Electric Boat

For a project like this I would to to my local motor rewinder for recommendations. Once you get into a project you will want local support. There's nothing worse than investing in a motor and then finding out you can't get controls, batteries, or technical help. I have a perfectly good 18 volt motor that I can't use for anything just because of these problems.

Do a Google search fo EV parts. You should find several sites like this one...

http://www.electricmotorsport.com/store/ems_ev_parts.php

which should have the parts you want/need.

The electric boat world has made a lot of progress in the last few years. 48 volt DC motors of the size range you are looking at are readily available with all the requisite controls. They are not cheap, but then a displacement hull that can use all of 10hp to reach hull speed is not a cheap project either. Go do some searching on the internet. Also there is an electric boat Yahoo group. Join it and spend a few evenings studying the posting history and you will find a lot of your questions answered.

Ed Weldon

You didn't specify the voltage you are already considering, so no one can tell whether a different voltage would be better. 10 HP = 7.46 KW. If we assume 48 V, as reasonably suggested in one post, 7460/48 = 155.4 amps. Multiply this by the number of hours between battery recharges, and this will give you the amp-hour capacity needed for the battery selection--plus you will surely want some reserve. The numbers you have given compare pretty well to a forklift application, and thus you might get good information from a forklift manufacturer. In any event, it looks as though you will need a rather large battery, but even so it may be economically reasonable.

Open sea? Closed Sea/harbours with tidal flows? Fresh water lakes? Canals? Rivers? Speed required? Weight of boat? Hull type? How much are you willing to spend?

Have you any idea at all as to what you want to do?

All of the above questions need to be answered before we can give any reasonably accurate help......surely that must be obvious to you as well?

Larry

Why don't you check these guys out. They have an electric outboard equivalent to a 10hp gasoline outboard.

Larry , Torqueedo is a good outboard but the required battery bank may prove to be the killer. I got involved with one design where we ended up with needing 1500 pounds of battery bank and the cost of such effectively killed the project.

Odyssey is great for thin plate technology but costly. At this time unless you have really deep pockets, forget about lithium Ion type batteries to save weight.

As Andy said, unless you tell us what size /kind of boat amd where/how used we really can't answer your question. And please register so we know you actually get our answers, otherwise it feels like we are wasting our time trying to help you.

Boat: 21' sail, 2000lbs disp. (rigged dry) 1/2 load with 340 lbs of batteries 3000 lbs) Hull speed 5.5 kts or 6mph. Motor(s) Torqeedo Cruise 2 ( 24v ) similar in power to Johnson 4 (Twin cyl, 2 stroke)or Honda 5 (single cyl, 4 stroke) Top speed Johnson 5.7kts; Honda & Torqeedo 5.6kts For Static torque/thrust and acceleration the Torqeedo proved dominant. Test range on Torqeedo was 80 minutes or greater per 75 Amp/12 AGM battery @ 4kts 24v (2x 75a/12v "sonic" AGMs in series- 55lbs each or 110 lbs) 160 minutes/ 2hr 40min 24V 4x 75a/12v AGMs 6 hours @ 4 knots = 24 NM. The same battery pack, rested 2 hours gave us another 2 hrs at 2 knots in reserve + 1 hr@ 2knot= 30mi- 2nd bank). Precision 21, keel/cb fractional sloop, driven by Torqeedo Cruise 2 'tiller' with 6 G-24 AGM battery system (Bank #2: 24v 2x G-24 150 Amp + 300 Amp 4x G-24 Bank) Drove the boat to Hull Speed Had power to drive into wind/waves and cruise at 4kn+ Range (by actual test- 1 ft waves- wind under 8 knots no sails up) 40 miles @ 4 kts DRjones360- Bellingham WA Google Sailing Avalon, YouTube The greatest thing... quote by Gurta below was taken by Adm S. E. Morrison

not sure I found the right you tube clip. Saw a red white sailboat with solar panels but no sign of a Torqueedo motor. and it had sails up. Lots of hits searching for "the greatest thing" such as "http://www.youtube.com/results?search_query=the+greatest+thing+ever&search_typ

evidently this is a very popular phrase to accompany You tube video clips.

Hello, You could check out this site http://www.ecyclemarine.com/eCycleAuxliaryPowerUnits.html

Many hybrid systems in the marine field... its all about the battery bank and the charging....

Odyssey Batteries ...and the BIGGEST battery charger you can afford...

algorythm for charging the Odyssey's must be correct as well

How big is your budget? You may be able to find used golf carts with 48 volt motors and controllers inexpensively. Good luck.

Larry, my limited experience with a (full size) boat is, a boat is a hole in the water that you pour money into until the lake fills up... The two happiest days of boat ownership for me: The day I purchased, and the day I got rid of her! I am assuming this is a R/C Model boat? If yes, it will simply be a smaller hole in the water, you will have to cram the money in.

There are a few posts cautioning high expense. So? Is that unexpected? Model boats, planes, cars, rockets, trains are a TON of fun, and there are many less enjoyable ways to rid yourself of extra cash.

I have nothing useful about your question, others have given you several leads. Have fun, my friend.

Doorman; by high expenses we means extraordinarily higher than boat construction in general. In most cases the eletric propulsion package alone is large enough to equal the purchase of aa complete boat with conventional propulsion.

Some of the hybrid systems I have looked at for my own design work cost a quarter of a million dollars to which you now have to add the cost of the rest of the boat which can easily amount to another half a million dollars .

Sadly many people turn to electric propulsion thinking it to be less expensive or ecologically more beign (green) when they do not understand the whole process.

Purely electric boats that recharge from the power grid simply shif the pollutin source away to a distant locale. Depending on what and where that power generation facility is this may be just as polluting as having an internal cmbustion motor on the boat. The only difference being where this pollution takes place. I get potential client asking abot hybrid propulsion for ocean passage making boats. This is probably the least practical application. These people assume that because cruise ships are diesel-electric it must be better than direct drive diesel. Not so! They do not pay attention to how a cruise ship is used .

Go to the 'Electric Boat Association' - they have done a lot of work on this.

READ EVERY WORD of www.mogcanalboat.com then; 1.Boat design, type, use, sea state etc. 2.Cost to create. 3.Cost to run. 4.THEN horse power and fuel, prop type, size etc. 5. KISS, keep it simple smarty! Keep us informed too.

MOG I see from your website you ended up using an ecycle generator. Are you completely satisfied with its performance? A couple of years ago I contacted them but found they could not promise acceptable battery charging characteristics. Instead we ended up getting a custom build generator and saving about $1000 or so in the process.

I see auxilary power units on comersial aircraft that are turbine powered. Because airlines are always looking to save wieght whenever they can I assume they are very efficient. Would they have any value as a battery charging system on your boats?

The problem with turbines in boats has always been the high air flow needed to keep them happy. Past experiments proved unsucessful due to igestion of salt laden air. turbines did not last very long.expensive to refit.

That is what I get for trying to think. Thanks.

Don't feel bad, the turbine powered boats were built and tested by big name manufacturers, most of them were sport fishing boats where high power and fast running speed were more important than expense. At this time the only continued use of turbines afloat seem to be hover craft and military hydrofoil. The hovercraft has these giant air scoops on deck and looks ugly but functional. A few mega-yachts also used turbines but it take a lot of deck space to accommodate the turbines inlet air scoops. Not practical on mid sized boats. I did see a PT6 helicopter turbine used in runabout some 10 years ago but it never caught on. The whine was quite objectionable on a small boat.

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These APU turbines are small. The exhaust pipe is only about 3" . I will try try to get a closer look at one to get voltages amps and sizes.

But what about inlet air duct size and how do you keep spray out of the inlet?Igesting salt spray is by all accounts detrimental to turbine engines. The traditinal method of using a labyrinth pathway imposes air flow restrictions that are unacceptable for turbines.

Second issue is the fact you really only need 4 or 6 kilowatts of charging energy. Most turbines are bigger than that. There is a company that builds microturbines but even their smallest model is almost too big and cost way too much compared to other power generating sources. Not to mention which these gulp way too much fuel. We should be thinking of how to need less power not find wasteful ways to generate more power. I'm looking for 1- 4 kW.generators, not 10 - 20 kW charging plants.

The controller which would make the system work best is the new Navitas Technologies unit. I believe, not until about July of 2009, has this unit been tested and become a controller for market release. I use the eCycle motors as generator and primary power units with Navitas controllers. These systems are currently under configuration and testing. So far they are robust and work exceptionally well. More on the systems as testing draws to a close, in the February 2010 time frame. MOG Canal Boat is a single solar electric concept yacht, not for sale and privately financed. www.mogcanalboat.com

Pure electric boats which do not have charging capacity on board are relying on charging facilites ashore. Many of these utility generators are considered significant sources of pollution.

Pure solar charging has not proven itself capable of providing sufficient charge rate except in near tropical latitudes. Sydney harbor in Australia has a solar powered power catemaran ferry that is almost self sufficcient. More recently Island packet build a design by Reuben Trane ( I think) which turned out to be disappointing in terms of speed achieved. Canal runners like the MOG boat may deliver closer to expectations even at higher latitudes such as SC. however I seriously doubt the insolation available above lat 45 is going to be sufficient . The typical sized pleasure craft simply does not have sufficient deck or cabin top area to carry enough solar panels to be self sufficient. In order to be practical and have sufficient buyer appeal electric propulsion boats will need to be either hybrid or else shift the pollution point to somebody elses backyard by plugging into the utility grid.

Andy has the right idea. Modern developments in steam power is likely to be more ecologically friendly and carbon neutral than internal combustion engines and more cost effective than solar /electric.

HOOKED an eCycle motor/generator to a lightweight, liquid cooled, Kawasaki V twin and could easily pump out over 6 Kw through a Navitas buck/boost controller. eCycle might be making their own controller soon, you would have to call. The whole unit weighed 125 pounds and extremely quiet. The motor/generator also started the engine. The original plan called for two eCycle motor/gens at about 147 pounds and nearly 14 Kw. Way more than I needed and Way cool. Sorry about getting back to you so late. Any further Qs, let me know.

You have been made fully aware of the multitude of variables. I am an electric boat enthusiast (designer) myself, my motors of choice are in the $50k zone, before supplying power! I will endeavour to lead you, to a few interesting sites though, where motor assemblies can be had in the $2500 to $4500 range, ie: being a 96 volt 50 hp AC motor, c/w controller assembly, that would power 40' trawler with full displacement hull @ 6 knots all day long if you had enough storage capacity for 6 volt batteries in banks of 16 ea. ( a multiple banks would be required) or a combination of hybrid tech. using smart charging system with diesel inverter generator or solar or wind generation for that matter. In any case a smart charging system is required! There are many sites worth visiting and many offer less expensive options then that which I mentioned! Try these: www.evparts.com, or www.u-fabboats.com , they sell an electrical motor system that works well, also search for E-Tek Motors, or even Briggs & Stratton they sell an E-Tek outboard motor...let me know how you did, and lots of luck with your project....

Doorman, in today's terminology electric boat implies a boat you ride in not a model boat you control remotely. Electric propulsion has many advantages. Despite military applications for submarines going back a century, the use of electric propulsion for recreational boats is still in its infancy.

The mention of 10 HP is a clue to boat size. For displacement speeds such a sized electric motor will easily propel a 35 foot boat. It is far too much power for all but the very large model boats. A naval architect colleague of mine is currently building a scale model of one of his designs that require 5 HP for a 60 inch long model and that boat model will reach scale speeds of 70 MPH.

Hey ! Larry where are you? ARe you reading any of this .

i have a new 15 hp dc motor and adj drive contact me @ masseycrane @gmail.com

I looked at building a diesel electric narrowboat about 15 years ago - but not by spending thousands on it. 10 hp was a bit big (bearing in mind that 1 hp was equal to one horse that pulled a boat with power to spare)

I looked at milk-float motors for cheapness - you could pick one up for about £20 at a scrap dealer.

All my problems however translated into the means of voltage conversion, forward/reverse speed control and battery charging - and that is where I got bogged down because composite controllers did not exist as such.

In the end I didn't bother - but things have moved on since then.

Good luck.

First and electric motor has about 1.5 times the torque as a gas motor so will need to match it to the lower unit. This company has both motors and controls http://www.fsip.biz/

I would recommend a Curtis controller its encapsulated and easy to use. You may be able to acquire one of these from an material handling service company. As most of the electric pallet trucks use them. Most of the motors used are from golf carts may pick one up used and inexpensive from golf course or repair shop for golf carts. Most are about 7.5 hp and run on 24 vdc. They remove the gas engine from the lower unit of an outboard fabricate an adapter to stand the electric motor away from the lower unit. Then use Lovejoy coupling to connect electric motor output shaft to the lower units in put shaft. For power cables use welding cable easy to flex and to route thru the boat.

I would not use welding cable in boat wiring. The cable is not suited to marine use and is considered expendable in use. Welding cable often develop cracks which in welding applicatinon is not critical but can be quite destructive in boats. Stray current leakage current can do such extensive corrosion it literally causes boats to sink.

The use of welding cable is to the fact that they will need to be changed due to the corrosive nature of lead acid batteries. The off gassing of the cells tend attack the copper conductor of any type cable you would use. If we are worried about stray leakage currents then why place a battery on board at all. They all tend to have a small amount of leakage current. I have seen welding cable used on many of bass boats with none of the effects that you describe let alone sinking one.

WI have seen welding cable used on many of bass boats :

Not to be disparaging towards that class of small boat, but the ABYC standards specifically rules out use of welding cable for good reason. Bas boats are often trailered and thus stored out of the water much of the time. Real boats that are in the water 24/7 are subject to very different stresses. Not the least of which is salt water. I earned my living doing repairs to boat and saw first hand how destructive stray current corrosion can be in salt water. when I worked in the Great lakes ( fresh water ) we never saw such damage. If Bass boats is your only experience base, you still have a lot to see and learn about marine wiring problems.

Concerning your comment about corrosion of battery cables, That is only true if proper installation practice is not observed. Marine grade cables and proper heat sealed heat shrink will resist battery acid fumes for many years. Marine grade wiring is specifically formulated to resist attack by oil, acids and is rated for higher temps.

Based on your comments I suspect you have only seen poor examples of wiring done by people who were not taught the proper way to do marine wiring.

It has been my observation that bass boats and such are often wired using automotive grade wire and brass plated fittings not true marine grade equipment. Automotive wire is SAE grade and not adequate for marine service. It is cheap crap by comparison. The ABYC standards has 76 pages just on marine wiring practice and that does not include the UL standards for what it takes to qualify as marine grade.

Welding cable is essentially disposable cable. Its primary characteristic is flexibility and the rubber like insulation does not have the requiste characteristics needed for permanent wiring installations.

In you vast experience what size real boat would you say a 10 hp electric motor would power?

A 10 HP electric motor would propel a displacement hull of 35 -40 foot LOA. As I metioned in a previous post some speed boats using a 25 HP electric motor have be built. These boats plane and can pull a wake board. But energy consumption is considerable and wasteful. Battery capacity does not last long.

One of the productiion boat companies is near Lake Geneva and one is near Seattle Duffy boats are strictly displacement and Solomon technologies has a 7 HP high tech motor that they recommend for boats up to around 35 - 40 feet. Larger boats have been fitted with two such motors on a common shaft. The draw back for small boats being Solomon Technologies motors require 120V DC thus needing 10 X 12V batteries wired in series. Even if you used garden tractor sized batteries this is a large volume of battery not to mention weight. Internal combustion motors typically have a reduction gear in the drive line wheras many electric propulsion motors are direct drive with no gearing to slow the prop shaft down. Eletric motors hve far better torque at low RP.

This has been a very interesting discussion and I've learned a lot from it.

I though it would be worthwhile at this point to talk about something that has been mentioned but might have gotten lost in the discussion details. That is the issue of just how much power is needed in a given application. There are reasonably decent references on power required to reach theoretical hull speed instill water. And one of the primary reasons for construction an electric boat is to provide a quiet cruising experience in quiet sheltered waters.

But there are many parts of the world where navigable waters are delightfully calm in the morning and evenings and rough as a cob when the wind blows up in the afternoon or in the face of approaching weather. If the course to be followed is a beat to windward additional power will be required an the worse the conditions the more power will be needed to make headway.

So the question I pose here is what are good rules of thumb for the amount of excess power needed in reserve for various boat types and sizes above that needed to reach hull speed? What effect does streamlining of the above water parts of a boat like deckhouses or windshields have? Can you folks here that are experienced in this sort of thing recommend specific references or web links that discuss this issue in some detail?

Ed Weldon

Ed; experienced designers estimate a 25% to 50% overage above the theoretical is suficient to handle normal wind resistance loads. This obvious varies depending on superstructure design. For example George Beuhler designed a 55 foot boat called Idlewild (website blog available ) that was powered by a 75 HP kubota diesel. That boat cruised round the world in 14 months while encountering rough seas and plenty of normal wind storms along the way. No problem due to being underpowered.

Conventional thinking in the US puts about 300 HP into such a size boat. Way too much power. but that us due to marketing.

Skeene's element of yacht design (out of print but available thru amazon used books)has tables and curves for deriving theoretical horspower for a given hull size and weight. Dave Gerr published a book on propeller design which also helps determine horse power. These are among the best reference text for home builders. Dave Gerr is the Director of westlawn school of naval architecture. As such he is an emminent authority to consult.

enlav and others, your comments have been most interesting. Having designed and built and currently invested in a number of products I have used, I feel my nearly 24 years on this project might help point, all concerned, toward the practicalities and non-practicalities of solar yachting. I will be updating the site www.mogcanalboat.com in April (when we endeavor to do the loop). Both of the 10hp eCycle outboards are tested, working well and should be on the ALGEMAC II this month. If you read all the info posted on the site (including some of the links) you could get a better appreciation of what is really involved. The site is not polished, just design at the speed of life.

Please keep us updated via this thread when you get going in April and later on. I have kept this thread active as one I continue to follow. It started two years ago but continue to be of interest.

As a sailor from an early age till I was about 35 (children stopped that!), I can say that although I am mostly against noisy smelly motors on sailing boats whenever possible, if you get into a jam and need either to get out of a tough spot, or even just stay where you are for a moment or two, its nice to have a motor.....

....but it should never be something you NEED every day. Sailing should be learnt properly and fully to allow you to pick up a mooring, sail alongside, back into a parallel parking spot, pick up a dropped hat/fender/person etc etc without switching it on...

.....as of course a motor can fail, you run out of fuel (or simply did not take enough! The two are actually quite different as I once found out!).

I do not see any difference with using an electric motor, except that refuelling may be an even greater problem unless you have an onboard charger and shore power.......I hope to be wrong on this point and that you can recharge on a sail, but I am very sceptical........

Also the simple weight of the number of batteries needed to give you say 2 hours of motor at full power will be more than if you actually took far less batteries and say a lightweight 10 HP diesel motor turning a matched alternator set up as a charger. In the car industry you would call it a hybrid.....possibly the best of both worlds.

So to sum up, do learn to sail properly and hope that you will never need the motor, BUT that the batteries are always fully charged when you do.....the sea is unforgiving of errors.....as many have learnt to their cost!

Best of luck.

Larry, happy to start a discussion with these two 10hp converted Mercury 9.9's. Please consider the fact that 10hp is quite a bit of power when correctly applied to a displacement hull of 8ft beam and 32 foot length at the water line. You tube has a clip recently shot. MOGvideo1.mov can be typed in at the site or at youtube http://www.youtube.com/results?search_query=MOGvideo1&oq=MOGvideo1&aq=f&aqi=&aql=&gs_sm=12&gs_upl=5054l13483l0l18816l9l9l0l4l0l0l490l1534l0.2.0.2.1l5l0 The MOG site is not fully functional and will be totally up and running in April 2012.