Bump starting

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LeonF

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Has anyone ever done this on a boat ?? Get the prop spinning while sailing then knock it into gear? I have heard of it being done, but wondered if it was just one of those tall tales.
 
Re: Jump starting

I think you mean bump starting don't you? The usual method is to get half a dozen strong blokes to leap into the oggin, making sure of course that they wear their life Jackets, they then proceed to push the boat as fast as they can, you then, when sufficient momentum is achieved, drop it into gear, and away you go.

/forums/images/graemlins/laugh.gif
 
Re: Jump starting

Yes you are right..have edited it. The way I heard it was to get her sailing as fast as possible. No use if the engine won't start in no wind of course..
 
Re: Jump starting

Given the amount of compression diesel engines have coupled with the inertia of their heavy flywheels, plus the fact that they are geared down to the prop, I doubt that it is possible to do this in most cases.
 
Re: Jump starting

The only instance of a related means of emergency start I have heard of was a Round the World - or some such - yachtsman who apparently wound a few turns of rope onto the flywheel and led it via blocks to the main boom, and then crash gybed.
This allegedly did the trick.

I should hate to have to try it, but fortunately my MD7A has a handle so hopefully I can use that, not tried it yet though.
 
i have some experience of this but it was in a fishing boat with an 8 cylinder engine with decompression levers on each cylinder which were fed in one at a time. the towing vessel was an equally powerful vessel.
not sure if it would work on a yacht tho.
 
Re: Jump starting

That did happen, saw the video. It was Michel Desjoyeaux in the 2000/2001 Vendee Globe.
 
In his book 'Blue Water', the late Bob Griffith records that he has done this on several occasions with a 30HP Yanmar. He describes the method thus:
'My Yanmar can be started by sailing the boat through the water at five knots or above. In neutral, with the decompression levers engaged, the thrust of the prop turning in the water turns the gears. I open the throttle, then I shift to forward to start the enging moving. As soon as it reaches a good speed, I put down the decompression levers and she fires right off'.

My Yanmar 3GM30F could be hand started, or so the workshop manual claimed, but I never succeeded. However, on several occasions I used the decompression capability to start it on a tiny residue of battery capacity when I'd been careless with power management.
 
I seem to recall...

that the late, and much missed, Geoff Pack (ex-editor of a sailing magazine by the name of 'Yachting Monthly') claimed to have achieved this on his Rival 34.
 
When deciding on props for my boat I was looking at Brunton Autoprops. The manufacturer advised against them as they could bump start the engines if left in gear at speeds above 15 knots. The same applies to Maxprops so I eventually went for folders. They do turn under sail but not enough to turn the engines over.
 
Some years ago while involved with the BSAC we had an incident report in from the Red Sea of an outboard starting when the prop was turned, with some damage to the individual. It was obviously switched on and in gear, it was put down to the fact that it was a hot climate and the engine was hot from recently being run.
 
i just use my engine handle and decompression lever, easy when you know how.

need a lie down after, just to get my strength back /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

leighb. you should try to start it on the handle, just incase you need to one day???
 
David Lewis in I think his first book described how one of his catamaran diesels inadvertently bump started in the Southern Ocean while surfing down a wave at I would imagine something like 20knots.
I understand you can do it with a jumbo jet but then that is not diesel.

If all diesel boat engines had hand start facility (that was doable) then it would save us a lot of anx about seperated batteries and power husbandry. olewill
 
Re: Jump starting

i saw the video of him doing it on the tele a few years ago, he was a frenchman on one of the round the world jobbies,
 
Re: Jump starting

Won't work on my engine. I had forgotten to put the engine in gear one day and we were doing about 7 knots (which is more or less our maximum) and wondered about the growling noise. Realised the gears were in neutral and engaged it stop the prop, which it did. The engine never moved.
 
Re: Jump starting

Crewed a JSSC Nic 55 back from Weymouth one year. Waves weren't particularly big but enough to make her surf occasionally which would then bump start the engine. Amusing at first but after the 6th or 7th time we just left it in neutral and listening to the shaft turning, so can be done but needed that extra speed.

Pete
 
I've done it with our 2 cylinder 12 h.p. Albin petrol engine (the collar engaging the crankshaft dog had worn). Two turns of a rope round the flywheel, block on the boom, bucket on the end of the rope and overboard it went. Took two or three attempts but start it did. Need to make sure there's a stopper in the rope end.
 
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