Motorsailing- It seems like magic

[Bertie68]

Originally Posted by capt jgw

Ice boats do that too. Some can do over 80kn so even when sailing with the wind they end up close hauled. True wind 20kn on the quarter (they never sail dead down wind, that would be slow, no faster than the true wind speed) plus 80kn boat speed equals 60kn just off the bow. Scary.

Yes, if a sailboat had zero drag force, it would reach an infinite speed (only limited by the maximum close hauled angle) due to the 'compound interest rate'.
And that's why a clean hull is of paramount importance when sailing upwind: the increased drag of a dirty hull not only will slow initially the boat, but also the apparent wind will be slower and so on. Adding motor is actually compensating for drag, and even a little bit helps a lot.

[goboatingnow]

[pedant] by the way velocity is a vector as it always has direction , speed is a a scalar ! [/pedant]

[leecea]

I feel like my battens will hold the sail shape pretty well even if it's generating virtually no forward movement. When I was on boats with furling mains, they seemed to flap more.

In fact during a recent motor sail dead into the wind, I noticed the battens had taken on an "S" shape and the sail was stable that way. No flapping. But by then it's slowing me down rather than helping.

[Panope]

I added an alternate staysail sheet location, well inboard up on the cabin trunk. It's sole purpose is for motor sailing to windward. Works great.

[Don C L]

I often motorsail since we can have some pretty light winds here. I have a fully battened main and that does stay filled better than my other main, but I need to have at least a breath of wind somewhere off the beam to get it to motorSAIL not just motorluff. The other advantage, besides getting some drive off the sail with the wind you are creating, is the stabilization the sail offers to the boat, which is nice on my tender little boat.

[SoonerSailor]

You may be able to point higher because increased speed through the water improves the lift provided by your keel and reduces leeway. Sailing too close to the wind with a reduction in boat speed will increase leeway and your diminish course made good to windward.



As far as why your sails don’t luff as you go faster and higher with motor assist, I’ve observed that too, and am unsure of the explanation.

[JBsurfin]

Originally Posted by AuChante

I've only had the boat out a few times, and I've leaned toward the safe side and reverted to motor power at any sign of possible navigational dangers (narrow channels and such). I have always expected the sails to flap about like big flags, but it seems that the engine creates wind.


I'll be sailing as close as possible into the wind and it doesn't seem like enough to stay in the channel. I crank up the engine, and now I can sail 10deg into the wind. Or I'm making way at half a kt, crank the engine, pick it up to 5 kt, and the sails magically stay inflated and seem to be helping propel the boat (even going down wind).


What's happening here? If I'm going close to directly down wind at half a kt and crank the engine... the sails should deflate and flap about right? I'm astounded every time I start to motor.

'I've leaned toward the safe side and reverted to motor power at any sign of possible navigational dangers (narrow channels and such)' There are enough comments on what is occurring. I would say, move yourself away from fear. Maybe start your engine, leave it in neutral, and then try to sail through those tight spots that may bring some hesitation. Your confidence will grow and eventually not need to have that engine crutch.. Happy sailing.