First get a Suitable boat.
Yep, seems like what I needed to hear.Freewheeling a prop will almost certainly damage the gears and the shaft log. Locking the prop will almost certainly counter the effort of the remaining engine. In other words, too much drag.
Even in an ideal situation you will not save any fuel. It costs a fixed amount of energy to move a boat. Using only one engine will use twice the fuel.
Just run both engines
pete
Thank for that. Hull speed travel was said to double the mileage and I enjoy relaxed travel when the lake is calm anyway.Why would you say that? I guess I don’t have a suitable boat either. We all have the boats we have for various reasons and there isn’t any right or wrong answers l. But there isn’t anything wrong with trying something to save fuel.
We have a planing boat and I find that running on one engine vs both doesn’t save a lot of fuel since the one engine has to be powered up more than if I run both. But individual boats do vary so if your transmissions allow it then give it a test.
Freewheeling a prop will almost certainly damage the gears and the shaft log. Locking the prop will almost certainly counter the effort of the remaining engine. In other words, too much drag.
Even in an ideal situation you will not save any fuel. It costs a fixed amount of energy to move a boat. Using only one engine will use twice the fuel.
Just run both engines
pete
Don't even take my word for any of it.....reasearch and then research some more.
Already someone misidentified your gearboxes AFTER you posted what it was.
Even then, some twin disc gears do NOT have to be started every hour. I owned a pair and ran many in Sea Rays that didn't.
The other thing is about running on one engine, if you try and run the same speed as on two...pretty much the same fuel consumption. But if you accept a lower speed on one, some boats have pretty significant savings, but the penalty is SPEED. This savings though is VERY dependent per boat...hard to generalize on it.
10+ years ago, Passagemaker Magazine ran an article about a guy with a GB42 who single-handed from California to Hawaii. To conserve fuel, he wanted to run on one engine. So he removed the prop of the other engine. This seems hard to believe even though I am pretty sure I read it - to balance engine hours, in mid-ocean, he removes the working prop and installs the prop on the empty shaft. Before he left, he backed into his slip so he would never have to go to reverse and he removed the prop-nut on the prop he used for the first half.
Small wonder he was single-handed. Sounds nuts to me.
Peter
I remember the story too. I would not try swapping props in the middle of the ocean by myself…
seems like the safe approach would be secure the shaft so it does not turn.
Yeah I was going to point out that you probably want to run a bit *below* hull speed, not right on it. Maybe 80% of hull speed - some more experienced folks can describe how to tell by looking at your wake. It'll settle down considerably as you come below hull speed & you'll burn less fuel for a very small speed reduction.
you know, sailboats run around all the time with an off engine freewheeling