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sunchaser said:
How do the batteries get charged so you can easily knock off 175 miles in 24 hours including night in a 20 to 50 ton monohull?
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Can't do it in a 20~50t mono. First you need to crunch the numbers for hull efficiency at different speeds, and depending on the size of your propulsion battery bank, determine what speed would allow a 175 nm non stop run.

Using the numbers I have already crunched for the Aspen C90 power proa 28' at 8500 lbs with a 36.4 Kw-hr lithium bank, your speed would be 3.8 kt to cover those 175 nm non stop. With 1900 watts of solar, you would need 4 days on the hook to fully recharge for the return leg.
 
rjtrane said:
It's easy to dismiss this technology by setting the goal posts outside of the stadium. QUOTE]

Not in my 30 ton stadium. So what I have to do is sell my nice comfortable trawler, move to a sunny southern climate near the water, and boat in an expensive small cat? Without AC?

I admit, the idea is intriguing, now to sell my skiis! FL here I come :dance:
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Different strokes for different folks. For me, being a sailor and on the fence as to the next boat being a sailboat or powerboat, the freedoms of a diesel-electric, solar assisted powerboat are inviting. Upwind without tacking, modest propulsion speed without fuel usage, and with the current state of battery technology and price drops, doable now.
 
Why sell your trawler and move south? Nobody has suggested you do that. Burn all the diesel you desire. Last I checked nobody thinks its a crime.

My low speed electric car will never be a big hit with most folks due to its limited speed and range. In our environment and for our lifestyle it works fine.

Likewise low speed electric boats will never make sense if it doesn't fit your lifestyle and environment. Horses for courses, if the horse won't run your course why would you want it regardless of price?
 
I can understand why you don't want to give up your 30 tonner. The largest trawler we built was 80 tons and life aboard was quite pleasant. We all cried when she was sold. Botn the Key Largo, Billy Joel renamed her Red Head. Even with cheaper diesel, filling up her 2,500 gallon fuel tank took a swipe out of our MasterCard. That boat was no candidate for pure e-power either.

But, had the technology existed at the time, 1988, she would have been a candidate for hybrid electrical system for hotel loads and even short range, limited speed e-power (using a parallel system). It would have kept down the hours on her pair of 20 kw generators.
 
Reuben,
You have enjoyed some unique boating circles. For that, I trust your perspective. My background is limited in comparison. Started as a kid with the family's Flying Junior and other boats of friends, then my Cal 40 and finally commercial ships, with the last one the smallest at 32,000 ton displacement and diesel-electric propulsion. Do you think you will be going forward with the extending ama, diesel-solar-electric cruiser in the sub $300K range?
 
CPseudonym said:
low speed electric boats will never make sense if it doesn't fit your lifestyle and environment. Horses for courses, if the horse won't run your course why would you want it regardless of price?
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Good point. I really can't justify the costs of the changes I'd like now, but in the next two years, my style of cruising will fall into parameters that may make an electric hybrid a good choice. Meanwhile, battery tech improves as does consumption rates of motors and appliances. Sunshine has everything I need right now in a cruising boat except the ability to take Florida sunshine with it wherever it goes.

The reason I'm eyeballing the Aspen asymmetrical cat is because I really like the idea of a design which one could use a bracket-mounted dinghy motor as a reasonable, controllable get-home option, as the boat is intended for a single power plant anyway. The Buzzards Bay is a dream boat (may be a better platform too), but would probably need twins for performance sake. No doubt that it could be a real hybrid contender, but the extra cost is only worth it if one enjoys the performance assets it delivers as-is. I think Aspen is already manufacturing the most economic, reasonable, sale-able platform for a hybrid experiment right now. A close second could be the equally spacious, Polish-built MotorCat 30 which was reported to reach a 10 knot cruise with twin Merc. 9.9's in a UK test, and can be had for something over 110K without the 50 HP outboards they typically wear. I don't know jack about marketing strategy in boats, but the hybrid or electric designs are still pretty exotic. The richest guy I know has a Prius, but his other car is a Rolls Royce. Both are toys.
 
Last fall a couple stopped at the marina with a home made cat, after spending 14 years building it they were on their maiden voyage to Florida. It was I'am guessing 18' beam & 34' long, power was 2 Mercury 20 hp outboards, in talking with them I learned they were getting 8 mpg. This was with the current at the time in our pool of about 1.5 mph. Once in Florida they were going to buy a mast, sails & rigging. I can't see the benefit of electric power with the cost of associated components when these results can be had with a couple of dependable old school Merc outboards used with the proper hull if your goal is economy in a powerboat. If the goal is a powerboat with 0 carbon footprint then I can see electric as a logical choice.
 
healhustler said:
Good point. I really can't justify the costs of the changes I'd like now, but in the next two years, my style of cruising will fall into parameters that may make an electric hybrid a good choice. Meanwhile, battery tech improves as does consumption rates of motors and appliances. Sunshine has everything I need right now in a cruising boat except the ability to take Florida sunshine with it wherever it goes.

The reason I'm eyeballing the Aspen asymmetrical cat is because I really like the idea of a design which one could use a bracket-mounted dinghy motor as a reasonable, controllable get-home option, as the boat is intended for a single power plant anyway. The Buzzards Bay is a dream boat (may be a better platform too), but would probably need twins for performance sake. No doubt that it could be a real hybrid contender, but the extra cost is only worth it if one enjoys the performance assets it delivers as-is. I think Aspen is already manufacturing the most economic, reasonable, sale-able platform for a hybrid experiment right now. A close second could be the equally spacious, Polish-built MotorCat 30 which was reported to reach a 10 knot cruise with twin Merc. 9.9's in a UK test, and can be had for something over 110K without the 50 HP outboards they typically wear. I don't know jack about marketing strategy in boats, but the hybrid or electric designs are still pretty exotic. The richest guy I know has a Prius, but his other car is a Rolls Royce. Both are toys.
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I have to tell you your research is more thorough than mine, the MotorCat 30 is another very high efficiency hull, I had fun crunching its low speed power consumption numbers because since it is set up for outboards already, the conversion is simple with the AquaWatt outboards. http://www.all4solar.com.au/AW_BROCHURE_EN_2012.pdf
 
River Cruiser said:
If the goal is a powerboat with 0 carbon footprint then I can see electric as a logical choice.
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Speaking for myself only, the carbon footprint is a nice side benefit for conversational purpose only. I'm not some closet greenie regardless of how my recent posts may make me look to others.

My primary interest is in nearly silent propulsion. Hold over from my previous life with a manufacturing company that did R&D and retrofit work in that field for the US Navy. An area of personal interest of mine that dovetails nicely into my current boating hobby and passion for small electric vehicles.

I'm also a devout tinkerer with a curious nature that enjoys figuring out either how stuff works or better yet, how I can make things work.
 
"Upwind without tacking, modest propulsion speed without fuel usage, "

No chance , a boat that "cruises at 3K in very still water will hardly go "up wind" at ALL!

Contemplate the speed of advance in a 20K-30K sailing breeze with 4-5 ft short waves!!!
 
An interesting thread. Converting my house bank from golf carts to LiFePO4, I have become a fan of the EV movement. I have also sort of toyed with the idea I might be able to covert my boat to a diesel electric hybrid. But I'm doubtful it could be cost justified. At least yet.

Solar could potentially essentially eliminate my generator run time for running the "hotel", but it's not going to solve the propulsion problem on long runs. The hope would be in places like the BVI or the San Blas, you could store enough energy over several days for 2-4 hour hops between islands on the batteries alone.

In the last 2 years, we've travelled from Florida through the Eastern Caribbean to Grenada, then west via the ABCs and Colombia, then the Western Caribbean to Honduras. At the 2 year point, we have spent $15,601 on fuel. This includes 2130 generator hours, dinghy fuel and propulsion fuel for the trip to date with fuel averaging just under $5 a gallon. Call it $8000 a year and represents just 13% of our cruising budget. We do operate at 5.5 to 6 knots to conserve fuel and average at least 2 NM/Gal.

So let's assume for some reason my 6000 hour Lehman's need to be replaced. New ones are probably around $25K each installed. So that's 50K. The battery bank alone for my design thoughts would be 50K. Then you need to add the motors, controllers and at least one hefty genset. That's at least another 50K, probably more with the engineering changes to make it all work. So we are up to probably a minimum of $100K for the conversion, probably an optimistic assumption. Then add in 10K for a solar system. So it's 50K for diesel propulsion, 110K for a hybrid with a 60K differential.

This could potentially shave 50% off my $8000 annual fuel costs. But at $4000 in savings a year, it's gonna take 15 years to break even, perhaps a little less as diesel fuel continues to rise in price.

Anyone see any flaws with this analysis?

I think the clean sheet designs are probably a more practical solution. But they have to compete not only with other new boats, but the used market where 150-250K can get you a lot of boat.

But the fundamental flaw is a guy buying a new boat has the money where in his budget, fuel will be less than my 13% of total expenditures, maybe only 7-8%. Or OK 13% if he wants to do 8-9 KTS. So you have to compete on all fronts, fuel is just not a deal maker by itself. And a budget minded fellow is going to buy used and do something like I did, or heavens forbid, buy a sailboat.
 
Last edited:
New DSe 12m w/Amas

Bob,

Current plans are to tow the model (once the original DSe has new parts installed for e-drive) and get the resistance data for speeds up to 15 knots. Once the HP/Speed curve is calculated, then I'll have a better idea as to projected speeds and efficiency. If we expect to meet our goals, then we'll consider a full-size prototype.

We never conceived this new version as ocean-crossing-capable - but perhaps there would be interest should we choose to go that route. Means some serious rethinking. Right now, she is essentially a glorified pontoon boat with relatively low freeboard - soft sides above waist level - walk around side decks between the amas and the main hull that are fairly close to the water.

Most likely, we could make her ocean capable - since the walk arounds fold up for trailering/shipping - one could flip them up in heavier weather, allowing seas to pass by unrestricted. Likewise, the soft sides could be replaced with hard - more work getting her ready to trailer/ship, but structurally more sound. The canopy is 100% PV glued to a framework and acting as the roof.

The idea of using HDPE may not be viable either - weight could be the issue - a bit of a "pipe" dream (pun intended). Perhaps cold molded or foam-cored - if we were to leave behind the HDPE concept, then we can reshape the entry and exit to the hull (and amas) since we will not be using flat sheets in conical sections. This would make her a bit more slippery, too.

Here's a couple of photos of the model.
 

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So let's assume for some reason my 6000 hour Lehman's need to be replaced. New ones are probably around $25K each installed.

A different brand , a truck take out like an International DT 360 or 466 would be about $3,K has SAE bellhousing to match up easily, and mechanical or electric injection is your choice. Water cooled exhaust manifold if you want woulssadd about $2k as they are fairly custom.

Its still vastly oversized for slow cruising , but the price is right , and the construction/longevity worlds away from the Ford econo Power.

DIY a pair and save almost $40K , thats a lot of diesel!
 
FF said:
So let's assume for some reason my 6000 hour Lehman's need to be replaced. New ones are probably around $25K each installed.

A different brand , a truck take out like an International DT 360 or 466 would be about $3,K has SAE bellhousing to match up easily, and mechanical or electric injection is your choice. Water cooled exhaust manifold if you want woulssadd about $2k as they are fairly custom.

Its still vastly oversized for slow cruising , but the price is right , and the construction/longevity worlds away from the Ford econo Power.

DIY a pair and save almost $40K , thats a lot of diesel!
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The Lehman engines are close to 15K I think? I allowed extra for the installation since I don't have all the cranes and so forth to do it myself. Except for the genset, I think the electric power train would be light enough in pieces to move around?

I would also consider a remanufactured Cummins 6BT normally aspirated, but I have no idea the cost of those. The manifolds are available. No way to do a dry exhaust without a major project.

But Econo Power or not, my engines I think we're made in 1982 and sat around awhile before install. Still running well over 30 years later. Not too bad?
 
Mastervolt won the inovation price 2013 in The Netherlands with their Water cooled Drive Master Ultimate. They have a line of products from 2.5 kW to 100 kW.

Mastervolt/Bell Marine
 

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Aboard the drilling rig "Paul Wolff" operating off the coast from Macae, Brazil, drilling for Petrobras we used an ROV that employed a 100 hp electric motor. Aboard the drill rig we had a lot of typical 480 VAC, 100 hp motors that weighed 800 lbs and were 34" X 22" but air cooled. The ROV's 100 hp motor was about 12" by 6" and because it was both water cooled and fed 6000 volts, weighed about 80 lbs.
 
deckofficer said:
the MotorCat 30 is another very high efficiency hull, I had fun crunching its low speed power consumption numbers because since it is set up for outboards already, the conversion is simple with the AquaWatt outboards. http://www.all4solar.com.au/AW_BROCHURE_EN_2012.pdf
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Whoa! I didn't know about that outboard. What would the outboard system for that weigh? Even though the outboard would fall right on to it, the open hulls of the Motorcat 30 on the inside (just optional bunks thrown into the space) would be nice for a straight-through transom motor like the Mastervolt. Inboards on these things have been talked about and last time I checked, were available as an option. Frankly, I think the boat would be pretty noisy with inboards, but electric......ah!

Craig...I'm with you on your semi-green attitude. I just want silence, but silence in the creeks and bays of the gunk holes that are far too shallow for sail.
 
healhustler said:
Craig...I'm with you on your semi-green attitude. I just want silence, but silence in the creeks and bays of the gunk holes that are far too shallow for sail.
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Finally, someone who "get's" what I'm after. :flowers:

That's precisely why I started the thread to study the feasibility of applying some of this gee-whiz electric technology to my Owens a couple weeks ago.

I will have an electric boat to gunk hole the Delta in eventually but it won't be my Owens.
 
healhustler said:
Whoa! I didn't know about that outboard. What would the outboard system for that weigh? Even though the outboard would fall right on to it, the open hulls of the Motorcat 30 on the inside (just optional bunks thrown into the space) would be nice for a straight-through transom motor like the Mastervolt. Inboards on these things have been talked about and last time I checked, were available as an option. Frankly, I think the boat would be pretty noisy with inboards, but electric......ah!

Craig...I'm with you on your semi-green attitude. I just want silence, but silence in the creeks and bays of the gunk holes that are far too shallow for sail.
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Yep, standard offering is a pair of 50 hp gasoline outboards. That is why I gave the link for the Aussie built AquaWatt electric outboards. Nice thing about outboards, no thru hull fittings and can be power tilted right out of the water for reduced drag when running on one motor, or beaching, plus less crud will grow on the lower units.
 
I'm also considering going electric when the old raw water cooled Volv0 finally gives up on me. Hopefully I'll get a few more years out of her and the price of batteries will come down a bit. Meanwhile I'm getting great info out of threads like this. Thanks guys.

I see a number of advantages to going electric;
1. Silence - It is golden. The old Volvo is fairly rattley and I wont miss the noise at all.
2. No fumes. With the wind on the stern, often there's enough exhaust fumes to make those prone to seasickness feel a bit queasy.
3. Maintenance. My engine is only accessible from above, and I currently spend far too much time with the blood rushing to my head and my butt in the air.
4. No fuel issues. No air in the system, No filters. My stainless steel tanks are 30 yrs old and I expect are also near the end of their life.
5. I also like to align my actions with my morals. I like to think I respect this planet, but sending a cloud of blue smoke up when I start the engine on a cold day doesn't make me feel good.
6. Fuel costs are the least of my concerns as I don't plan on any circumnavigations in my boat. Still - I am expecting a substantial jump in fuel costs over the rest of my lifetime. $20/gallon wouldn't surprise me. (I've spent over 30 yrs in oil exploration and have a fair idea whats left to burn)

Looking at those Aquavolt inboards - they appear to be a good match for my boat. (35hp peak compared to my 36hp Volvo). I'm wondering about their prop size recomendations though. They suggest a 12-14" prop (max 2500rpm), whereas I currently run a 17" x15 pitch (max 3000rpm). Something doesn't add up there.

I am glad to see more options like this every year. Not for everyone - but like all (most) boats, it matches the wants and needs for a percentage of us.

BTW- heres another link to an electric motor/sail hybrid with a twist.
solarsailor.com/
 
AusCan,

Is your present diesel running through a reduction transmission? Might explain the different pitch recommendations. My choice is always to run the largest diameter and deepest pitch if I'm using a reduction transmission, and just choose the gearing to allow full rpm from the engine without over revving. A large slow turning prop has less slip and is more efficient. My prop rpm direct drive on the ships I served on was 113 rpm at full ahead sea speed.

An advantage you didn't mention is all available torque at 1 rpm with a smooth and linear transition from forward to astern. No more clunking in and out of gear for docking.
 
but silence in the creeks and bays of the gunk holes that are far too shallow for sail.

Google "Centerboard"
 
Bob- Your right. I've got a 1.5:1 reduction box. It's me that's not adding up.


Fred - My boat has a full length keel with a 38 inch draft so I'm not overly limited in access. The gaff rig allows a shallower keel, by keeping the centre of force lower.
 
FF said:
but silence in the creeks and bays of the gunk holes that are far too shallow for sail.

Google "Centerboard"
Click to expand...

Tacking in a slough might be your idea of fun but not mine. Try doing it on a windless day and let us know how far you get.
 
An outboard can be the simplest, most economical e solution. I am planing on testing a pair of 4kw Torqeedos on Sunshine one day.

However, for a slow speed boat, those small props are not at all efficient. Especially a heavy slow boat.

I like the idea of steerable pods. Prop and motor turn at the same slow RPM - nothing lost to gear boxes.

If your boat has inboard running gear, then a slow motor coupled directly to the shaft once the old inboard has been delegated to mooring duty.

If you boat has a sail drive you have two options short of tearing it out. 1) use a higher speed motor (less money) and keep the gear box. 2) remove the gearbox and mount the motor vertically with direct coupling to the sail drive shaft.

Sunshine can cruise at 5 knots using a total of
8.5 kW. This is less than 12 HP. And, we are going through an old technology ZF gear box and sail drive. I'm sure we are losing no less than 15% because of the drive train.

The same 5 knots on Sunshine burns 1.2 GPH total at 1,250 RPM. One of you diesel whizzes can calculate that into HP?

In other words, don't try to replace your 30 HP diesel with a 30 HP e motor. Cost and battery will be unreasonably expensive.

I am glad to see that many are confirming that e power is not only an economic issue but quality of life aboard. The silence is overwhelming. Plus, I love all the stares I get when I roam into a "no internal combustion motor" area in Pennecamp with my 39'6" "thirty-something" Sunshine!
 
Reuben,
Torqeedo does offer (3) different pitch props, v8, v30, and the standard v19. Because these props were designed for electric, they do not give the pitch in inches, but the v number represents full rpm speed in kmph, so just divide the v number by 1.64 and then divide the result by 1.15 and you will have the speed at full rpm in kt.

Standard v19= 10.1 kt
High speed v30= 15.9 kt
High torque v8= 4.2 kt I would think this prop would push Sunshine at the motor's full rpm, thus 4.2 kt.

As to crunching the hp numbers of 5 kt at 1.2 gph and 1,250 rpm, you already did with the input power of 8.5 Kw in the preceding paragraph.
 
FF said:
but silence in the creeks and bays of the gunk holes that are far too shallow for sail.

Google "Centerboard"
Click to expand...

That sounds like a reasonable solution, but at least for the majority of the silent cruising we're talking about, overhead clearance in a canopy of green can be an issue on the inland rivers we love, while at the same time, deck height above the water is preferable to see obstacles and underwater growth.

We have a good, shallow, easy to push platform in the Manatee to do this. Even an electric kicker outboard of 20 hp may do the trick
 
I have posted before on diesel/electric hybrids. I spent a lot of time with a boat designer, several marine electrical systems engineers and some engineers from Siemens looking at the effectiveness/efficiency of a hybrid system. In short, the conclusion is that if fuel efficiency or substantial fuel saving is the goal, that goal cannot be met to any significant degree in current full displacement hull designs. The reason really breaks down quite simply. It takes a specific amount of energy to move any given hull at a given speed. That amount of energy is fixed for that hull, it cannot be made variable. The source of that energy is immaterial. For instance, we designed a 57' hull that could operate efficiently at 7-9 knots using about 175 HP. We calculated that house loads, including AC, would require a 20kw generator. Wrapping all that together, in a single engine (driving 2 shafts) installation, 145KW was required which called for using a 6 cyl, 228 HP Lugger. That setup produces 145KW, 60hz at 1800 RPM. The entire system was designed as Rueben earlier described, completely isolated, run entirely through inverters. There were a few benefits to this system, chief among them, a single diesel, rather than three (2 propulsion, I genny), although we looked a second smaller diesel as a backup, ability to place the engine anywhere (decreasing mechanical space and increasing living space substantially), ability to place the engine in its own sound box to almost eliminate engine noise. There were some fuel savings by virtue of having a single larger diesel running at a constant speed rather than 2 smaller one, but in general. the savings penciled to less than 10%.

As far as using the boat on electric power alone, for that hull, we could not calculate more than about 45-60 minutes under electric power with a very substantial battery bank (I don't remember the exact AH).

This is the main reason the hybrids, especially conversions, are not cost effective and I don't see them becoming effective. The saving are not substantial enough for builders to build many new hybrid systems although there are a few on the market.

I agree the future will bring eboats, but they will be designed from a white sheet of paper as Reuben is doing and they will find a market that will start very small (as does every new idea) and will gain acceptance over time as solar technology improves, as storage capacity and efficiency improves and as buyers become more accustomed to having the option.
 
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