by syohana
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Unfortunately everything which really works has been made illegal. Some antifouling still works for some types of fouling but nothing works for all types any more. It might keep the barnacles off but the mussels and the slime are another matter...
A quick light scrub every few weeks in summer and every few months in winter, take the fouling off before it gets bad is the most effective solution. Being based at Northcote point you can nip round into little shoal bay and dry out on the tide there to clean the bottom. Nobody seems to mind there as it's full of drying moorings anyway (it has been 6 years since I was there, things may have changed). Very firm, level mud bottom with no obstructions.
boatpaint.co.nz sell quality Hempel paint, it's as good as anything else and their pricing is MUCH less than what you pay in a chandlery. They are based up in whangaparoa.
I used to get very good results with Hempel Olympic antifoul. Not sure it's working so well this year, maybe they had to take another of the ingredients out...
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Arbo 1096 from Arbosil is the absolute business. One component, sticks very strongly to acrylic (and is designed and tested for that purpose, not just for glass). Easy to work with, relatively easy to clean, not too thick so it's easy to squeeze out. Pretty much everyone uses it as the main product for boat windows in the UK. I've been trying hard to find it in NZ but I can't. If anyone tracks it down here then please let me know. It's not only a really good product but cheap too! Only about $13 for a big cartridge of it.
If you need a decent quantity it might be worth ordering it from the UK via NZPost Youshop. You can get it at good prices, single tubes or cartons from Dortechdirect.co.uk
You do get through a lot of it - it's important to use a really thick bead to provide flexibility in the joints and not tighten down the window to squeeze it out. Buy twice as much as you think you need. If anyone is ordering some in then I'd be interested to add a few tubes to the order, maybe club together and get a carton.
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Wheels:
There's nothing wrong with gel batteries when using a special gel charger. The OP is using an AGM charger so it's rather academic to discuss the advantages of gel. My analysis was based on the OPs specific requirements rather than a more general comparison of AGM and gel.
AGM batteries are the correct solution for the OP and if he's not sure what brand to get then picking the heaviest available at the right physical size is a good rule of thumb to ensure he doesn't buy rubbish.
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Gel batteries have much lower charge voltage than AGM. The problem is the batteries you had in it were Gel type not AGM. Gel batteries REQUIRE a special Gel charger which operates at significantly lower voltage than an AGM charger. If you charge a gel battery at AGM or flooded lead acid voltages then bubbles will very quickly form in the gel from overcharging. The bubbles separate the gel from the plates and the battery becomes useless.
AGM batteries are much more tolerant and can be charged by a normal lead acid battery charger but they will last longer if you use a charger with special AGM settings. Most AGM batteries have similar charge voltage settings, there can be small variations but essentially any AGM battery will probably be OK in this unit with the existing charger.
AGM batteries have fibreglass mats between the plates which hold the gel against the plates and make it more resistant to bubbling away. You still don't want to over charge an AGM because even with glass mats it will cause a bit of the gel to bubble away. AGM and Gel batteries cannot be topped up so once the acid has boiled off they are dead.
Conventional flooded lead acid cells can be topped up with deionised water, which means it doesn't matter if you charge them at slightly higher voltage as long as you remember to top them up regularly. They can really bubble away and let off gas when charging so need to be vented.
For this kind of traction application flooded lead acid is still the best (Trojan is a good brand). Trojan also do AGM batteries. I guess this unit is not always vertical so there's a risk of flooded batteries spilling. AGM would be chosen for zero maintenance and no risk of acid spilling.
So, the answer is get a set of AGM batteries of the same spec as the originals. There's no need to get bigger ones, your batteries only failed because they were gel and not AGM.
When selecting any kind of lead acid batteries for a heavy duty deep cycling application like this then the heaviest duty ones are literally the heaviest - thicker lead plates are more resistant to buckling and will last longer but they weigh more and cost more. If you compare the KG weight of two batteries of the same spec and one brand is heavier, you can be pretty sure that's the better brand.
Trojan produce different types of battery for different applications. Their "motive" range are the really heavy ones for traction purposes. An "H" on the end of the model number is for extra heavy plates which allow you to discharge it deeper more often.
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looks like maybe a chinese copy of an andersen, or a very old andersen? Best get a machine shop to make a cap in a lathe, tight fit, press it on when hot and it'll stay on forever. Custom mechanical engineering jobs like that are not as expensive as you might expect, probably cheaper than the spare part in the unlikely event it is available.
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Hydrogen is not happening any time soon. If you want unlimited range then solar panels are a cheap, easy, silent solution. Most boats can carry enough solar to do at least 3 knots in direct sunlight without taking anything from the batteries. Motorboats without shade from rigging and multihulls with more space can go as high as 5 knots in full sunshine or up to 3 knots on a bright cloudy day.
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1 hour ago, bigal.nz said:
Yeah that's awesome - found that in the app now too. Thank you,
2.8 Knots seems to be the highest current value I could see predicted in the next few days.That's probably only the tide not the ocean current. You'd need to add the two together to find the total as ocean currents might be significant around Reinga (and amplified by the shallow water, which the forecast model might not include).
There are ocean current forecasts available from saildocs.com which you can download as grib files and view using the grib plugin on OpenCPN. You have to really dig into the documentation for saildocs to find how to request the currents forecast but they are very useful for ocean passages. Just be aware that the forecasts are for quite large grid squares so they will give you the general situation that there's a strong east-west current around the cape (for example only, I didn't check) but not the detail of what that does when squeezed into a small shallow area of a few kilometers from land.
If in doubt, go right out! (But if you don't have a go, you'll never know
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20 hours ago, wheels said:
Well you could also consider, when did your engine last break down. It may seem like lots of engines break down. But with the number of engines out there, they are actually very reliable. Where as full electric has the complexity of Batteries, and Li being full of electronics, Chargers and other boxes full of electronics full of the magic smoke. Then the electric motors. Quite a complex system and I learned a very important lesson from you BP. Keep things simple. I used to be far too techy on my boat. I also seemed to be always replacing something. Some Pump, or some electronic thingy. And I thought you know? BP has a point. My next boat (if I ever get one) is going to remain simple.
Back to engines, the biggest problem the Airo industry has is not just the battery. Although they are getting very close to sorting that by the way. But the main issue is getting people to change their thinking to Electric propulsion actually being safe. It is probably safer, but that is not the perception.You're right that keeping it simple is the key. Don't confuse the unknown with complexity though.
An electric propulsion system has only one moving part (plus the balls in the bearings if you're pedantic). A diesel has hundreds of moving parts. The starter motor alone has more moving parts than a whole electric propulsion system!
Not only that but a diesel vibrates everything else in the boat, potentially causing all sorts of other things to work loose or fail before their time, from hull fastenings around the engine mounts to electrical wiring, even metal fatigue in the rigging. Not to mention all those water hoses, exhaust, electrical cables and seacocks all vibrating against each other and chafing, competing to start a fire or sink the boat.
IMHO if you're really keeping it simple then electric is the way to go. Of course electric can be complicated if done wrong but still not half as complex as the simplest diesel.
If you're keeping electric simple then a pod motor is usually the way to go.
If you're keeping hybrid simple then a parallel hybrid, belt driven by (and driving) the propshaft of a conventional diesel is the way to go NOT usually a separate genset - serial hybrids are complicated. There are some situations where serial hybrid is the best option but it's rare.
You may be concerned about getting your electrics wet but the pod motor is of course waterproof and submersible, as are most of the water cooled inboard motors. Waterproof chargers are readily available too.
But a waterproof charger isn't really necessary once you eliminate all those hoses, seacocks and even the hole in the hull for the propshaft. You may never have any bilge water ever again!
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7 hours ago, CarpeDiem said:
So given the Torqeedo's relatively short warranty period, and the no commercial use restriction, I am guessing we're a way off seeing motors that will last decades of daily use?
It doesn't give me any faith in the technology when the manufacturer sets the warranty period at 12 months.
Do you think we're likely to see 10 year motor warranties (subject to any servicing requirements) in the near future? (I realise batteries will always have short warranty periods). But if the motors are designed to last decades of daily use then the warranty needs to reflect that.
Torqeedo is a quality product which is widely used on commercial vessels in daily use, including our own safety boat. The warranty is two years, not one year.
Our main product line for yachts, launches and commercial vessels is Combi. If you want an outboard to last a lifetime and pass to your grandkids then choose Combi. Torqeedo's big boat range is more aimed at performance (lightweight, high speed, high price). For a planing boat, superyacht tender, a very small dinghy or a racing yacht I'd usually recommend Torqeedo.
Combi started supplying electric outboards 41 years ago. The outboards they supplied 41 years ago are still in daily use on hire boats. Since then the designs have been refined and optimised continually, with innovations such as AC motors and IPM motors. They are 100% reliable. the warranty is nominally two years but as far as I know there has never been a failure of a Combi motor so the question of warranty is irrelevant.
The motors go up to about 4000 hours between services (at least two years of daily use, on hire all day). A service is just a change of bearings and seals. For comparison, a typical two stroke is scrapped after 2000 hours, by which time it has been serviced 20 times.
Combi still provide service and support for those 41 year old motors and the many thousands they have produced since. Some fleets service their own motors, which is not difficult. Others return the whole fleet of motors to Combi for servicing.
In leisure use, you'll never reach the first service interval, although the seals might eventually perish so maybe good to replace them after ten years.
On our safety boat we have a Torqeedo which is in daily use. We chose it because the big prop is better for towing. Our hire boats have Ruban Bleu ECO pods. They are similar to the Combi product but use a brushed motor so they require a 1000 hour service to change the brushes. We selected them over Combi mainly because they were in stock. Combi had a long waiting list for production after lockdown and we couldn't get the Combi here in time for the summer season.
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We're talking about a dinghy right? I am not aware of any dinghy electric outboard share services? Although that would be cool...
I was talking about a tender so I assumed that it would come in the package with a shared yacht. Smaller yachts can use the same outboard on the dinghy and the yacht. It might be a nice idea for clubs with big mooring fields like PYBC or Weiti to have a pool of outboards for their members.
5 hours ago, CarpeDiem said:I am not aware of any countries that have completely banned 2 stroke use? Interested to hear which have?
I know that Sweden tried to do it a year ago, but there was an uproar at the cost to replace 1million perfectly functional outboards and I am pretty sure it never went ahead?
Many countries have banned the sale of brand new 2 stroke outboards. In fact l will get pedantic here, they have banned the sale of outboards that don't meet specific emission standards.
NZ is definitely behind on the new sales ban. I expect us to follow Australia when we finally do it.
Two stroke sales were banned nearly 15 years ago in Europe. They don't need to ban using them because there are hardly any of them left to use. Nearly all the remaining petrol motors are four stroke and the EU should soon be legislating to phase out four stroke as well.
They are banned from use in large areas of Europe on a regional basis not national. Netherlands, Germany, Austria, Switzerland all have large areas where either two stroke only (eg. on the Bodensee) or more often ALL internal combustion engines are banned and have been for a long time. That's why all the major electric boat motor manufacturers are based in those countries, the market there is huge. There are hundreds of thousands of electric boats there already, NZ is very late to the party.
NZ has left it too late to eliminate two stroke by banning sales. In order to meet international treaty obligations on emissions targets the only option for NZ will be a ban on using them, it's too late now for a sales ban to work because there are just too many in circulation. I expect this will be incremental with local and then regional bans first, I would expect them to be banned on lakes and rivers very soon.
Lots of regional bans on use in North America too. Lots of electric motors selling over there to guys like these:
QuoteWe have a different idea of "budget"
A friend of mine has one of these he is extremely happy with it. At $420 he's gotten his monies worth and then some. He keeps expecting it to pack up. Admittedly it wouldn't be my choice for a long term overseas cruise, would definitely want something like your more expensive products with a proper track record and international support.
That's a trolling motor not a real outboard, it's designed for a very different purpose. You might get away with it if your mooring is in a very sheltered location, close to the landing.
There's nothing sustainable about buying a disposable toy motor and replacing it frequently. The carbon emissions from manufacturing replacement motors would exceed the savings from running it. To be truly sustainable, a motor needs to be designed to last decades of daily use. The price tag may look steep but the lifetime cost is far lower than any other option, not just to your wallet but also to the environment.
Torqeedo has just launched a new lower priced option called the Travel 603, it's a smaller version of the 1103 best suited to small dinghies and short trips. The price tag will be a lot more affordable but it's a real propulsion outboard not a trolling motor. We don't know the NZ RRP yet but I expect the first batch will probably be sold out long before they even arrive, mainly for yacht tenders.
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44 minutes ago, waikiore said:
SYO some props are controllable pitch -or like mine have two different pitch settings, not the Autoprop which sets itself -not ideal in a big and bouncy sea, check out Torqeedo pricing in the UK for an indication in a competitive market where it really lies against other small (four stroke) outboards.
True controllable pitch props are popular on Norwegian workboats and big ships, not seen many outside Scandinavia. Nice things though. It's a completely different way of driving a boat, controlling your speed and often even fwd/reverse with the prop pitch while leaving the engine running at a steady speed. Too big, too expensive and too complicated for most yachts.
Our Torqeedo pricing is the best in NZ and we can give a little bit more off if you pay by bank transfer but our margins are pretty tight. Unfortunately Torqeedo pricing in NZ is high due to a long, complicated supply chain, we are a dealer at the end of the chain and can't source direct from Germany.
We are the distributor for our other brands, not just a dealer. Those are imported directly from the manufacturer so we can give you the same prices you'd get in Europe (plus the shipping cost). Combi motors are 100% made in the Netherlands (except genuine Curtis motor controllers which they import. Motors are sometimes built to order so there can be a waiting time.
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6 hours ago, CarpeDiem said:
A second battery retails for around $1600. The 1103c batteries are ~35ah Lithium Manganese, so at $1600 it's expensive for what it is.
So the motor is expensive no matter how you look at it. And adding that too a non electric ready cruising boat you have the added expense of charging, presumably overnight so your dinghy is ready for use the following day.
My Yamaha 3hp 2-stroke cost $1150 in 2016. Since then it's had exactly zero $ spent on servicing and maybe $200 on fuel, oil and carbon credits if that.
I can't find any numbers on the break even usage when compared to petrol. It simply doesn't stack up for me. I wish it did, I would love to make electric work for me financially or even be closer than it currently is. But $3000 is still a lot of money.
Either the price has to come down or regulation and fuel levies need to come into effect to drive adoption.
All that said there are some cheaper options out there than the Torqeedo. Especially so in the DIY space. I have worked out that I could get into a 85lbs thrust motor with a 40ah lithium battery pack for around $2000. If this petrol outboard of mine ever packs it in...
If it is in daily use then an electric motor can break even in a year and then you're saving money compared to a petrol or diesel.
If you're not using your boat regularly then it will take longer. It's not very sustainable to have boats sitting around not being used, better to join a boat share, hire or charter, that way the electric motor will be fully utilised and can pay for itself in a year on the fuel and maintenance savings.
Diesel and petrol need to be phased out in the next ten years so you can expect some serious fuel tax increases and hopefully we'll get free electric charging points like we are seeing for cars, some stick and some carrot.
Two stroke outboards are already banned in almost every developed country, it's a mystery why they are still allowed in NZ but it can't continue for long. It's madness to buy a new two stroke when it could be scrap metal next year. One two stroke outboard produces more emissions than 100 modern cars with catalytic converters and such!
It'll be a bit longer before four strokes are banned but if you don't use it that often then you'll probably have to scrap it when still has very few hours on it.
Don't get obsessed with Torqeedo, they are great motors especially if weight is your main concern but also look at the Combi H-Thruster and E-thruster, commercial grade products, all metal, user serviceable, bulletproof and highly refined.
For a budget priced option there's also the Ruban Bleu ECO pod. We don't have this in a clamp-on version yet, it's mainly designed to replace a rudder but it can be adapted on an outboard bracket, as we have done on our mini catamarans. This is the same kind of solid alloy and stainless build quality as the Combi but it utilises a brushed motor to keep the price down. It's maintenance free for 1000 hours so most leisure users will never need to change the brushes.
Avoid the cheap rubbish and DIY - it seems simple to stick a motor on top of a two stroke leg but there are reasons none of the major, proven outboard designs do anything like that. Sooner or later water will get into an air cooled outboard motor and kill it. If you go with water cooling then you need an impeller and you need to flush it, all that stuff you hated about you petrol outboard and it gets complicated. Plus you lose a lot of efficiency in the gears compared to direct drive. Worst of all, it will make a horrible whine. Underwater motors are silent (except the older Torqeedo designs which have planetary gears - direct drive is silent).
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23 hours ago, Black Panther said:
Yes. Coincidentally there's is a sistership to a previous boat of ours.
They have a website at sailingcinderella.com if anyone is interested in their story. I have invited them to visit the forum here and give their perspective.
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25 minutes ago, Black Panther said:
Coincidentally we had dinner last night with a couple that sailed here from Seattle, 35fter, all electric. Happy as and would never go back.
Ava and Pajo? They are real sailors who use their sails. They get by with a tiny battery capacity and minimal charging capability. Respect to them for doing it right. It's about having the right attitude, remembering you're on a sailing yacht and not a motorboat with a mast.
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1 hour ago, waikiore said:
I have probably spec;d more yacht props than anyone else in NZ over the past ten years and always calculate to use the full torque and horsepower of the diesel / gearbox combo.
With a fixed prop you can only use the full torque at one chosen RPM.
If you set the prop to use the full torque at maximum horsepower (say 3200 rpm) then it won't be using anything like the full available torque at any other RPM. therefore if you read off the torque curve that your engine can produce 20hp at 2200 RPM, that's not actually true because you didn't set the prop to fully load the engine at 2200 RPM, you set it to be fully loaded at 3200 RPM.
Selecting a prop for maximum peak horsepower output results in the engine revving much higher than necessary at cruising speed, basically unloaded. Since you spend most of the time at cruising speed your system will be inefficient most of the time.
CarpeDiem could probably reach the same cruising speed at much lower revs with a prop optimised for the cruising speed, but then they might be over-propped at WOT and unable to get up to the max revs of the engine. If you only run at cruising speeds, being a bit over-propped can be good. CarpeDiem thought they were using most of their horsepower at cruising speed because the revs were relatively high, but the revs are high because the prop is not optimised for that speed and it's running unloaded.
Brunton's Autoprop is a clever solution to this catch-22 because it changes the pitch all the time according to the torque. It's for keeping revs low when motor-sailing too. I'd be interested to experiment with an Autoprop with electric propulsion where there's huge torque available at the low end, it might need a redesign for the electric torque curve though.
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1 hour ago, Martin Wright said:
Awesome, Syohana! You and Wild Violet are thinking along the same lines. I will put the to Moon Engines. Do you know of a workshop that can make this sort of stuff?
If you had a workshop do the work for you as a one off then you may need to win the lottery first on the labour time alone, but it might be possible to make the frame yourself if you have plenty of spare time. Lightning Bolt in Auckland are very good for making up custom shafts and flanges, they might even do the whole job.
The simplest approach for a one-off is using U section alloy or steel frame bolted together like the Electric Yacht system we are currently selling on our website. the photos here should give you the idea:
https://electricboat.co.nz/index.php/product/electric-yacht-5kw-10hp-equivalent-shaft-drive-motor/
PS why not just buy this system and dump the whole diesel? This motor is so compact it will fit without a V drive.
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7 minutes ago, harrytom said:
I talking about belt driven freezer off motor.I should of been clearer.
I don't see why a belt driven freezer would use much more power than an electric one. You could perhaps put a pulley on the propshaft but I've never seen it done. Remember there's no gearbox so there's no neutral, you can't run the motor without turning the prop. How would you run the fridge at anchor? Better to just use an electric freezer.
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8 minutes ago, harrytom said:
It all sounds good as far as propulsion goes.So what happens when you turn on the freezer?Drop in power/speed
A freezer uses about 50-60 watts, negligible compared to propulsion. You won't notice any difference.
Some people use a separate 12v house battery and a 48-12v charger (necessary if you have a 12v windlass), others just have a 48-12v converter for smaller loads. A 48v windlass makes a lot of sense but they are hard to find. That will change.
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20 minutes ago, Sabre said:
There are some really big positives to going electric and making the switch is very, very tempting! Quiet and simple to maintain being the most obvious pro's but as soon as a generator/genset is added then aren't those benifits lost and in fact increase the complexity?
Day sailing from a plug in marina seems viable but I just don't see it working well on a typical cruising yacht (yet).
Fair comment. Don't forget the incredible level of low speed control and torque.
You either need shore power or a good amount of solar. Solar limits you to doing consecutive long trips only on sunny days or with time to charge in between. Most cruisers only sail in fair weather and it's usually sunny when there's no wind, so that can be OK.
A cheap, lightweight portable genset can sit in a locker for peace of mind and get pulled out once a year if you need it in a pinch.
Of course it's better if people plan their trips properly and make small changes to their behaviour so they never need a generator and enjoy their sailing more, but sometimes it's needed as a cure for "range anxiety", even if it is never used it makes people feel better about taking the leap to electric, then they adapt and realise they didn't need one after all.
If you need to run your engine more than a few hours it's usually due to bad planning (taking on a longer trip than you have time for, or going in the wrong direction for the weather)
A $400 generator is a better option than $10,000 of extra battery capacity which you only use once a year. You can get rid of the generator next time you upgrade the batteries when battery prices are lower.
Full electric propulsion might not be right yet for yachts kept on swing moorings but they do all need an outboard for the dinghy. a light weight electric one is absolutely perfect for the short trip out to your mooring. Throw it in the car with no worries about smells, oil stains, cancer or explosions! There's no cooling water circuit to flush out and no impeller to break either. The motor is in the bulb at the bottom so it is naturally cooled by the sea water passing over it. Everyone hates their unreliable, high maintenance outboard. NZ is just about the only country in the developed world where two stroke outboards are not already banned.
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This horsepower inflation thing has been going on for a while. One horsepower used to be considered adequate for a 40 tonne coal barge....*
* Propeller sizing was not a problem back then and the transmission was nearly 100% efficient. The emissions were still undesirable.
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21 minutes ago, KM... said:
My 930 was running a 9.9 Yammy Hi Thrust and it would push her into a near cyclone with minimal lose of speed. Nothing with an inboard could touch us.
I have no problem at all believing the 10hp comment
Yep, and outboard horsepower is even more overstated by the manufacturers than inboard horsepower! "Hi thrust" is the key here, you had the right propeller to get all of the available power into the water.
Diesel props are often undersized due to constraints of hull clearance or so that the engine isn't overloaded with a big alternator and fridge compressor hanging off it. Or they are sized for a maximum speed rather than a maximum thrust. They could be "one size fits all" so the standard prop on a 30hp diesel might be sized for the hull speed of the longest boat you'd reasonably fit that motor into.
Or, if they sized the prop specifically for your boat then perhaps they specified it so that the maximum rpm would correspond to the maximum hull speed, knowing that you'd never need all your horses at any RPM. Theoretically, having that reserve torque means you could potentially tow a second boat while maintaining exactly the same RPM and boat speed, the only difference would be your fuel consumption. Such behaviour might require a bigger prop.
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15 minutes ago, CarpeDiem said:
She has had a Volvo 30hp engine since new. First one was a 30hp Volvo 2003. We replaced it with the 29hp D1-30.
The propellor is also Volvo and we took that off the old saildrive system but Volvo signed off on it being the correct size for the boat/engine.
Wow, only 10hp? That surprises me.
Thanks - food for thought.
Sorry I misread 10m LWL as 10m LOA hence my discussion of 28ft waterline. 10hp may be a bit low. I overstated your cruising speed being too high, you're probably not pushing hull speed hard at 6 knots but 5.5 is still much more economical.
As a rule of thumb we recommend 1kw per tonne of displacement to get the boat up to hull speed in calm conditions. Most of my analysis was based on the displacement rather than the length so the suggested 5kw electric power remains valid but a 10kw or 15kw would not be a bad idea to give you extra power in reserve for bad weather. There's not a huge difference in cost between 5kw and 10kw motors.
Your prop is sized so as to never overload the engine at any RPM (as evidenced by your ability to take the motor to the maximum RPM). If it is sized correctly to not overload the motor at 3200 RPM then it cannot deliver the maximum rated horsepower at a mid range RPM. I still reckon you're not putting much over 10hp into the water at 2200rpm because 10hp should be enough to get a 5 tonne boat up to hull speed. After that more horsepower just makes more waves.
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1 hour ago, CarpeDiem said:
We were told to over spec the generator so it was never running at full output? It was described as a range extender and battery charger. I could see it only being used a few times a year. However, if we had gone down that path we'd also have removed the Lpg and gone full electric cooking and water heating so it would of been a bit more than just a range extender on long cruises.
Bad advice IMHO. Diesels like running at about 80% of their full capacity, a 20kw genset would be specced so that the diesel in it is running at about 80% when producing the full 20kw electric output. If you don't run it at full output (and you never would even with propulsion, cooking and an electric heater all at once) then the exhaust gets all clogged up with soot.
Quote20kw genny was matched to a 15kw motor.
15kw is overkill for this size boat. 5kw is adequate to reach full hull speed in calm conditions. The rest is extra power to push into strong wind and waves. Nice to have in reserve but not often used.
If you need a genset at all then the genset should be 5kw for unlimited range at hull speed or 3kw as a range extender or to get you home with unlimited range at reduced speed. If you need extra power to bash into a strong wind then you can draw down the batteries.
QuoteLwl is 10m. Weight is 5200kg. We cruise at 6.2knots which is 2200rpm. If we take the engine to ~2800rpm we hit Hull speed at ~7.1knots. At that point we have 300rpm in reserve, the engine maxes out at 3100rpm iirc but we don't go there.
From the system you were specified I thought you might have a 40 footer. Your diesel is about 20hp at 2200 RPM if it was producing maximum torque but I suspect that your propeller is not big enough for it to produce maximum torque at that RPM. Your 29hp diesel may never actually put more than 10hp into the water. Quite likely the propeller was specified for the original ~10hp motor the boat had when it was new so the prop isn't capable of delivering much more than 10hp considering that your new motor runs at the same RPM as the old one.
6.2 knots is not an economical cruising speed, it's close to a maximum speed. Depending on your waterline length that's probably pushing hull speed (28ft waterline=7 knot hull speed) and wasting a lot of power making waves. At 5.5kn you'd use half as much fuel/electricity.
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1 hour ago, Black Panther said:
Thank you syo.
I looked at it about 5 yrs ago and it sounds like things have improved since .
If you have the time and inclination what would you suggest to replace 90hp diesel? 100mile range@4kn 25mile @5.5. Then the biggie, not ever likely to be on a marina so how long to recharge?
As I said to CarpeDiem, it's more about specifying the right motor for your boat than replacing a 90hp diesel which might not be right and you're probably never running it flat out.
Please tell me more about the boat and the drivetrain. For 100nm range and no marina berth you probably want some sort of hybrid and plenty of solar. You can do it all electric but it will be very spendy on batteries for that range.
Anyone here have a Boat Repainted in Fiji, how did that go for you?
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We had our yacht repainted at Vuda point, total cowboys, made an almighty mess which all had to be stripped off before starting again somewhere else. It was two months of horrible work with a sander to get it all off. These were supposedly Vuda point's "recommended contractors" so I made the mistake of trusting them to get on with it while I was away for a few days. Ended up with paint on decks, fittings, windows and even some of the places that were supposed to be painted (but just one very thick coat without any of the necessary sanding or primers first!). The job was contracted to be sprayed but most of it was slapped on with big brush marks in it.
Marina manager wasn't much help, he said that company would be banned from working at the marina again but also said they'd probably come back under another name. At the time they were called "Peter's works". I had read really good reviews of a boat painter called Peter at Vuda but apparently my big mistake was that there are two guys called Peter and I had chosen the wrong one .... Since he was a recommended contractor of the marina and I got his card from them, I thought I was safe.
In Fiji there's no chance of getting a refund or getting anything put right of course. At least I had only paid half up front.
The moral of the story is don't risk it, paint can go so badly wrong in so many ways that you need to go to a professional in NZ, I learnt that the hard way.