How to reduce spray?

[JeffM]

I've always been surprised at how wet my cs20 is. On any day with winds at or above 10kt, the kids sitting ahead of the thwart get pretty wet sailing to weather. One really windy day even I got wet and they were soaked through by the end of the first hour. I've considered a spray dodger, also a sort of upright spray shield that would be an upward extension of the coamings, keeping the whole cockpit open. Today I was out in 10kt winds with my sister and 5 kids. My spray shield idea seemed all wet as spray came over the coaming more than a foot high. I began to wonder: is there anything that can be done to avoid generating so much spray? (Short, that is, of slowing down.) For example, I've seen blurbs for lapstrake designs that tout the tendency of the laps to catch spray, keeping the cockpit dry. Does anyone have any ideas for a simple add-on that would keep spray below the gunwhale?

[mustangermatt]

I keep weight in the forward compartment which keeps the bow from slaping and pounding so much. It seems that alot of the spray I get comes from the forward part of the chine, not the bow. But this affects the ability to plane and when water does come over it is solid, not spray :-)

The best solution I have found is to keep rain gear aboard just like life jackets. On long trips up here hypothermia is a real danger if people get wet and are exposed to wind. This is also common practice on the bigger baots around here, especially racing when you can't srop sailing and send the crew below to warm up :-)

[ChrisObee]

Many power boats have spray rails. They are shaped like a right triangle. they are rails on the hull that are supposed to deflect spray away from the boat. They are mounted parallel to the chine and arc upwards near the bow. One leg of the right triangle glued to the hull, the hypotenuse side facing up. They are mounted slightly above the loaded waterline.

[Mike Vacanti]

Ray,

Will the CS 20 be for sale anytime soon? I spend way too much time lurking on several different message boards and I noticed an exchange between yourself and the owner of the CS 20 in question. He was asking about building a much smaller boat. Did he decide the CS 20 was too much boat for him?

[Terry Dunn]

Jeff,

To combat spray, I sit just aft of the mizzen thwart and position my wife just forward of me. Works pretty good. For some reason we have not sailed as much this year.

[JeffM]

Yup, Terry. My kids also have caught on that their chief role is that of spray shield for the skipper. But if they won't go out with me anymore, what will I do?

Ray, I look forward to the sailing tips!

Chris, I'd seen those strips on the bows of power boats and guessed that that was their purpose. I wonder whether they'd be worth experimenting with, and how I'd do it without mucking up my hull.

Matt, I might play around a little with hull trim, but I doubt it would make enough difference to be worth the speed penalty. Around here and at this time of year hypothermia isn't much of a worry. (But I was really careful to keep warm and dry when I had her out for three days in mid-April!) It's simply that sailing should be fun--and it isn't if you're under 12 years old (as all my kids are), soaking wet, and on someone else's adventure!

[Wes T]

Didn't Gordy Hill have spray rails on his CS17?

[Garry]

I think that spray rails would not be effective. On a powerboat, the hull is normally level. This would be true only downwind for a sailboat. It might work if you can get someone to go in another boat and see where the spray is coming from.

[Gordy Hill]

Yup! I put spray rails on my CS17. After trying to make them look a little nice they ended up looking a lot like 1/4 round molding. They were about 3/4 by 1/2 inch and not a 90 degree angle. This gave a kind of sharper angle with the bottom in order to catch some of the water rather than just divert it. I think they were much too gentle an approach.

It seemed that at slower speeds where I expected to start getting some spray I was dry. As I went faster I started to get wet and, although I feel I wasn't getting as much spray as usual for that speed , there's no way to be sure and certainly I wanted to think they were working.

My 16 foot welded aluminum center console had exactly the same problem. On a lake it was wonderful, but off shore it could be terribly wet. I wanted to have spray rails welded on and then saw exactly what I was thinking of on a flying boat in a museum! I got some 3/16 x 1 1/4 aluminum bar,and after some time trying to work a machine with two wheels that bend the bar along the width, we came up with two pieces about 4' long that matched the forward part of the chine while slanting down to about 30 degrees off vertical. We then used some 3/16 x 5/8 and kept tacking it while we bent it into shape. It ends about 18 inches short of the transom because that's how long our bar was.

Not only is there a marked decrease in spray, but the boat rides noticeably better.

My theory, totally uncomplicated with actual data, is that a boat displaces water in a direction 90 degrees fron the section of hull displacing it. If you picture a horizontal flat it would send the water off horizontally, however, if you had a vertical flat, or dam, it would catch the water and actually give some lift to the hull. This is free lift. The water moving up doesn't remember it was displaced by your hull. It's just moving up and runs into your spray rail. Also, the water moving toward the sides of your hull farther back would be caught by the shorter spray rail and may actually let you plane at a slightly slower speed. Then again, maybe it wouldn't....who knows. I do know that if I still had my CS 17 it would have spray rails that would look a lot like the ones on my aluminum boat..... which I would have pictures of if I could learn to work my new camera.

[JeffM]

Dunno, Garry. It is true that I get spray over both sides of the bow. Ray, the windbreaker is my preferred outerwear, too--but I'm not the one forward of the thwart. Gordy, I'm picturing quarter round that follows the chine beginning a little ahead of the aft edge of the foredeck. Spray would be deflected outward and slightly downward. I suppose I could hang over the bow underway to fine-tune the location, and use just a few small screws until I got it just right. Pictures of yours, please!

[Gordy Hill]

Jeff,

I wasn't too impressed with the 1/4 round spray rail I used. It helped, but if I were to do it again I'd want something a bit larger and designed to send the spray down more than outward. I'd consider 3/8 inch plywood cut to follow the line of the chine and the top inside 3/4 inch or so planed to a point with that much again standing proud below the chine.

I think the spray rails should start much farther forward, say where the chine break first starts.

[JeffM]

Out yesterday in 10kt+ with a version maybe D of my dodger. It's about a foot high for the whole front of the coaming. Kept most spray out, but we only averaged about 3kt in about 6hrs of mixed sailing. My sense is that the windage is a big factor. So now I'm about ready to look seriously at spray rails.

[Scott Dunsworth]

Jeff it may just be something you will have to enjoy. A month ago the wife and I had our Belhaven out in some 15 to 20 mph winds and on the beat we were getting a small amount of spray over the cabin. Some actually came through the roof hatch. I guess thats why they make those hatchs to close. :oops:

Scott