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Closet Powerboater
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I confess, I'm confused about motorsailing. I hear it talked about a great deal, especially with ocean crossings and the like. I've tried motoring with the sails up a few times, and in my experience it doesn't work. I'm quire sure I'm not doing it right....

I've tried it as a means to burn less fuel, when the wind is light and I fire up the motor. What invariably happens is that the apparent wind under motor is dead ahead and boats don't sail directly into the wind do they? So the sails flop about and are useless.

In theory I can imagine it working if you had 10kts on the beam, and you motored forward at a few kts. The resultant apparent wind would still be off the bow enough to sail close hauled. But in that case, when you have 10kts on the beam, why fire up the motor at all???

I know I'm missing something fundamental here....

MedSailor
 

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Medsailor, I don't have a huge amount of experience and I am only weighing in because I motorsailed a couple of weeks ago with good results. I was returning to Channel Islands Marina from one of the Channel Islands with a beam wind of about 20 knots. Normally a nice setup, but I had had some trouble the day before (check the bonehead-moves thread if interested). Anyway, I motored with one reef in the main, traveler let out, no headsail, and made it back in 3 hours - a new record for me.

With my limited experience, I believe that I gained stability with the sail up, while allowing the motor to do some work as well. I might motorsail back everytime from now on with my family, as they start to get a bit antsy after a trip.

Hopefully, you will hear from some more experienced folks.

Cheers, Bill
 

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I motorsail all the time when the winds are light and I need an extra boost of speed. If the wind is on the nose and my sails are luffing, I either change course a bit to fill the sails, or take them down. Ideally, the wind and the motor are working in harmony to push me along.
 

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If the wind is dead on the nose, motorsail under Main alone with it sheeted in tight and the traveller all the way to windward. If you can crack off a bit, then you can use the headsail, usually not though as it gets backwinded from apparent wind. I find that motorsailing in rolly conditions does add stability to the boat.
 

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Motorsailing only works if you can actually sail without the motor first, albeit slow. If there is no wind or your dead into the wind, the sail isn't doing anything to propel the boat and actually is acting a little like a brake when motoring.

Motor sailing works like this:

Let's say there is 5 kts of wind abeam. Without the motor on, your boat does 2 kts with the sails up. Without sails up, your boat goes 5 kts at say 80% throttle; actual number/% is probably different. Putting the sail up and the motor on allows to say go 6 kts at the same throttle setting or the same motor only speed (5kts) at 50% throttle (instead of 80%). However, as you go faster, your apparent wind angle will change and you will need to adjust for that.

Also, if your boat is heeled past a certain point during a motor sail, you may be starving your engine of lubrication. Remember the oil pump in your motor needs oil to pump it to the top of the motor and if the oil is all to one side of the motor during heeling, it may not be pumping to the top of the engine.

My rule of thumb is if there is no wind to sail to my destination at say 4+ knots a AND it need to be there in a certain time frame, it's just easier to drop the sails and motor at 5+ kts. If I am not on a time table and as long as the boat can be sailed and not just drift, I don't use the motor.
 

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Motorsailing significantly reduces fuel consumption, because the sail(s) generate power, which supplements the engine's power and enables you to reduce engine rpms and still maintain the same speed.

A couple of years ago, I was crewing on a boat with a tired old A4 engine, and it had a broken gooseneck, so we couldn't raise the mainsail. Motoring to windward against 15-20 kt winds, it could hardly make any headway to windward. When the waves smacked the bow, the boat shuddered almost to a stop, and we finally had to give up, turn around and go back. But, on other trips, when we could motorsail, we could drive it to windward against chop in 20-25 kt winds with a single reefed mainsail.

I have experimented with motoring directly into the wind while my friend, on his boat, motorsailed off the wind enough to fill his mainsail, and, even though he traveled a slightly longer distance, his greater average speed and fuel savings made it well worthwhile.
 

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Motorsailing, especially when going upwind, adds to the apparent wind flowing across the sails; hence, increases the power of the sails while consuming little energy (when in light winds).

Motorsailing in 'survival' conditions is also a help to keep the boat moving when powering through BIG oncoming waves that would otherwise stop the boat dead ... but you have to be sure that the engine when the boat is at maximum heel will be still pumping oil and that the suction side of the oil pump remains flooded (see you engines spec. sheet). These would be conditions when the engine alone could not power the boat into wind/waves all by itself.
 
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