Weather Handling

[davegnvl]

We had our first bareboat charter last weekend on a 39 foot Beneteau on Galveston Bay, normally we sail a 26 foot Pearson on a large lake.

On Sunday - winds were 15-20 kts and we sailed w/ full mainsail and full genoa and clipped along at 6.5-7.1 kts very comfortably. We had a modest heel but for rookies felt good and enjoyed ourselves greatly. The sea was a little choppy occasionally with rare white caps.

On Monday - the sea was choppy with small waves, winds were consistently around 20 kts. It felt a lot rougher even though our gauges said it was about the same wind, so I set sail with a double reef on the mainsail and only put out about a 50% foresail. On a beam reach we still were hitting > 7 kts with that set up. It was work to keep the boat on a heading.

My question to the experienced out there - why did we experience such a vast difference in the feel with basically the same wind and only modest increase in the choppiness of the water? Sunday was a lot of fun, Monday was a lot of work.

[swagman]

Could have been tidal influence - could have been the way you set up your sail plan. Most likely a combo of reasons.

On day one maybe wind with tide giving flat water hence good control and speed?
Day two maybe wind against tide giving chop which could make it feel a lot worse?
Plus there's a lot of difference twix 15 / 20 variable and 20 knots of solid wind, they are not basically the same.
Plus smaller sails might indeed give greater speed maybe but we less well balanced creating more work.
It is a good question but the reality is without someone being with you both times, going to be tough coming up with the right answer.
Enjoy.
JOHN

[Jolly Roger]

Swagman hit it right on the nail. To many variables to answer the question with certainty. That's what experience is all about.

[Sandero]

I find that in the windspeed range of 15-20+ it's the sea state which dictates how the experience is. When you work with larger waves the boat is pushed around, apparent wind is moving for and aft, sail trim goes in and out, motion is bumpy, steering is more demanding.

A beam reach can be sailing up wind or downwind or even BOTH depending on your sail trim and this point of sail is very much subject to riding up and down as the seas are on the beam.

When the winds subside and the sea is still running or confused it is worst of all.

[imagine2frolic]

If the white caps were rare. I would think the gauge is off. Anything over 15 knots they will be very noticable. Nice move on reducing sail.........i2f

[Eleven]

I'm having the same trouble as I learn my new boat.
First off i find trouble reducing sail area because it unbalalnces the for/aft water balance.
I use the boom track to get the balance to give fairly neutral helm then things improve a bit.
I'm not sure part rolled genoa's do very much, the air stream breaks away too easily. I've got more work to do there on trimming/ shaping the sails to be fuller and smaller to be more forgiving with pitching upsetting the working angles all the while.
My book talks about un-bending the mast to make the main fuller, and adjusting the genoa tracks for/aft to allow more belly there. All very confusing untill it comes together, and very hard work when it doesn't. Mono's don't seem to have so much trouble because they don't veer about so much. Feels like inadequate rudder area when it's all wrong. Horrible and worrying but I don't let on too much. I'll master it sooner or later. Or at least get to grips with it.
Incidentally a recent trip on a BB385 in f6 against strong tide we had the same trouble. Unable to hold a course into wind with constant veering into wind, then falling off thirty to forty degrees again. Slow trip in unpleasant seas. Mono instructor didn't resolve it either. Practice, try, practice. Just need lots of water space and energy.

[Sandero]

You don't see white caps until the winds have been blowing long enough and the fetch long enough for the waves to form where the tops can be blown off.

In protected waters where the winds are not constant ... like the trade winds you can very well see rather calm seas, small waves with higher wind speeds. But over time with consistent winds from the same direction the wave height will build.

Currents can also cause waves to "trip" , become short and have their tops blown off (white caps). I find that offshore you don't see white caps until the winds are in the 20 knot range or they appear at higher wind speeds than they do in close to shore in shallower and certainly in protected waters.

I would put too much stock in the accuracy of marine annomometers. If ever happen to see a bunch of sailing yachts with AWIs in a marina when there wind is fairly light your notice that they are not all spinning at the same rate. They either use a different means to calculate the wind speed, or some are not reporting accruately as result of friction.

[GordMay]

Wave height is only a rough estimate of wind speed. Wave height is determined by three factors, wind speed, duration the wind has been blowing and the fetch, or distance, the wind blows over a body of water.

The best visual signs are white caps, spray, & spindrift*.

Estimating Wind Speed and Sea State with Visual Clues

Goto ➥ National Weather Service - NWS Portland
wrh.noaa.gov/pqr/info/beaufort.php

Whitecaps: Foam crests on the top of waves.
Spray: Water blown off the top of waves.
Spindrift: heavy spray

[Pblais]

My question to the experienced out there - why did we experience such a vast difference in the feel with basically the same wind and only modest increase in the choppiness of the water?

Gord gets to an important issue. In flat water it's easy. 20 knots is just normal stuff. In 25 with flat water it's an easy day. In 20 with more action in the waves it's not. You trim and reef to what you can manage not some ideal situation. When it gets harder it usually means it is. The wind was more than before and so it changes the issues. The sea state raises. A few knots of wind and a few more waves a little harder and suddenly it's real work. It's not only the wind speed. Wind force is a geometric progression not linear relative to speed. From say 17 to 20 gusting to say 22 it's a big jump. It takes a while to learn how bigger boats handle too. They don't respond like your smaller boat, but they suffer the same issues. It forces you to be thinking before it's hard not when it's hard.

[mesquaukee]

In choppy water or short seas the boat tends to pitch. If you look up at the top of the mast it is moving rapidly forward and then moving aft. It is impossible to trim your sail just right as the apparent wind angle is rapidly changing on the upper 1/2 of the sail. You have less drive and the boat feels sluggish and unbalanced, makes it hard to stay on a heading.

[s/v Jedi]

Originally Posted by Eleven

I've got more work to do there on trimming/ shaping the sails to be fuller and smaller to be more forgiving with pitching upsetting the working angles all the while.

If the wind picks up you want your sails to be flatter, not fuller. Flattening a sail de-powers it. So, increase tension on halyard (use cunningham), outhaul, back stay, vang (when down-wind) and sheets. Also, use the traveler for positioning the boom and keep the sheet tight. Let the traveler out a bit more to de-power even more. With full batten sails you need tell tales to check trim as you don't see luffing.

cheers,
Nick.

[davegnvl]

Thanks for all the replies. This is definitely a long term learning process.

[John Brewer]

The Beneteau 39 is very wide in the stern. When these boats heal the bow stays low in the water while the stern lifts. This produces a strong rounding up tendancy, while at the same time a large amount of rudder is lifted out of the water. In smooth water this is easy to trim as the boat is stable in the water. I waves it is very difficult to control. The only way to steer staight is to have the main sheet trimmed rapidly to maintain balance.