Electric inboard engine, equivelant diesel inboard.

[ylop]

It's not a technical issue, it's just unnecessary. Charge times aren't that long and range allows for driving longer than is safe anyway.

I have an EV so understand that argument, it’s mostly accurate for Motorway driving BUT if I want to leave motorways I start to get away from super fast chargers (my car can do 80kW but some motorway chargers do 150). In rural areas I’m delighted if I come across a 50 but 22 or 7 are more common. That suddenly makes recharging a chore if you are midjourney. On a motorway my battery goes from 40% to 80% in the time it takes to go for a pee, buy a coffee and check the headlines. On a 7kw charger that would take a 3hrs. My main issue is actually turning up and discovering them occupied or broken though. Theres no reason every petrol station (or corner shop) couldn’t have a rack of suitcase sized batteries that are trickle charged and swapped as needed perhaps adding 20% to my range? You wouldn’t need one all the time just on longer or more remote journeys. And my car is fairly big battery - other people who have “commuting” sized batteries but need to make an occasional long journey might appreciate it more. My most irritating journey is to do something like drive 100 miles and climb a mountain - then drive 100 miles home. It starts to get close to range anxiety point (especially in winter) but my parking spot will not have even low power charger and a 90 minute journey isn’t really worth splitting.

It's also unnecessary to put batteries in the keel, there is plenty of space on most boats for sufficient battery storage, especially once you remove the diesel tanks and associated pipes, filters and other paraphernalia.

I’m not suggesting it’s necessary but sticking a load of lead down there seems silly if there’s a big heavy thing to lug around anyway! One downside of not having diesel (for those of us in northern climes) is lack of heating and the “free” hot water we get from the engine. Those domestic loads will be quite expensive in terms of battery capacity - and are perhaps most in need at times of the year when any solar is least likely to compensate and shorter daylight means people may be sailing less so have fewer regen hours.

To be clear, I’m no flat earther, I’m just of the view that a step change in E-boats needs a radical move by a builder (existing or distruptive) to force them to make E-boats rather than offer diesel boats with an E alternative.

 

[lustyd]

I’m not suggesting it’s necessary but sticking a load of lead down there seems silly if there’s a big heavy thing to lug around anyway! One downside of not having diesel (for those of us in northern climes) is lack of heating and the “free” hot water we get from the engine. Those domestic loads will be quite expensive in terms of battery capacity - and are perhaps most in need at times of the year when any solar is least likely to compensate and shorter daylight means people may be sailing less so have fewer regen hours.

To be clear, I’m no flat earther, I’m just of the view that a step change in E-boats needs a radical move by a builder (existing or distruptive) to force them to make E-boats rather than offer diesel boats with an E alternative.

Sorry wasn't calling you a flat earther just a comment on how these threads go, you can put all the info out there but some people don't care, they know their truth.

The trouble is mostly the lead is in a bulb at the bottom, and lead is considerably heavier than LiFePo4 as demonstrated by battery weights for equivalent sizes. I think we probably will eventually see electric specific design elements but I don't think they will be what people expect. One example is the boat using two smaller motors so they fit under the bunks and generate more power than a larger single. I suspect we'll also see more divergence between racing and cruising. Race rules have affected design for decades, usually not for the better, and this may well change so cruisers can get what they need in the boat.

 

[Tranona]

You forgot to start this with in my opinion. Quite useful when you're navel gazing and speaking for others who may well completely disagree

No. I am quoting direct from the testimonials on the oceanvolt site - which you do not seem to have read. I have read almost all the 150 testimonials from owners and builders of boats fitted with oeanvolts system. This means that when I post observations they are not my opinions but come from a reliable source. Exactly the same as the ranges I quoted which come directly from oceanvolt published material or again from owners' testimonials.

 

[Tranona]

Sorry wasn't calling you a flat earther just a comment on how these threads go, you can put all the info out there but some people don't care, they know their truth.

The trouble is mostly the lead is in a bulb at the bottom, and lead is considerably heavier than LiFePo4 as demonstrated by battery weights for equivalent sizes. I think we probably will eventually see electric specific design elements but I don't think they will be what people expect. One example is the boat using two smaller motors so they fit under the bunks and generate more power than a larger single. I suspect we'll also see more divergence between racing and cruising. Race rules have affected design for decades, usually not for the better, and this may well change so cruisers can get what they need in the boat.

You really are behind the times with your speculation. Once again read the link I posted where you will find there are already designs that use 2 small pods instead of one large one, and have design features that would not be possible without electric propulsion. The divergence between racing and cruising is again already happening. Rating rules do not discriminate between different methods of propulsion - only in terms of the type of propeller. However as most racing boats irrespective of power source use folding propellers this is irrelevant. Most of the smaller racing classes are effectively day sailors so range is less of an issue.

 

[Trident]

I would love to see an electric yacht motor for hundreds of miles at a time

The hugely expensive and top of the range Silent Yacht cats with huge real estate for solar etc cannot manage even a hundred without the generator

The electric BB365 with twin OceanVolt and lots of Victron LifePo and all the whites and bells in a light weight cat (and a £100K price tag for all the electric kit set up by Ocean Volt for the company ) makes about 40 before the generator kicks in (and IIRC correctly thats at maybe 6 knots)

There are many people who use electric to get out of the harbour and back again and then leave it to charge all week and that's great. There are many people who have circumnavigated with no engines at all and I'm in awe of them. For me, long term cruising I was given two absolutes by my wife to be happy to come with me : 1) at least 12 hours motoring capacity at normal speeds (6 knots for us on a 50 foot cat is slow but thats what we agreed as normal) in normal conditions (so allow some time with wind on the nose - or why motor - and some against tide and 2) at least 4 hours of full power full speed against heavy weather for an emergency

At any cost with current equipment in 2018 I could not find any set up that would allow this electrically. A pair of Yanmar with just 50 litres of fuel would do so

 

[lustyd]

I would love to see an electric yacht motor for hundreds of miles at a time

Well Oceanvolt's estimator says my boat (SO36.2) would have a range of over 100 miles at 4kt even with their relatively small battery capacities. The problem is that they always quote the faster speed so give ranges in the order of 50 miles. That doesn't mean your range is actually that low. Watch Uma and look through their stuff on the Patron Discord, it's not that hard to achieve with the right attitude.

 

[Trident]

Well Oceanvolt's estimator says my boat (SO36.2) would have a range of over 100 miles at 4kt even with their relatively small battery capacities. The problem is that they always quote the faster speed so give ranges in the order of 50 miles. That doesn't mean your range is actually that low. Watch Uma and look through their stuff on the Patron Discord, it's not that hard to achieve with the right attitude.

I know directly from Oceanvolt that they could not achieve that with a £100K spend from a recent customer on the cat I mentioned earlier. Huge Victron lithium bank, all the controllers and weeks of optimising charge etc and a customer having this done from the factory on his boat with the attitude that he would accept the cost and the inconveniences but as a true eco-pioneer he could not accept diesel engines (though was convinced for safety to have a generator back up) .

The best figures OV do are with tide and no wind against them etc - in the real world this cat could manage 4 hours at about 6 knots until we added another 1500w of solar to the existing 2kw (and it had re-gen of course) and then it might do 5 hours on a sunny day - so 30 miles. Perhaps at 4 knots 45 miles. Now full disclosure - I think the generator was set to come on at 25% battery for safety so before the BMS shut it down he could probably have got 1 more hour out of it - 4-6 miles - but this was a complete brand new system specified in 2020 by OV themselves , that cost £100,000 and countless hundreds of hours including OV factory fitting it and then IIRC two later visits to the UK to fine tune the set up as well as multiple solar tweaks by us (changes in series and parallel etc to find the real world max input for that boat)

I have huge admiration for the owner and he is making it work for his style of limited cruising and of course at the end of the day has the safety back up of a diesel generator if things get dangerous and power is low but I just can't see it yet for a long term cruising boat unless you're very specific on the location you cruise.

 

[Tranona]

Well Oceanvolt's estimator says my boat (SO36.2) would have a range of over 100 miles at 4kt even with their relatively small battery capacities. The problem is that they always quote the faster speed so give ranges in the order of 50 miles. That doesn't mean your range is actually that low. Watch Uma and look through their stuff on the Patron Discord, it's not that hard to achieve with the right attitude.

That is nothing new - the lower the speed the greater the range equally true for diesel engines (and electric cars!) and that the loss in range for increase in speed is greater with electric power.

The reality is that real life use is very different from just picking spot figures for speed/range. That only gives you the parameters that you have to work within to see it it matches your desired pattern of usage. Perhaps if you had read the testimonials you would have discovered how different owners have done this.

For example this oceanvolt.com/testimonials/contessa-34/ is a good example of a boat similar size to yours. He explains how he can operate the boat well within the limited battery capacity (even smaller than the normal oceanvolt packages). Note also the amount of additional equipment needed to make it work. I will leave you to decide how this pattern of usage matches up to the way you use your boat and the capability of of your diesel engine. BTW don't forget that just the power unit costs £25k retail.

 

[dunedin]

Well Oceanvolt's estimator says my boat (SO36.2) would have a range of over 100 miles at 4kt even with their relatively small battery capacities. The problem is that they always quote the faster speed so give ranges in the order of 50 miles. That doesn't mean your range is actually that low. Watch Uma and look through their stuff on the Patron Discord, it's not that hard to achieve with the right attitude.

There’s more to this than just watching YouTube films. And I have studied Sailing Uma’s various iterations, including two versions of the Oceanvolt saildrive (I guess they did not pay real money to replace the first within a year). Also done the maths with their battery size (at least as was a year ago) and no way they have a realistic range of over a hundred miles.
Also don’t forget most range figures are flat water, no wind and no tide. I have also seen the maths on impacts of headwinds and waves. Have you?
Some articles last year in CA Cruising magazine on this topic.

 

[lustyd]

Also don’t forget most range figures are flat water, no wind and no tide. I have also seen the maths on impacts of headwinds and waves. Have you?

Sailing boats don't need to motor in windy weather, they need to motor in calm and flat conditions.

 

[SaltyC]

Sailing boats don't need to motor in windy weather, they need to motor in calm and flat conditions.

Unfortunately, tacking along a coast against a 2+ knot tide and waves results in a GPS tacking angle of 160 degrees and not a lot of progress.
Before we get the cry of 'bad planning ' etc Sod's law of the sea causes delays and all 3 sheets of passage plans to go with the wind, plus a small ICE engine coupled to a folding 2 blade eggwisk unable to motor and push through the sea (Me) or poor passage planning and an electric motor with insufficient range to motor cause a 8 hour passage for remaining 10 miles.(Not me)