electric Seawind 1000 XL2

[trincomali]

@aybabtme have you collected any more data of W vs SOG? Would love to see it if so.

Do you have a rough estimate of the current displacement of your boat? Internet research suggests around 12,000lbs for that model?

[sailingharry]

Originally Posted by toolbar

I know about the TRT that reverted to burning fossils. But I wonder what the problem was.

I suspect the three major reasons that EP "fails" are:
* Desiring more HP (I left a port this past weekend, and motored at WOT for over an hour, with boat speeds sometimes in the sub-1kt range, much of it in a channel too narrow to even think about beating, and once I set my heavy air blade I had to promptly roll up the shredded remains -- with EP I would have joined the rest of my club back in the harbor waiting it out).
* Desiring more range. Day 1 and Day 3 of the 5 day cruise were 30 mile legs with about zero wind. All of us motored the entire trip those days. EP wouldn't have done it.

* Desiring autonomy. We rarely tie to a dock except at our house. I've gone 6 weeks while traveling over 1000 miles, without a single connection to shorepower. Diesel is cheap and easy to get (a night of shorepower costs as much as 30 gallons of diesel!). Unless the charging sources (regen, solar, etc) exceed the daily EP consumption (and house consumption too! Our solar, wind, and Watt&Sea still need help from our alternator), then marinas are necessary. Some people (a member of this forum who recently converted is an excellent example) tie to a dock essentially every single night, and this is not an issue. Day sailors, in particular, are home every night.



Those that love EP have use cases where none of those items are factors. Those that have those factors to consider cannot use EP. It doesn't mean EP is "bad," it just means that it doesn't work for everyone. And if it doesn't work -- it doesn't work big-time.

[trincomali]

@sailingharry I think you're totally right for most cases. A lightweight catamaran like the Seawind 1000 XL2 in this thread is a bit of an exception, because it really *could* put on enough solar to solve the power, range, and autonomy issues you mention - that is, it has enough raw surface area. You might have to get rid of the mast and sail, though.

As an existence proof, see Electric Philosophy, which is a much heavier boat with narrower beam: https://48north.com/cruising/cruisin...ls-on-the-sun/

[sailingharry]

Originally Posted by trincomali

@sailingharry I think you're totally right for most cases. A lightweight catamaran like the Seawind 1000 XL2 in this thread is a bit of an exception, because it really *could* put on enough solar to solve the power, range, and autonomy issues you mention - that is, it has enough raw surface area. You might have to get rid of the mast and sail, though.

As an existence proof, see Electric Philosophy, which is a much heavier boat with narrower beam: https://48north.com/cruising/cruisin...ls-on-the-sun/

Very nice article! And even in their case, it proves my points.
* A 40' power cat that cruises at 5.5-6 kts (and needs battery to do that). It's very possible, but not every power boater (or many sailors) want to power at under 6 kts. Wonder how that changes with 30 kts on the bow, with seas to match? But, as I stated above, they may simply not go out in those conditions!

* A range of 40 hours without solar. Great if you aren't doing a 300 mile non-stop passage on a cloudy day(s). While I certainly don't do that, I wonder how it handles multiple back-to-back 8 hour days, where net consumption probably exceeds net production (especially outside of the 4 peak production hours?). But again, they may not need to travel 500 miles in 10 days. (I have).

* They have, for their use case, solved the "autonomous" bullet.


My point is that it works for people who want it to work, or whose use-case fits. For a very large number of people, conversion back to ICE is the only solution.


For their boat, there is a HUGE amount of energy-intense materials on board. Without even considering the human and environmental toll, I wonder where the "carbon" break even point is. In cars, it's something like 50K miles (which is great -- the next 200K is just icing on the cake). On a power boat, it may well be only a few years. On sailboats with much lower consumption, it's likely much longer.

[Symphony]

@sailingharry your experience and analysis of use cases is spot on. I can see a day in the near future when boats with electric propulsion will need to depreciate enough to justify refit with a diesel propulsion, given the relatively short life of battery storage, a life cycle that is mismatched to the lifecycle and useful life of the rest of a quality FRP vessel.
You mentioned paying >$120 (30gal diesel) for overnight electricity. Where was this? My experience is a shorepower charge of $0-$25 per day. Or maybe you include the cost of a slip overnight? That would be cheap for your boat length.

[sailingharry]

Originally Posted by Symphony

@sailingharry your experience and analysis of use cases is spot on. I can see a day in the near future when boats with electric propulsion will need to depreciate enough to justify refit with a diesel propulsion, given the relatively short life of battery storage, a life cycle that is mismatched to the lifecycle and useful life of the rest of a quality FRP vessel.
You mentioned paying >$120 (30gal diesel) for overnight electricity. Where was this? My experience is a shorepower charge of $0-$25 per day. Or maybe you include the cost of a slip overnight? That would be cheap for your boat length.

Yes, the total cost of spending a night in a marina just to top up batteries. About $3/foot, 43 feet (math is easy -- at $4.30/gal, that's 30 gallons!), plus the $5 typical power fee. I usually swing on my own anchor.


But I should reiterate, there are use cases where it makes a GREAT deal of sense.

[Symphony]

@sailingharry yes, there must be a good use case for battery propulsion but I have yet to find it. My experience: ran fleet of 3 heavy-duty robomowers using AGMs, as well as personal and captained boats up to 65' most with large batteries banks using alternators, gensets, shore power and solar panels.

The mowers seemed good, discharge to 50% SOC was enough for full mow-cycle followed by 48+ hours of smart charge, but after exceeding number of lifetime charge cycles the second time of Digi-Key AGM batteries (high quality) I realized the cost was enough to hire the local guy to mow the lawns, plus I spent plenty of time fussing with SOC and charge level so as to maximize battery life.

I am disabled so my latest use case was to be a 20' old-man daysailer. I have 20 minutes trip out of crowded marina and inner harbor each way, and thought battery boat would be perfect, no diesel/oil/trans/coolant fluids to handle, with shore power to recharge every night - battery propulsion should be perfect. I looked at 5-10 year old boats with all manner of battery inboards and outboards - but after 6 or 7 years of use they all needed batteries replaced, and even the motors were in not good shape. the controllers were often funky just from sea-air corrosion - and this is short season North East usage.

the thought if hiring a gorilla to remove and reinstall battery pack, plus reprogramming controller or maybe motor was frightening. When I calculated energy needs for my day sail if the current was foul or the winds opposing I found things could be dicey. If adding battery capacity the excess weight would make the boat a pig in the waves.

After a lot of realistic number crunching and investigation with current users and marina techs, also thinking about how much of my boat-time previously was spent managing battery banks SOC (it's a lot of money in those, so you can't screw it up by under or overcharging!) - I realized 1. the maintenance time/worry is greater for battery than for diesel 2. Over a 10-20 year useful life of boat, the cost of battery power is ridiculously higher than simple diesel. Heck, even Tesla cars are only required by EPA to have a 8-10 battery life.

My current boat has 14hp Beta which is plenty power to escape sudden onset of squall and foul current. It burns 0.25 gal/hour to push me at 4-6kts. The engine will easily serve 20+ years and still be good, and I almost never need to check the single AGM SOC. I love the quietude of battery propulsion, so I sail as much as possible, even into the harbor when breeze is fair.

That's my 40 years of experience. YMMV.
thank you for your postings, as I still hope battery propulsion may work someday.