Ideal Generator?

[DotDun]

Originally Posted by SVI

Exactly. And a 570A 24v is built to mil specs, installed on a Humvee. They made a lot of them - hence mil surplus now.
Weights 51kg though. Still lighter than additional gen. And ca $500 on Ebay new.

With Lifepo4 batteries, the gen running principle became different - run your DC gen flexibly and with 100% load to charge batteries, and everything else from inverter.
If the bank is big enough - charge it when you motor.

I don't know why I'm hung up on this ........ please correct my thinking.

Hanging a load off the side of a sailboat engine driving a belt that pulls 20hp (570A * 24 = 13,680w / 700w/hp) is not a good thing for the main crank bearings!! ??

Are there any engines with the specs to handle this side load? My belief is that most of these engines are built for loading in-line with the crankshaft.

[Southern Star]

Some years ago I owned a Bayfield 32 with a Farymann diesel and hydraulic drive and, while the drive eventually developed some leaks, it worked incredibly well:
1. It allowed you to keep the diesel at constant revs while approaching a dock and 'feather' the thrust by adjusting the drive engagement; it also allows you to rapidly switch from forward to reverse and back without changing gears or reducing revs (there is a valve which reverses flow direction to the drive unit). No clunking gears!
2. They can be easily tuned in order to reduce slip by engaging drive and adjusting the internal plate positions/angles. Sorry, I forget the proper terminology, but in any event the adjustment was by means of an external fitting - no disassembly required. Just as with hydraulic automatic transmissions in a car, there will always be some slip, but it need not be anywhere near what the earlier post observed on a tourist cat with hydraulic drive.
3. The pumps on my boat had been designed for use with lawn tractors and were neither expensive, nor heavy. While they eventually (after 10 years) developed a slow leak, my hydraulic mechanic (who had worked for years as a hydraulic mechanic in the commercial shipping industry) stressed that leaks are not endemic to hydraulic pumps. At a certain point they will require rebuilding/replacement, but in proper working order they should not leak.
4. As has been pointed out, they permit shaft drive with virtually unlimited choice of location for the diesel. This is, of course, better for both access and weight distribution. Indeed, I recall some S/S IOR designs from the 70's that placed the diesel amidship, under a cover which doubled as a saloon table.

I have always believed that the advent of sail drives by marine diesel manufacturers stopped the use/development of hydraulic drives as they were cheaper to install than shaft drives , while also permitting at least some freedom in terms of engine placement.

Brad

[Dockhead]

Originally Posted by DotDun

I don't know why I'm hung up on this ........ please correct my thinking.

Hanging a load off the side of a sailboat engine driving a belt that pulls 20hp (570A * 24 = 13,680w / 700w/hp) is not a good thing for the main crank bearings!! ??

Are there any engines with the specs to handle this side load? My belief is that most of these engines are built for loading in-line with the crankshaft.

That's the reason for the jackshaft mentioned in the first post.

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[Dockhead]

Originally Posted by a64pilot

Off topic a little, but why does a School bus need a big Alt? Ambulance, yes, even my pickup as it could charge the bank in my RV, but a School bus?

Good question. I don't know. But the same units are used for emergency vehicles, mobile command posts, military vehicles, etc.

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[DotDun]

Originally Posted by Dockhead

That's the reason for the jackshaft mentioned in the first post.

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But now you are talking about a dedicated DC genset, not driving an aux alternator off a propulsion engine.

Or are there transmissions with PTOs?

ISTM, the goal of simplicity gets diminished greatly when things like jackshaft, PTO, custom mounts, etc. start entering the picture. I lean towards simplicity equaling a tried and true solution with all the kinks worked out by someone else, like the Northern-Lights-throw-it-away-every-10,000-hours model.

[Dockhead]

Originally Posted by DotDun

But now you are talking about a dedicated DC genset, not driving an aux alternator off a propulsion engine.

Or are there transmissions with PTOs?

ISTM, the goal of simplicity gets diminished greatly when things like jackshaft, PTO, custom mounts, etc. start entering the picture. I lean towards simplicity equaling a tried and true solution with all the kinks worked out by someone else, like the Northern-Lights-throw-it-away-every-10,000-hours model.

Read the first post! Yes, dedicated generator.

But one school bus alternator on the main engine is also great. Lots of us have them. If it's not a monster like those Iraq surplus ones, but more like my present 2.5kW one, the side loads are no problem.

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[DotDun]

Originally Posted by Dockhead

Read the first post! Yes, dedicated generator.

But one school bus alternator on the main engine is also great. Lots of us have them. If it's not a monster like those Iraq surplus ones, but more like my present 2.5kW one, the side loads are no problem.

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An example of a Yanmar recommendation for the jh4..

Marine high output alternator and second alternator discussion

look at the engine mounting configuration section.

[Dockhead]

Originally Posted by DotDun

An example of a Yanmar recommendation for the jh4..

Marine high output alternator and second alternator discussion

look at the engine mounting configuration section.

I guess the 4JH4 must have a lighter front crank bearing. My 110 amp x 24v 2nd alternator was factory installed; standard equipment on all late Moody cruising yachts with 4JH2 and 4JH3 Yanmars. Never heard of a single problem.

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[carstenb]

Originally Posted by Dockhead

I guess the 4JH4 must have a lighter front crank bearing. My 110 amp x 24v 2nd alternator was factory installed; standard equipment on all late Moody cruising yachts with 4JH2 and 4JH3 Yanmars. Never heard of a single problem.

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I have a 4JH4 and wanted to upgrade.. Absolutely no way fit an extra generator in the way this is mounted in the pics as per Yanmar specs. Ended up going with a Mark Grasser 160 amp generator and serpentine blets.

One of the side benefits was that the old hitachi running on a single belt would slip under very high loads and throw rubber dust all over the engine compartment - a total mess to clean. (I've talked to several other Jeanneau owners with the 4JH4 and they have the same problem)

[Dockhead]

Originally Posted by carstenb

I have a 4JH4 and wanted to upgrade.. Absolutely no way fit an extra generator in the way this is mounted in the pics as per Yanmar specs. Ended up going with a Mark Grasser 160 amp generator and serpentine blets.

One of the side benefits was that the old hitachi running on a single belt would slip under very high loads and throw rubber dust all over the engine compartment - a total mess to clean. (I've talked to several other Jeanneau owners with the 4JH4 and they have the same problem)

Because it wouldn't fit?

Did you keep the old Hitachi such that the serpentine drives both, or did you get rid of it? Pics?

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[brianlara 3]

DOCKHEAD...why.. WHY would you NOT put in something like an ONAN or similar (but not Fisher Panda).???
Would you stuff around with a new MERC or BMW like this ??
FWIW, Ive trained and managed great Mercedes Benz mechanics.
K.I.S.S. KEEP IT SIMPLE. You are introducing a plethora of potential servicing/operational problems.
WHY IN GODS NAME would you just buy a top shelf genny, heaps of AH's and plug solid state things into it. ??

BL3

[Dockhead]

Originally Posted by brianlara 3

DOCKHEAD...why.. WHY would you NOT put in something like an ONAN or similar (but not Fisher Panda).???
Would you stuff around with a new MERC or BMW like this ??
FWIW, Ive trained and managed great Mercedes Benz mechanics.
K.I.S.S. KEEP IT SIMPLE. You are introducing a plethora of potential servicing/operational problems.
WHY IN GODS NAME would you just buy a top shelf genny, heaps of AH's and plug solid state things into it. ??

BL3

The answer is in the first post - simplicity and field-serviceability for adventure cruising in remote areas.

What I have now is a heavy duty low speed continuous-duty rated AC generator. A Kohler EFOZ6.5. It's an excellent solution and probably the right solution for most people. But if something breaks, you need parts and special tools and trained service techs.

The new boat is being set up for remote areas and high latitudes, and I want something simpler and capable of being serviced without special parts or tools.

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[brianlara 3]

A very unenthusiastic...ok !!
But I'm flattered that you even acknowleged my post.
Thanks "D"

[Dockhead]

Originally Posted by brianlara 3

A very unenthusiastic...ok !!
But I'm flattered that you even acknowleged my post.
Thanks "D"

Why flattered? You asked an important question.

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[carstenb]

Originally Posted by Dockhead

Because it wouldn't fit?

Did you keep the old Hitachi such that the serpentine drives both, or did you get rid of it? Pics?

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I dismounted the old hitachi (but kept it and all the flywheels etc in case the grasser ever goes down. The 80amp hitachi isn't big enough, but in an emergency......)

here's the front of the engine, hard to see, but mounting the Yanmar solution at the bottom left was a non-starter. The grasser solution also cost about half the yanmar

sorry this picture keeps coming up sideways - but if you twist you head you can see

EDIT-Way too pretty to leave sideways...