Engine damage from motorsailing?

[boris]

bukh recomend a max of 30 deg

[Hampus]

Hey!

I don't have the meanual in front of me, but I know they mention it (Yanmar 3GM30F). If I remember correctly, they said no more than 10 degrees continuosly. They never said why though. I've done more than that though, and if it's a good installation there shouldn't be any problems. A few things come to mind though. It might be a good thing to run at a higher rpm if heeled a lot, to keep pressure up, especially on an old engine. Oil pressure isn't the only thing to take into consideration, also the cooling system. A poorly installed expansion tank might actually end up below the engine. Also if you have a water heater and it isn't placed in front of, or behind the engine, but on the side, the water pump might have a hard time keeping the flow up.

[easterly]

The Perkins manual states 25 degrees of heel maximum. Don't run your Perkins if you are heeled over more than 25 degrees.

[AnchorageGuy]

Whatever the manuals state we have motorsailed for hundreds of hours with our Yanmar with NO oil issues.

[Therapy]

We overheated a Westerbeke because the water intake was out of the water too much.

[AnchorageGuy]

Originally Posted by Therapy

We overheated a Westerbeke because the water intake was out of the water too much.

Now that is a good point and an issue we also ran into. But all we did was move the intake thru-hull low enough to make it so only if the boat is upside down will this happen again.

[Boomp]

Took a weekend diesel seminar last year. The fellow who ran it said to avoid running the engine at more than 15*. The oil in the sump could be picked up and you end up with a runaway engine and the only way to stop it is to plug a raincoat or your hand into the air cleaner. I don't want to ever have to deal with that! He said if you use your hand you risk a big hicky...naahh don't want that!

[Pelagic]

I think perhaps the issue would be if you heeled over sufficiently and there was no other motion for you to scavenge out from the oil sump. Which is not the case at sea where swells and waves rock the engine

Also Marine applications have deeper oil sumps to begin with because of the expected angle of heel

I Motorsail with my Perkins 6.354.4 M series all the time at low RPM when fully pressed with headwinds.

1993 installation and recent compression check showed all cylinders just below optimum. We burn no oil between changes

[S/V Illusion]

Surprised no one has asked why this is even a reasonable scenario - if there is sufficient wind to heel the boat significantly, why run the engine?
I guess the only plausable scenario I can imagine is battery charging but, as it is possible to drain the sump beyond the pick-up tube, I can't see why anyone would do so even under that circumstance.
This certainly seems to be one of the more academic issues here...

[Ziggy]

Originally Posted by never monday

Most of the engine builders will publish a deg of operation for a given unit. From memory, most being 20*

According to the Yanmar installation manual, the max. athwartship inclination is 20 deg continuous, 30 degrees peak. Max fore-and-aft inclination is 20 deg continuous, 25 deg peak.

[Chief Engineer]

I have absolutely no opinion on this.....I either sail or motor.....don't do both

[cooper]

The greatest angle I have seen "that is OK" is 35 deg.
I have a watch dog on my engine that shuts it down if the engine is "stressed". (Good old industrial not marine technology.) It has a manual override at a flick of a switch. You check the guages and find out what the problem is, assess the danger of being without an engine and make your decision. If it is heeling to far while sailing, then a quick easing of the sheets is all it takes. If you are desperately trying to save your boat from a lee shore in a gale...you make your own decision then....

[Alan Wheeler]

It takes a huge angle for oil to be picked up somewhere it shouldn't. The damage would have been already done by the oil pump losing pick up before then.
Motor sailing is the hardest thing you can do to your engine. It is like idling out of gear and death to an engine. If you motor sail, you certainly want to work the engine hard when ever you have the chance to do so

[Pelagic]

Pretty hard to avoid Allan if you are a motorsailer by design.

On long passages I need to motorsail to keep the batteries up from the autopilot draw.

Engine only I need about 1600RPM for 8 knots
I run between 900 to 1200rpm if I have any kind of lift from the sails and I am doing 8 knots

Back to idle 650rpm and the speed will drop to 5-6 depending on wind.

I am big and heavy (40 ton) with a conservative rig and it is not a boat I use as a day sailor so I don’t think I can avoid it..I just need to make sure I keep about a 2knot speed load on the engine by furling earlier in higher winds.

That is one of the reasons I upgraded from 400Ah to 1040Ah in house bank, to see if I can manage this better and get back to pure sailing (with conveniences).

[Alan Wheeler]

She's a beautiful boat Pelagic. I think your engine will be working a little harder than most. However, it is good to do two things. Every time you have motorsailed for sometime, give the engine a good hard work for a few minutes and either continue to motorsail or shut the engine down. It just helps to keep the cylinders valves and exhaust clean. Just before you shut down anytime, give the engine a good rev and then pull the stop cable. This helps to get rid of the slightly heavier oils that can sit in the exhaust system and cause a bit of blue smoke at start up from cold.