Power Sailing - Useful or just fun?

[drams_1999]

So I was out in very light winds this weekend and decided to powersail (run the engine with main and jib out).

I have always heard this can be done to increase fuel economy.....to be honest I don't beleive it does anything other than allow me to "sail" while the motor pushes the boat fast enough to create its own wind.

....so I think "powersailing" is just something I do to let me have fun with the sails when I would otherwise be motoring.

I am wondering how others feel about powersailing.....does it actually have a practical use or is it just something we do for fun?

Does it increase fuel economy when conditions are right?

Opinions? Thoughts?

Fair winds.....

[RobertB]

It looks good

[Russ]

The boat cannot make its own wind. Moving under power may fill the sails, but if there is no wind, there is no wind.
Motoring with wind can help fuel economy if there is actual wind in the sails. Just let out the sheets and watch your speed drop. That's what you are gaining. Have you seen these ship kits that supplement propulsion.

I often do this because I'm too lazy to drop the sails. Sometimes blocks the sun also. Makes others think you are a great sailor by moving faster than they are.

[Phil M]

On a lazy afternoon with very light airs I actually gained a tiny amount of speed with the sails up on a close reach.

[NiceAft]

The boat cannot make its own wind. Moving under power may fill the sails, but if there is no wind, there is no wind.
Motoring with wind can help fuel economy if there is actual wind in the sails. Just let out the sheets and watch your speed drop. That's what you are gaining. Have you seen these ship kits that supplement propulsion.

I often do this because I'm too lazy to drop the sails. Sometimes blocks the sun also. Makes others think you are a great sailor by moving faster than they are.

Russ,

Best documentation I have seen yet.

Ray

[EZ]

When powering at low speed in rough weather (swell greater than 4ft) I find rolling out some jib reduces the rolling and the boat feels less tender.

I am sure there is a fuel consumption benefit, but I have not measured.

[hschumac]

There was a great article on this topic in Sail Magazine last year: http://www.sailmagazine.com/boat-handli ... torsailing

[NiceAft]

There was a great article on this topic in Sail Magazine last year: http://www.sailmagazine.com/boat-handli ... torsailing

Very good article.

Thanks,

Ray

[dlandersson]

Kids like that - they don't know why - they just know they are 'beating" the other boat. lol

Makes others think you are a great sailor by moving faster than they are.

[mastreb]

I suppose I could test economy while motor sailing this summer--I get real-time mpg on my plotter from the engine ECU.

I put the main up to keep the boat from rocking while powering in chop. Works a treat. I also have been known to dip the iron genny when I'm making too much leeway towards the quay in the narrow parts of the bay.

[drams_1999]

Thanks to all for the responses!

I especially enjoyed reading the article.....next time I'll release the sheets and see how much my speed drops.

I always appreciate the wisdom I find on here.....safe journeys to all!

[Ammiraglio]

I don't think it's quite correct to say that the boat does not make its own wind. The engine and propeller thrust -will- generate speed for the boat, and wind for the sails. In turn, this wind -will- generate aerodynamic forces on the sail. If, on average, these forces have a component toward the bow, then they will generally help the engine and make the boat go faster (there are other factors, e.g., how close to hull speed, variable vs. fixed pitch prop, etc.). If the average component is toward the stern, then aerodynamics will fight the engine. This just as a general principle. For more details, one needs to do actual calculations -- the article cited has very nice qualitative explanations.

Roberto

[mastreb]

Motor-Sailing can help you turn a very light wind into some forward advantage. But the assertion that if there's _no wind_ then motor sailing will not create useful wind is 100% correct. It will make wind, but all of that wind's force goes to drag with none to lift. If you plot the force vectors on graph paper, you'll see this effect clearly.

Now, if there's a 2 knot true wind, you can probably take better advantage of it motor sailing than just sailing, especially if you intend to actually get somewhere.

There's no case where you can actually turn true wind into greater forward force by motor-sailing than by just sailing, if you're sailing perfectly correctly for the wind speed. That said, it is easier to turn a light wind to advantage by motor sailing than by "just sailing". Light-wind sailing is quite difficult and punishing of helm mistakes, but I find it to be an enjoyable challenge, and it turns out that Macs are better at it than keelboats. With winds under 6 knots, I overtake keelboats all the time.

The purpose of motor sailing is to stabilize the boat and to reduce fuel consumption when motoring, not to create wind for sailing.

[Wind Chime]

I don’t know if this has already been mentioned in this thread, but I will throw out a reminder about motor sailing a Mac.

CAUTION: Motor sailing is safe only at speeds below maximum hull speed. (about 7 knots)

Model 's and ’s with sport hulls and larger engines can reach speeds above the maximum theoretical hull speed of about 7 knots. (5 x 1.34)

So these models are both a Sailboat and a Powerboat.

In general, when traveling at speeds;
- below hull speed: all sailboat rules apply. (keel & rudders down, sails up, etc.)
- above hull speed: all motor boat rules apply - under motor. (keel & rudders up, sails down, etc.)

With some exceptions like surfing downwind under sail (Nantucket), etc.

Darry
“Sail Safe, and Leave Only Wake"

[ronacarme]

On passage with need to get to port by a given time and a too light wind on the beam to give enuf sailing speed, we sometimes motorsail. Rather than stow sails and merely motor at 5mph or so cruise speed (our X carries a 9.9 Honda), we leave sails up and run the motor at a below normal throttle setting and sheet in till the telltales are happy. The result is motorsailing close hauled at the same 5mph but with lower gallons/hour fuel use, much reduced motor noise, and reduced rolling in the wakes of power boats speeding past.....a much more comfortable ride.
Ron