Electric inboard engine, equivelant diesel inboard.

[lustyd]

infinite range is largely a myth for old/conventional monohulls).

Only if you require that infinite range all in one go. My point was that once diesel is gone, it's gone but until the sun goes out solar will eventually (couple of days drifting) replenish the range of an electric yacht which would mostly be sailing anyway. a "full tank" on an electric is sufficient to get out of the doldrums these days, at which point sailing regen and solar will quickly top you back up.
Traditional yachts don't use diesel for cooking so it's ridiculous to require an electric yacht to use electric just to prove it's somehow not ready for prime time

 

[BurnitBlue]

Thanks for bringing me back down to planet earth. Much appreciate the concise replies.

i have aquired a Prout Elite 37 foot catamaran. 99% was well above expectations until I opened the engine bay where I was so horrified, i was in heart attack country. An old 3hm35f was sitting there. Oily, dirty, with obvious signs of neglect and the common disadvantage of very poor access. The root cause of most marine installations. Smaller engine equals more space, better access and better maintenance. So my thoughts drifted to electric power.

No more. Back to diesel. Even at 6,303 hours the engine may run like a sewing machine. In a few days i will know. I doubt it because the boat has been unused fo over five years in a Greek dusty atmosphere. I am prepared to install a new engine if I cannot get this thing running.

 

[Supertramp]

Good luck with your engine. High hours may mean it was properly looked after, although it's the last couple of hundred that will count most.

Reading in these threads about people installing extensive solar and battery banks makes me agree that there will be a shift to electric propulsion over the next decades. What is needed is a really simple, reliable diesel generator to allow continuous motoring. Most boat diesels are based on these and they seem a much better bet than some generator sets. Not flat out running but economical cruising. Short term high power uses the batteries as well, and a limited battery only range for up to 30-50 miles. Those are limitations I could live with.

I know you can buy such systems now at high cost but it's only a short stretch from the components most of us are already installing.

 

[Tranona]

It failed because his method was flawed, not because it doesn't work. You won't get far by whipping a car, you need to change your approach to adopt new technology.

Not even close to the range of even modest electric yacht installations in 2023.


Anyway, my point remains, if you're mid-pacific in the doldrums and run out of diesel you're permanently out of diesel. Not so with Solar/electric

Give examples that have the range at comparable cruising speeds to diesel engined boats. Sure you can have greater range but at lower speeds. When making comparisons all conditions should be equal.

 

[Tranona]

Thanks for bringing me back down to planet earth. Much appreciate the concise replies.

i have aquired a Prout Elite 37 foot catamaran. 99% was well above expectations until I opened the engine bay where I was so horrified, i was in heart attack country. An old 3hm35f was sitting there. Oily, dirty, with obvious signs of neglect and the common disadvantage of very poor access. The root cause of most marine installations. Smaller engine equals more space, better access and better maintenance. So my thoughts drifted to electric power.

No more. Back to diesel. Even at 6,303 hours the engine may run like a sewing machine. In a few days i will know. I doubt it because the boat has been unused fo over five years in a Greek dusty atmosphere. I am prepared to install a new engine if I cannot get this thing running.

That engine was very popular for cats of that size. Is it driving through a Sonic? I ask because I sold the engine I took out of my latest project to go into a Catfisher which was originally fitted with that model Yanmar. The previous owner had started one of those daft "chuck it all away and start from the beginning" refits and had disposed of a perfectly good engine. Inevitably it became one of those golden opportunity ebay specials. Anyway the new owner was trying to finish it on a budget. My engine was a Perkins 103 - same as the Volvo 2040 but governed to 2800 and 35hp with a PRM gearbox. Same sort of power as the Yanmar and dimensionally virtually the same. I have heard nothing from him in nearly a year so I assume it all worked.

So if you do want a replacement a Volvo 2040, or even the smaller 2030 30hp would be worth looking at.

 

[Tranona]

Yes offshore cats are an ideal use case. Lots around like this now
Partially correct I think. It was the domestic power demands that scuppered Jimmy Cornell’s attempt.
His fast cat could easily do the 8kts plus needed to get effective regeneration under sail (which most smaller monohulls cannot, hence the infinite range is largely a myth for old/conventional monohulls).
But the twin freezers and all electric cooking was too demanding - and even, he noted, a crew who had dietary preferences that meant two different meals needed to be cooked each day.
I strongly suspect if he had a gas cooker on board his voyage could have continued (but then eventually was cancelled for reasons entirely unrelated to electric demands or the boat).

There is still the issue of energy storage capacity. Effectively you have to burn off excess generation while not motoring but still left with limited range if you want to motor and use the domestic systems at the same time.

Going the other way as many people are it is now feasible to have an all electric domestic system and keep the diesel solely for propulsion, although you can also harvest waste energy from the diesel when it is running as Nigel Calder advocates.

 

[BurnitBlue]

That engine was very popular for cats of that size. Is it driving through a Sonic? I ask because I sold the engine I took out of my latest project to go into a Catfisher which was originally fitted with that model Yanmar. The previous owner had started one of those daft "chuck it all away and start from the beginning" refits and had disposed of a perfectly good engine. Inevitably it became one of those golden opportunity ebay specials. Anyway the new owner was trying to finish it on a budget. My engine was a Perkins 103 - same as the Volvo 2040 but governed to 2800 and 35hp with a PRM gearbox. Same sort of power as the Yanmar and dimensionally virtually the same. I have heard nothing from him in nearly a year so I assume it all worked.

So if you do want a replacement a Volvo 2040, or even the smaller 2030 30hp would be worth looking at.

Yes a sonic which was installed about 5 or 6 years ago when the original sonic was showing signs of wear. I am happy to learn that the 3hm35 was considered a good engine. And yes to Supertramp 6,303 hours running time means good maintenance. So I am hopefull with such positive replies. I may even make the effort to drop my usual doom and gloom negative posts and be more positive. Makes for a happy thread. I will give it a go anyway.

Getting RCD approval may be easier with a change to electric motor with no emmisions. )

 

[penfold]

Not true. Various suppliers now offer these - notably Oceanvolt saildrive systems in the 10-15kW (15-20hp) range suitable for a 35-40 foot yacht. A number of builders now offer these as options on new build, and people like Sailing Uma have retrofitted (with supplier financial assistance, I suspect, in their case).

But cost and range remain the big issues. Most of the new build ones I have seen are serial hybrids, with 48V DC generators to give huge range (but even more cost)

None of which are OTS; they look nice, but are not even approaching the commodification of small diesels. Let's have this discussion again in 10 years.

 

[Minerva]

I think electric propulsion will be the defacto standard before too long. Speaking as a normal working family bloke, most of my sailing is weekends with a fortnight/three week cruise per year.

Most weekend cruising is decided dependant on wind & tide, so of a standard weekend electric is totally doable. During the week it’s on it’s swinging mooring the PV panels will have the batteries recharged in time for Friday. That’s got a fairly strong appeal.

During the longer cruise, we obviously go further afield which brings into call the return home to a fixed deadline (like today motoring up the sound of Jura from Gigha to Luing) For those rare occasions a small diesel/petrol/buofuel generator would / could be ran to supply the extended range.

I can certainly see the appeal and I’m quite confident that it is the way the boating market is going to go. (Eventually)

 

[lustyd]

Give examples that have the range at comparable cruising speeds to diesel engined boats. Sure you can have greater range but at lower speeds. When making comparisons all conditions should be equal.

No. You’d dismiss anything I say so it’s pointless. There are plenty of great workable examples but since your criteria will always be based on the status quo you’ll never benefit from them.
Why do you need to go flank speed in mid ocean though?

 

[MisterBaxter]

Reading Eric Hiscock and others, back in the sixties and earlier, small auxiliary engines and small fuel tanks were the norm. I seem to remember Hiscock recommending 1.5 hp per tonne of boat, and describing an ocean cruising 30 ft yacht with a ten gallon fuel tank. The expectation, and indeed the point of the exercise, was to travel under sail, with an engine to get you into a tight berth.
If you were happy with that approach, electric-only propulsion would be fully possible right now. I've cruised a Sonata with a 3hp transom-mounted 2-stroke outboard and had a lot of fun, but it does require a different mindset and there are things you simply can't do.
Apparently the skippers of the old West Country trading ketches used to talk about sailing 'by anchor, tide and teapot' - you can get anywhere if you don't mind taking your time...

 

[dunedin]

[

Reading Eric Hiscock and others, back in the sixties and earlier, small auxiliary engines and small fuel tanks were the norm. I seem to remember Hiscock recommending 1.5 hp per tonne of boat, and describing an ocean cruising 30 ft yacht with a ten gallon fuel tank. The expectation, and indeed the point of the exercise, was to travel under sail, with an engine to get you into a tight berth.
If you were happy with that approach, electric-only propulsion would be fully possible right now. I've cruised a Sonata with a 3hp transom-mounted 2-stroke outboard and had a lot of fun, but it does require a different mindset and there are things you simply can't do.
Apparently the skippers of the old West Country trading ketches used to talk about sailing 'by anchor, tide and teapot' - you can get anywhere if you don't mind taking your time...

True. But a lot of the old boats, particularly engineless ones, did in the end get wrecked due to getting embayed in strong winds, or becalmed in tides too close to rocks.

 

[penfold]

That wasn't a recommendation, it generally wasn't practical to fit larger engines and very often was not affordable; they fitted what was available and affordable, hence Stuart Turner P5s being asked to push 3 tons of boat etc.

 

[Supertramp]

Enormously satisfying to complete manouvers under sail. Hugely reassuring to have an engine in reserve.

 

[SaltyC]

Reading Eric Hiscock and others, back in the sixties and earlier, small auxiliary engines and small fuel tanks were the norm. I seem to remember Hiscock recommending 1.5 hp per tonne of boat, and describing an ocean cruising 30 ft yacht with a ten gallon fuel tank. The expectation, and indeed the point of the exercise, was to travel under sail, with an engine to get you into a tight berth.
If you were happy with that approach, electric-only propulsion would be fully possible right now. I've cruised a Sonata with a 3hp transom-mounted 2-stroke outboard and had a lot of fun, but it does require a different mindset and there are things you simply can't do.
Apparently the skippers of the old West Country trading ketches used to talk about sailing 'by anchor, tide and teapot' - you can get anywhere if you don't mind taking your time...

Completely agree, You CAN! however sailing on a generally lee shore coast it is nice to know I have 55HP under the cockpit floor if all goes wrong. I can push adverse tides and onshore winds if needed! I DO NOT use excessive motor as I prefer to sail, the last time I took diesel was 08/21.
I have never taken 10 hours to travel 22 miles due to wind direction and lack of electric to allow motoring! Yes, that can be attributed to sailing ability BUT it is a very nice comfort blanket.

 

[Tranona]

No. You’d dismiss anything I say so it’s pointless. There are plenty of great workable examples but since your criteria will always be based on the status quo you’ll never benefit from them.
Why do you need to go flank speed in mid ocean though?

Why can't you answer a simple question? I am fully aware of the claims made for the latest electric propelled boats together with the caveats attached to them and how the claims stand up to scrutiny. Hence my scepticism. Nothing to do with defending the status quo, but just reflecting on 40 years of listening to overstated claims and watching products shrink without trace because they could not meet the claims. As the subsequent posts suggest you can have limited range, low speed motoring capability for ocean cruising IF you go back to the days of Hiscock, but the claims today are that you can enjoy all the luxuries of modern ocean cruising boats without a diesel engine. This is not the same as saying that you can cruise oceans solely reliant on electric power generated from wind, solar and regeneration - you can as Uma shows in a rather unsophisticated way but your limitations under power are not dissimilar from those of Hiscock with his Stuart Turner (but without the petrol dribbling into the bilges).

Technology is not yet at the point of jumping to the next level in terms of energy density for batteries. Motors and control systems are probably there.

I have not seen any mad rush to buy the all electric boats that have been designed and built with a view to volume production. Like many new offerings (not just boats) that are "not quite there" you get a few buyers who are willing to take the risk, the demand stops when the more cautious next step buyers see the compromises.

In answer to your last question, suggest you ask people who go long distance cruising how and when they use their engine. It would almost certainly be different from how they would use electric and as suggested would require a different mindset to work within the limitations. Given the very small number of people that buy new boats for long distance cruising it will take a long time to actually establish a new way of operating such a boat.

 

[penfold]

The motors have been available since the advent of electric motors, mechanical controllers more or less the same vintage with reliable and affordable solid state controllers allowing fancy pants function like regeneration available since the 90s; what is still missing is storage with high enough energy density, although lithium chemistry has brought it a lot nearer to competing with internal combustion and they're getting closer every year. In the interim those with deeper than average pockets and boats over 10m could reasonably consider a hybrid system and not lose any real functionality compared to a diesel.

 

[MisterBaxter]

Completely agree, You CAN! however sailing on a generally lee shore coast it is nice to know I have 55HP under the cockpit floor if all goes wrong. I can push adverse tides and onshore winds if needed! I DO NOT use excessive motor as I prefer to sail, the last time I took diesel was 08/21.
I have never taken 10 hours to travel 22 miles due to wind direction and lack of electric to allow motoring! Yes, that can be attributed to sailing ability BUT it is a very nice comfort blanket.

Yes - it's also rather academic these days in that every used boat comes with a fair-sized diesel and there'd be no sense in taking it out, so very few of us are faced with any kind of decision on the matter.

 

[Tranona]

The motors have been available since the advent of electric motors, mechanical controllers more or less the same vintage with reliable and affordable solid state controllers allowing fancy pants function like regeneration available since the 90s; what is still missing is storage with high enough energy density, although lithium chemistry has brought it a lot nearer to competing with internal combustion and they're getting closer every year. In the interim those with deeper than average pockets and boats over 10m could reasonably consider a hybrid system and not lose any real functionality compared to a diesel.

The current state of development is roughly where it was in the automotive world 20 years ago when Elon Musk was converting Lotus Elise to electric power and back street garages were putting electric motors in Morris Minors and FX3 taxis. There was no real consumer demand, just a small number of people happy to pay the high cost of essentially running prototypes on behalf of others. It was only after spending billions and rethinking the architecture of the car that he was able to make the leap ad build a car that was a viable alternative to IC powered cars. Even then only for the very wealthy and it has taken 10 years for this technology to extend down to the mass market and only because of legislation. Even now the cars on offer are not complete replacement for IC, particularly outside the developed world and sell at a premium of 30-40%

The current crop of electric powered new yachts are just like the Tesla Elise. Expensive niche boats that are converted to electric and attract a small number of wealthy owners who are prepared to act as developers of what are essentially prototypes. No builders can afford the costs of building a boat specifically to take advantage of electric power and put it through the sort of development programme to demonstrate its worth and turn it into a marketable mass market product. Multihulls look promising because of their larger surface area and cruising speed potential that allows regeneration. However as has been demonstrated it is possible to build a boat that will sail (and motor) round the world using only its own generated power, it is not possible to do this and also provide energy for the level of living for the size and type of crew that is attracted to this sort of boat in the first place.

Hybrid is a red herring. All the systems available to date are unsuited to sailing yachts under about 45'. Too big, complex and heavy plus offer no real advantage over straight IC power and solar for domestic use. It would only work if there was a hybrid power train like Toyota built for the Prius and they and others have developed that are comparable in size and weight to straight IC. Even then they rely heavily on regeneration and do not produce surplus energy for domestic use. Even the systems that have been used on some multihulls which have large IC generators for both domestic and electric propulsion failed to work in practice.

As I suggested earlier there is unlikely to be any change in this situation until the next leap in battery storage capacity that will reduce the space and weight constraints so that they will fit current boat architecture and provide better USABLE range. There is no legislation forcing the pace, no consumer demand, and as a consequence no funds for R&D. As with all past power developments it will depend on spin off from automotive and industrial developments.

 

[dunedin]

Hybrid is a red herring. All the systems available to date are unsuited to sailing yachts under about 45'. Too big, complex and heavy plus offer no real advantage over straight IC power and solar for domestic use. It would only work if there was a hybrid power train like Toyota built for the Prius and they and others have developed that are comparable in size and weight to straight IC. Even then they rely heavily on regeneration and do not produce surplus energy for domestic use. Even the systems that have been used on some multihulls which have large IC generators for both domestic and electric propulsion failed to work in practice.

Tranona not sure how much research you have done on this, but there are quite a few serial hybrid yachts being built which looks to be an effective solution for “sailing yachts under 45ft” - albeit only for a new build.
Most new build 45 footers for serious long distance cruising these days will have a substantial diesel engine, plus a diesel generator plus a Watt&Sea or similar for doing blue water, plus solar for at anchor. This is not a simple or cheap setup.
Compared with that they may fit say one (or perhaps two) Oceanvolt saildrives, which have variable geometry props which work well in three modes - motor drive, regeneration and low drag sailing (a standard prop doesn’t work well for this).
Combined with a 48V DC generator this can provide extremely efficient motoring at modest speeds for huge distances, and plenty of power with battery assistance for shorter distances (eg to catch tide round a headland or get off a lee shore).
With the standard diesel tanks, the range could be 2-3x the standard diesel engine range. But typically might reduce diesel tankage slightly.

So a well designed serial hybrid is a current serious prospect - but only really for a new build, and on a boat with the inherent speed to make regeneration effective. Hence why things like Arcona, X Yachts and more sporty cruising cats are most common here. The cost premium compared to a fully specced offshore cruiser (ie one getting diesel, water and solar generation) is relatively minor if built from new, and typically less than other options on these boats (such as full teak decks, carbon mast and/or carbon boom and furling sails) which are often ticked by the new owners.