Push Start a Sailboat?

[SkiprJohn]

Back in the olden days everyone told me I couldn't start my Dad's old dynaflow '50 Buick by push starting. Wrong! Just had to get it going 15 to 20 and putting it in D.

It's always fun to try such things.

[markpierce]

Only times I've push-started a sailboat is to push the boat away from the dock and start sailing.

[roverhi]

Hand cranked a Volvo MD2B for ten years. The engine was easier to start when sailing with the engine in forward. Wasn't enough torque from the prop to turn the engine over by itself, but definitely easier to crank the faster the boat was moving.

The MD2 was designed to be hand crank started. It had a huge flywheel to store the energy that you built up by cranking. Open the compression releases, no way you were going to even turn it over without the compression released. Crank like crazy and then drop pne compression release when you reached your max cranking rpm. The flywheel would keep the engine turning for at least one complete evolution. That was enough to get the engine to fire on that one cylinder. Once the engine was firing on one, drop the compression release on the other and I was in business.

Even with compression releases on the 3GM30, doubt you'd have an easy time hand cranking the engine. They have a dinky flywheel that probably doesn't store enough energy to pull it through under compression.

[denverd0n]

Originally Posted by Sailmonkey

Nope, the transmissions are not designed to operate in this direction.

Transmissions and clutches in cars are not designed to operate in this direction either, but push starting is something that almost everyone who owns a manual transmission car has done at one time or another.

Not saying that push starting a boat would work. I'm guessing that it wouldn't. But I'm not buying the notion that the reason it won't work is because the transmission is not designed to operate in this direction.

[gonesail]

we had a yanmar 2GM that actually had a manual crank start mechanism but i never used it.

[Sailmonkey]

Originally Posted by denverd0n

Transmissions and clutches in cars are not designed to operate in this direction either, but push starting is something that almost everyone who owns a manual transmission car has done at one time or another.

Not saying that push starting a boat would work. I'm guessing that it wouldn't. But I'm not buying the notion that the reason it won't work is because the transmission is not designed to operate in this direction.

clutches in cars don't rely on the torque from the engine to squeeze the surfaces together. The reason manufacturers of marine gears say to not run with the shift lever ahead when sailing is for this very reason.

[denverd0n]

Originally Posted by Sailmonkey

clutches in cars don't rely on the torque from the engine to squeeze the surfaces together.

Hmmm. Good point. Automotive (and motorcycle) clutches use springs. I've never dug into a marine clutch, so I didn't realize they were that much different.

[Canibul]

These are 3HM-35's, if it makes any difference. there's one compression release linkage bar, which I think works all three cylinders by holding the exhaust valves open.

It will be easy enough to try if we go out for our planned overnight trip this coming weekend.

[S/V Alchemy]

Originally Posted by sailorchic34

You will never ever be able to push start a sailboat or any boat engine. You can't generate enough force on the prop to push start an engine.

Now some have used a rope run to the boom wrapped around the crank pully to start the engine under the right sailing conditions, but push starting is never going to happen.

This is the only way I have heard of this being done. Yves Parlier (if I recall) started his dead battery/engine in the Southern Ocean with a deliberate "crash boom/diesel pull cord" method when he beached his boat in the 1997 5-Oceans and cooked himself a new mast after he beached on some remote island south of New Zealand.

Now, that's a sailor!

[S/V Alchemy]

I would add that there is a non-electric solution that DOES work: a spring-powered starter. They are very common in Canada's North, where winter cold will kill an unheated battery (or where the gear is far from the depot). The spring, which is manually cranked, will get the flywheel spinning fast enough to start diesel compressions. I've considered trying to find a used one for my Kubota-based 2.5L diesel as an alternative to carrying a second starter on passagemaking. I discuss it in the context of "how much redundancy makes sense?" here:
The world encompassed: Make and mend: Spares, DIY and overthinking self-sufficiency

[Pete7]

Originally Posted by sailorchic34

You will never ever be able to push start a sailboat or any boat engine. You can't generate enough force on the prop to push start an engine.

Sorry have to disagree and this is the yacht, although not my photo. It was called British Soldier but had to be re-named Sabre when we started to interfere in countries we had no right to. Anyway on rough down wind trip from Weymouth to Portsmouth along the Jurassic Coast the engine repeatedly bumped started. I think they had a Perkins in them at the time with a 3 blade prop offset to Port. Needed about 10 knots so surfing down a wave would do it just nicely and when you least wanted extra speed.

Pete

[Canibul]

Originally Posted by SkiprJohn

Back in the olden days everyone told me I couldn't start my Dad's old dynaflow '50 Buick by push starting. Wrong! Just had to get it going 15 to 20 and putting it in D.

It's always fun to try such things.

I had forgotten it, but I definitely started a 56 ford with an auto tranny by rolling it down a hill one morning, after killing the battery by leaving the ignition on and the radio running all night.
Don't ask.

[a64pilot]

I'd bet you could get one with decompression levers going with the Milwaukee angle drill a lot of us use for winches

[a64pilot]

Originally Posted by Canibul

I had forgotten it, but I definitely started a 56 ford with an auto tranny by rolling it down a hill one morning, after killing the battery by leaving the ignition on and the radio running all night.
Don't ask.

Some of the old time auto trannies had a pump on the output shaft, those you could tow safely and push start, everything made since a long time ago has the pump on the input shaft and those you can't tow or push start.

[Panope]

I still have my first car - a 1965 Chevy with an automatic transmission. It "coast" starts fine from about 20 miles per hour. Needs a hill.

I wonder when this ability was built out of automobiles?

Steve