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-   -   Motor Sailing to weather (http://www.sailnet.com/forums/general-discussion-sailing-related/64044-motor-sailing-weather.html)

labestia 04-20-2010 05:15 PM

Motor Sailing to weather
 
Assuming that we’re motor-sailing @ 5-6 knots @ 25deg to the wind in 20 to 25 knots of wind with 30knots gusts, 8-10+ foot seas, getting wet every minute and pounding like crazy.

How much can the ride improve if we continue motor-sailing but @ 45degrees to the wind @ the same speed and conditions?

Can the ride get “comfortable” with this change in angle?

I know that this will depend a lot on the type and size of the vessel but generally speaking…

Faster 04-20-2010 05:39 PM

If it's that windy at 45 deg you should be able to sail it and shut the engine off, and pretty much do the same speed or better.. IMO the ride will improve too...but you'll be heeling more which may not be great for the engine if you're still motorsailing - I know I avoid running at any significant heel if the motor's on.

nolatom 04-20-2010 05:45 PM

What sails do you have up? Reefed main? What sized jib?

Are you beating, or just trying to hold that angle on one tack until whenever?

"Generally speaking" 25 degrees will have both sails inverted along the luff, and with a jib you'll risk getting caught aback if you head up too far. Also, you'll beat up your sailcloth a lot with all that luffing. But the sails will dampen the roll, and help your engine along a little.

45 degrees will keep your sails "asleep", dampen the roll more, and make her a little easier to steer. Probably more comfortable depending on your bow geometry and the particular boat design. But more real estate to cover if you're beating.

And this doesn't answer which speed thru water is going to get you to ride the best, again that's design, and wave-period dependent.

Oh, and as Faster said, you have to be careful that your cooling water intake, and prop, remain submerged. Otherwise, just bear off and sail her. And be careful, if your fuel tank's like most, there's some gunk and junk at the bottom, and motoring in a real rough sea can shake it up into the fuel line, and thence to your engine/filters/injectors/carb. Now you don't have an engine, and it's too lumpy out to fix it safely.

sailjunkie 04-20-2010 05:54 PM

My previous heavy weather motor sailing experience was under main sail only, on a Catalina 27 with a 9.9 HP o/b. That went well, and our ride was definitely smoother.

We haven't tried it on the new boat, but I appreciate Faster's advice about heeling when it comes to the engine. Another part of the inboard learning curve.

Faster 04-20-2010 06:01 PM

It does depend on the engine, some have oil systems that are designed to acccomodate heeling to a degree.... but some don't. Others, for some reason, like to dump all the oil out into the bilge/engine pan if heeled too far on one tack or the other.. a messy lesson best left unlearned.

Ulladh 04-20-2010 06:03 PM

8 to 10ft seas are not that bad if long period between crests, if short period then sail or motor sail will be just as uncomfortable.

Reduce headsail to 50% or less and reef the main to 2nd or 3rd then assuming no bit of land in the way, find an angle to the waves that feels right. Keep the motor in gear at idle or not, you will be moving faster under sail than with the motor on.

Architeuthis 04-20-2010 06:14 PM

Quote:

Originally Posted by Ulladh (Post 595299)
8 to 10ft seas are not that bad if long period between crests, if short period then sail or motor sail will be just as uncomfortable.

Reduce headsail to 50% or less and reef the main to 2nd or 3rd then assuming no bit of land in the way, find an angle to the waves that feels right. Keep the motor in gear at idle or not, you will be moving faster under sail than with the motor on.

Ditto, try different points of sail to see and feel the differences. Sometimes I don't mind pounding through the seas if the crests are timed right, other times I would prefer sailing or motoring away from my destination rather than be uncomfortable.

I have doused the sails and just motored directly into the wind (+40knots) once and it worked rather well, little heeling, a bit rough but our destination was in that direction and we did make headway so ended up to the better after that little storm went by. Usually though the wind means sailing just with less sail.

Just try different things, those conditions are such that most sailboats are going to handle them just fine, it is just making things comfortable that matters...........unless racing in which case.....

Tempest 04-20-2010 06:21 PM

I'd agree with Faster. You'd get a better ride with some sail up between and working between 45 and 60 degrees. The boat won't roll as much. If you wanted to sail with a reefed main and the engine, that would be a compromise to reefed main and small jib. But I have found the engine to be annoying.

With 8-10 ft seas and 30 knot gusts, the wave period is what is going to decide your optimum speed is...at this point you're sailing the seas (1 at a time) looking for the right combination of comfort and speed. You might want to be heading up ( 45) into the waves and falling off (60) down the backs.

I wouldn't want to pound ( motor ) into these conditions at 25 degrees..for any length of time. My engine wouldn't push 5-6 knots against those waves and winds at that angle.

If you sail close hauled, you're likely to lose boat speed imo..the waves will knock your speed down and they will shadow the wind in the trough. Which is why, you might need to fall off to 60 degrees..on the back of the waves..to maintain boat speed and not bury the bow.

sailingdog 04-20-2010 06:37 PM

I'd point out that by sailing at 45˚ to the wind and waves, you're effectively lengthening the wave period, since you're taking them more obliquely.... this will make the boat's motion much calmer.

I would be hesistent to fall off much further, since you'd be more abeam to the wind and waves than heading into them and far more likely to get knocked down if you're not careful.

klem 04-20-2010 06:56 PM

If you are really trying to get somewhere directly upwind in short period 10' waves, you will generally get there quickest simply motoring provided that you have a powerful engine. However, the motion will not be comfortable at all as you will be pitching quite a lot.

How well motorsailing works really depends on the boat. Some boats really benefit from having the sail area to induce a constant amount of heel although VMG going directly into the wind almost always suffers.

The way that I usually try to handle this situation is to fall off until I can really sail which essentially makes the wave period longer and when heeled, the boat will stiffen up some. Part of the key to this is getting the correct amount of sail area up. Overpowering is pretty obvious but I see a lot of people in this type of conditions underpowered which leads to greater rolling and often requires the engine to keep speed and steerage.

Probably the best thing to do is to try each method for 10 minutes and see what works best for the given conditions and boat.


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