AD41: Winter season thoughts

ostria

ostria

Well-Known Member
Joined
5 Dec 2005
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118
Location
Athens, Greece
dalexo.blogspot.com
As long as considerable amount of hours added on the engines this year (not yet over) i would like to share some thoughts with you to get (as always) the forums most valuable feedback.

My boat is a 32ft Regal with twin AD41s and has several heavy add-ons, such as genny, extended swimming platform and a heavy hydraulic gangway.

Part 1: Fuel consumption. The figures i came up with show something about 3lt per nm. Including trips with some amount of fouling on the drives, trips with clean drives, different weathers etc. More or less an overall average. Is it something i should consider reasonable?

Part 2: Smokey volvos.I know AD41s ARE smokey, but have heard that once they get warmed up they are not. What i get is lots of smoke while trying to plan, after that all ok. If however while on plane i try to reduce revs without getting off plane and push the throttles again, they ...become smokey again!! Is that normal as well?

Dimitris,
Athens, Greece.
 
I have twin AD41s in a Sunseeker Portofino 31. I get about 2 litres per mile and a bit of smoke on start up. Otherwise don't notice anything. Mind you, my exhaust is underwater. Every diesel I have used will produce smoke if you back off the revs and then floor it.
 
Most old technology diesels will smoke during acceleration ( the same principle is used to smoke test vehicle diesels) its because the pump injects more diesel, but because of the load on the props the engine can't speed up instantaneously, so the excess unburnt fuel shows up as black smoke, once the engine rpms pick up so that the amount of air and fuel is correctly balanced again they generally run clean. Going up on the plane is when they are most heavily loaded as the engines often need full power to push the boat over the hump, and as soon as the boat climbs over the hump and the bow drops the speed picks up dramatically as the load is reduced, and then you can reduce power and easily stay on the plane.Simply speaking.
 
Once owned a diesel montego. Acceleration was, shall we say, poor. However, if someone tailgated you, you could push the pedal to the metal (without any risk of tearing off down the road) and cover the following vehicle with a dense cloud of black smoke.

So I'm told anyway.

Not that I ever did, you understand. /forums/images/graemlins/blush.gif
 
We are just the same. Smokey at start up and then clean except for a few seconds going onto the plane.The fast cat Portsmouth service does the same except in a huge cloud of black smoke!

Dont worry - feature of the engines!! /forums/images/graemlins/smile.gif
 
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