Diesel Electric Drive System Engines and Such Forums

I moved your post over to the engines forums 🙂

sigh... an electric motor system is to me the holy grail 🙂 I would love to be electric or diesel electric. The bottom line though is for a boat our size and weight it is really cost prohibitive and hard energy density wise to put in an electric motor and power supply (ie battery bank) big enough to give enough power for a reasonable duration. Boats in the 30 ft range and under are now doing this both semi economically and with reasonable power levels. Jumping from a 6 to 9 thousand lb boat to a 20,000 lb boat creates a lot of problems scaling the power up.

Options are

• straight up electric with a battery bank to power it. Disadvantages are how to charge it and power density. You can get an hour to 4 or 5 hours of motoring out of this system depending on if you go with low density but much cheaper lead acid batteries or with Lithium batteries. Charging needs a shore charger or generator. Large solar array would work but probably take a couple days to fully charge in ideal conditions.
• Diesel Electric is the most usable solution... for our boats though you would need a 12 to 20 kilowatt generator and a massive 30 to 40 hp continues duty electric motor plus all the attendant controllers and such. You could run off smaller battery bank for moving around the harbor  and use the diesel generator for longer distance motoring. In effect you will have to put in the diesel engine and the electric system. This should give you a little better fuel economy over the long run I think but I doubt you would recoup the initial investment over just having a setup like we have now.
• Auxilary electric.. I think this is the most practical alternative. You have your currant engine and setup and add a smaller 10 hp or so motor on a clutch that can turn the existing shaft and prop when the engine is in neutral. A reasonable battery bank and you can cruise for hours a half of hull speed and maneuver around the harbor all day long under electric but for hull speed long distance you can use your engine. You might also be able to run the electric motor as a powerful generator to charge the battery bank while motoring.
• true auxiliary electric. You have a big battery bank and and smaller electric motor able to push you 3 knots or so for close in and harbor maneuvering and to give you a little push when sailing in light air. Otherwise you sail like you have no engine at all. 🙂

so the elco system.. looking at the ep-2000 which would be the motor I would choose. Your cost for straight electric would push 18 grand or so between motor, controllers, chargers and batteries..  Adding the hybrid option would bump you to about 30 grand. [Image Can Not Be Found] however based on their numbers, and I think they are probably realistic on our hull, with our 90 gallon fuel tank you would have a range under power of about 1500 nm at around 5 knots. 🙂 my estimates of cost don't include installation unless their pricing on the website already includes that which I think is not likely[Image Can Not Be Found]

If your handy and put together your own system you could probably do close to the same system pieced together for about 13 to 15 grand for electric motor, batteries and generator. Still pretty damn pricey.

I would love to see it done though, so we are all waiting on you to do it first and let us know how well it works [Image Can Not Be Found]

They play with numbers... those generators will not be able to run the electric motor at full throttle

20hp electric is what..... 14,800 watts so no it won't push you to hull speed on a 4000 watt generator. However it might get you to 5 knots. Or maybe to close to hull speed in flat water with no headwind. Our boats are real easy to push through the water. If you ever notice under power how little wake we create, this shows how little resistance through the water our hull form is giving us.

Of course that 20 hp number they are throwing out isn't the actually output of their motor. Actually their motor is putting out less than that. That number is their equivalency number to a diesel engine hp. The big difference is torque.. We normally never run our motors wide open, max rpm.. which is where our hp rating comes from. We can create a lot of torque with a electric motor at much lower actual HP which allows us to swing a bigger prop which increases efficiency greatly.

I could probably explain it a bit better than that, as this is a rough analogy, but my brain is hurting and I just don't feel like being that intelligent right this moment 🙂 lol.  I swear once in a while... well every decade or so... I might rise to feeling smart 🙂

as to the prices.. I just used there prices on the site and then added 30% for labor. You definitely could do it for much cheaper. Actually look at http://www.electricyacht.com .. I think they are pretty comparable.. hmm pricing for same size unit is about the same. Their smaller kits up to 12000 lbs displacement are under 3000 for the motor kit. They have a kit for 5 grand range to add an 8 kilowatt system to your existing motor between the transmission and the prop shaft. They say it only needs 4 inches of clearance between the tranny and the stuffing box.

hmm.. yeah that doesn't sound good... engine itself doesn't sound bad.. maybe adjust the valves.. They sound a little lose but that rattling/clang isn't good.. maybe something just needs to be serviced in it.? I don't know a lot about transmissions other than the general idea of what they do though. I also know I would want to find someone really reputable to look at it as lots of mechanics will just tell you "oh you need to replace it" when it could just be a simple adjustment.

Hopefully someone else here will know.. other than that you might try one of the boat forums that are focused on engines and transmissions.. I think one is iboat? I know when looking for parts for outboards and my universal that I have run across them a few times and people were answering questions there. If you hear something on one of them let us know here 🙂

I don't think you can get the shaft on our boats out to the rear without removing the rudder. Easiest way to do it would actually be to pull the engine up and pull the shaft forward and out. Mine would only move 8 or 9 inches before it hits the rudder. Actually there is only and exactly enough space between it and the rudder to get the prop between them to get it on and off the shaft.