Auxiliary Engines, Again!
Spotted a few RIB’s and hard boats in various harbours in Minorca with some neat solutions to mounting auxiliary engines and folding ‘Bimmi tops’. Unfortunately I didn’t have my digital camera with me each time so can’t really pass them on.
Interestingly every boat had an auxiliary engine or twins on the back, they obviously do not have the emergency back up we do, so need to ensure they can look after themselves.
One sports boat of only about 6m with a Mercruiser inboard engine was very interesting, the owner opened the engine bay to show me the solution of which he was obviously very proud.
It had a Yamaha 50HP on an auxiliary bracket on the Transom, connected up to a separate steering wheel, fuel tank, and remote controls with PTT all located inside the main engine bay. The engine had an over centre type strap on it fixed down to an eye to stop it bouncing about. The owner could prop open the engine cover and drive the boat from the rear bench seat in relative comfort. A bit OTT, but a great solution for an inboard equipped boat.
Now to start a discussion.
Imagine a similar set up on a 150HP outboard equipped 6M RIB with the extra steering set up for the 50HP on the front of the transom but reversed to steer the right way.
Here are my thoughts.
With say twin 90HP’s, you get maybe the equivalent of a 150HP single but use more fuel. You’d need 2 separate fuel systems, and how often do you see a back-up steering system. If one engine goes down, the remaining engine will struggle to get a loaded boat up on the plain, so will use loads of fuel labouring the boat through the water.
You are also using both engines all the time, so both need servicing etc.
If the single 150HP goes down the 50HP will still not get you on the plain, but will it use less fuel pushing the boat through the water than the remaining 90HP above?
Also, will the 150HP single use more fuel carrying the auxiliary 50HP around all the time than the twin 90hp’s will use anyway? I think it’ll use less.
I wonder what weighs more, the 150HP plus 50HP or twin 90HP’s?
Could you counter balance the offset auxiliary 50HP by stowing enough gear and auxiliary fuel on the opposite side of the boat?
RIBBED For extra pleasure.
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