[MedSailor]

I've been thinking for a long time about adding an auxiliary electric motor, and with my new boat, I might just do it.

The PRIMARY purpose would be to silently add a couple of HP while under sail to make motor-sailing a pleasant and efficient process.

Secondary functions would include using the high torque of the electric motor in close quarters maneuvering and possibly as a get-you-home backup.

With my new boat (Nauticat 40) I have copious battery capacity, and space for more, and I have a 6kw diesel genset. 6kw happens to be about 8HP, which if you follow the formula of 0.5hp/tonne to get to 80% of hull speed, means that in theory an electric motor coupled to my 6kw genset could push me at 80% of hull speed. But that's not the primary purpose. Really what I want is to silently add a few HP under sail, and as far as getting me home, I could sail (or electric/motorsail) to the marina and use the electric motor in close for docking.

Here's what I'm imagining for how to connect it. I could use a high grip shaft collar, coupled to a sprocket and motorcycle chain. The use of roller chain (motorcycle chain) would eliminate the side loads that trash out bearings.

McMaster-Carr

The sprocket could be attached to the coupler with very little imagination I would think.

What I would need is some kind of clutch (electromagnetic?) so I could engage or disengage the setup when running the main engine. I also haven't figured out the best motor to use, though there are coutless options out there.

Does anyone have an idea what kind of clutch I could use to attach this sprocket setup to an electric motor? Any ideas on hooking it up to some kind of throttle (resistor?) Any other comments or criticisms?

MedSailor

 

[Capt Len]

You could drive the shaft with 3 B series V belts and an idler to tighten. The belts would be slipped on the shaft before coupling and rigged to not ride on the sheaves when slack. This is how we used to rig alternators and emergency pumps

 

[kd3pc]

Read nigel calder on electric motors for boats, there is a lot more to it than you would think, especially what you are calling a throttle, a lot more than a resistor. Then there are the batteries to run the motor and anchoring it, etc.

Deep pockets will help as well.

YMMV

 

[Minnewaska]

I suppose it depends on how loud your diesel is and how often you expect to motor sail. On your hull, motor sailing may be more frequent than most.

However, getting OCD on sound insulation may be a lot less expensive. It doesn't seem like this a green initiative, since you'll charge from the genset anyway.

I hate to say this, because I don't wish it on anyone. However, after you settle in with your new boat, you are pretty likely to find all sorts of stuff that requires your money and attention that is already there. I wouldn't dive head first into optional surgery for a bit.

 

[knuterikt]

Steyr motors have already developed a hybrid system for boats

Why don't you just order one of those
Full Hybrid Propulsion System - Diesel and Electric - Steyr Motors

 

[kd3pc]

Steyr motors have already developed a hybrid system for boats

Why don't you just order one of those
Full Hybrid Propulsion System - Diesel and Electric - Steyr Motors

I believe this is one that Nigel Calder has been evaluating/working on for the past year to two.

It appears to be one of the best out there, right now, for sail boats. Steyr has a long, sterling reputation, going back decades. While it is about the best out there, it is not without it's challenges as described by Calder. Especially where cost or refitment is concerned. I believe Calder says that for most of us, the conventional diesel auxiliary is still the most reliable, economical and environmentally sound way to go.

He has been meticulous in accounting and measuring this system.

Deep pockets are still required, though, and long term reliability can not be examined until it has been in service longer.

 

[MedSailor]

Wait! Wait! No! I'm not going all out with electric/hybrid dives! I've done lots and lots of reading on all that and am not going there. What I want to do is install a true auxiliary electric motor that could add a couple of HP quietly while under sail.

I plan to leave all the running gear exactly where it is.

What I am planning should be small in footprint and expense and should use mostly components that are already aboard. The motor itself (used forklift motors can be had cheap) and the control unit and the connection to the shaft will be added but I'm thinking it may be possible to add all these parts for less than, or near the cost of a new Max Prop (the boat has a standard 3 blade 22-inch prop).

Capt Len, thanks for the connection suggestion. Certainly a simple solution, but removing all the floorboards and soundproofing and crawling around in the bilge before starting the motor doesn't sound like fun. I'd like the setup to be easy to use.

Minnewaska, Thanks for the out of the box reply. Actually, the Ford Lehman is MUCH quieter than the perkins on my previous boat. The perkins was so loud that I pretty much never spent any time below while it was running. My new engine is slower turning and the floorboard soundproofing is much better. Currently, it's not unpleasant at all to be below with it running. What's more, is that the nauticat yard installed a second layer of soundproofing (with lead and foam) around the engine compartment that is currently aboard but not in use. I can't wait to see how quiet she is with all that installed. What's MORE is that there is a THIRD layer of soundproofing (an enclosed soundproof box) around the genset, so that puppy ought to be really quiet. I definitely should see if the engine is not unpleasant to run while motor sailling. That might just be the solution right there, with or without any more soundproofing.

Part of why I want to add electric is just because I WANT to add electric and play around with it. You're right though about many other things presenting themselves that will require my fiscal attention, but this electric drive system is going to require a lot of research and will be fun to think about and design in the mean time.

Back to clutches and drives. What about something like the clutches on engine powered watermakers and refrigeration? Could that be used with my chain and sprocket setup?


MedSailor

 

[christian.hess]

med I started a couple of threads way back when I was looking for an inboard replacement
for my islander 36.

my issue was parts availabilty and equipment

if I was in the states I could of made it happen

in your case I would look for golf cart motors that are generally 24-48 volts, most commonly 36v...they are anywhere from 3kw to 10kw in size and power

rigging them up on your current shaft by way of pulleys and or chain drive is easy.

look up

electricmotorsport.com for parts and hardware

then get some 4 batteries...you can have a freewheeling hub type scenario without getting an expensve clutch tranny system and then engage when you want to charge up some extra juice or for when in silent mode using eletric power

my issue down here was I couldnt even get a motor to start with...

I would recomend going all dc for simplicity...

my cents

christian

BTW I reseacrhed for mooooooooooooooooooonths and came up with some very nice alternatives...but money got tight and shipping heavy stuff down here is too expensive

 

[HUGOSALT]

Wait! Wait! No! I'm not going all out with electric/hybrid dives! I've done lots and lots of reading on all that and am not going there. What I want to do is install a true auxiliary electric motor that could add a couple of HP quietly while under sail.
MedSailor

Would not involve clutches and gears...but if you are flush with electric
and only want to add a couple of hp while sailing...explore a trolling motor,
Minn Kota salt water series...can mount perm or removable and lower prop to
water in an instant. Comes in 12, 24, or 36 volts ...and very quiet.
Thinking even come with a remote. Very smart looking white motor with
carbon shaft and can use as aux. for dinghy exploring back bays or fishing.

 

[christian.hess]

on a 40ft motorsailor?

 

[HUGOSALT]

Don't know, but used as intended by MedSailor..a 160 lb. thrust with the right prop
could deliver the desired 2 h.p. ...depending on who's formula/math you use.
Seems motorsailing at rather low rpms (thrust), provides a synergy beyond
the math.
Maybe worth a look at website if nothing else.

 

[MedSailor]

HugoSalt

While I doubt a trolling motor would do me much good, I really DO appreciate the suggestion. I just procured a large sized Torqueedo outboard, and your idea gave me the idea that I should try stern mounting the Torqueedo and see what it does. It's quite a bit more thrust than a trolling motor, and would be easy to implement. Even if it doesn't do what I desire, I could use the thrust specs to help guesstimate how big of an internal electric motor setup I will need.

MedSailor

 

[hellosailor]

Chains and sprockets are inherently noisy. This is why so many cars went to "rubber" timing belts instead of metal timing chains.

And who needs a clutch? When you are not driving the electric motor, isn't it a DC generator that can be left attached, charging your batteries, heating your water, doing other useful work?

 

[MedSailor]

Chains and sprockets are inherently noisy. This is why so many cars went to "rubber" timing belts instead of metal timing chains.

And who needs a clutch? When you are not driving the electric motor, isn't it a DC generator that can be left attached, charging your batteries, heating your water, doing other useful work?

An interesting thought about chain noise. I can't imagine it would be that bad... I once went to an electric boat talk and the guy giving the presentation said his company used supercharger belts. Said they were immensely strong. I could use those, I suppose but the parts seem less easily available.

I could leave it attached, but then I'd need to make sure it was adequately cooled, could handle the max RPM of the motor for long periods and would have to regulate the charging current. I'm sure my 90HP engine has a few extra HP to give up, so the draw on the engine shouldn't be a problem. Not impossible to set up this way at all, but simple is part of what I'm after.

MedSailor

 

[christian.hess]

simple is slap on a dc motor on the shaft with sprockets to use as an alternator....since its dc volts go back in when you want to use it as a silent dc motor...all electric.

chain and sprockets make no more noise than the mosy silent diesel engine...so that nonsense doesnt pan out....

lube...clean and do like you would a bike chain

 

[Capt Len]

Problem with chain drive is it's on all the time unless you've got a clutch on the shaft itself. Possible but I've never seen a suitable critter. One could make something up using the syncro slider like a dog clutch from a truck trannie but that gets more complicated.The belt drive doesn't touch the shaft when slack and idler operated by a lever, wedge or remotely turned screw .When the shaft is electrically engaged the transmission is turning (oil cooling etc)so this is not a stand alone gizmo for long. Also the side pull of the belts on the shaft is considerable and can bend a toy . I put on a Maxi and never looked back.

 

[MedSailor]

Why is chain on all the time? The way I'm picturing this it's no different than belts but eliminates the side loading issue. What about watermaker and engine refrigerator clutches? Couldn't I use whatever they use but with chain?

Btw what do you mean by "I put on a maxi". I can only think of one meaning for that and I'm quite sure it isn't what you meant.

 

[P35juniper]

Instead of chain use a cog belt sometimes called timing belts, as to clutches, just let it spin, unless you have a huge gear reduction there will be little drag,
Best would be if you could find a double shaft motor that runs the same speed, rpm, as the shaft, and you have the clearance from gearbox to seal to fit it. think WarP motor.
I'd like to do this mostly to power on/off dock, mooring, for 2-5 minutes without starting the diesel, and could also use it as a big alternator

 

[P35juniper]

Len ment Max-Prop

 

[Capt Len]

D3, Depends on your needs but that makes me feel better