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davef
11-24-2003, 08:23 PM
Greetings. Stupid basic woodworking question. I am looking to make a "splash shield" (I know this has some correct nautical name... coaming??) to prevent water that sloshes over the bow from cascading into our cockpit. We're proposing to make the shield out of ash which will be planed to about 1/2" thick and then formed to mate along the front of the cockpit which is curved at a gentle (100" or so) radius. Because of the curvature of the deck, it would be uneconomical to make the shield out of a single piece of wood. I could however, easily make it out of a longer piece of 6" wide wood that had been joined to form a wider section. I know... I know.. there are correct terms for all this stuff. Sorry. Anyway, I could "join" two pieces of 6" wood at the centerline of the boat (see picture three below) but the joint would be right in the middle and the axis of bending would seem to want to fracture the piece right where it's joined. Alternately, I could make this out of three pieces of wood (one for the center on top and then two on the sides below).

How would one best create a single wide piece out of 6" wide ash? How would I make the joint so that it was strong enough to resist the forces generated in bending it to match the cockpit? Please assume a very novice level of woodworking!

Dave

http://www.imagestation.com/picture/sraid89/p815a433e3bd735563ed0fbb3b8416892/fa794249.jpg

http://www.imagestation.com/picture/sraid89/p398f60ef42777db73e609d11f4b08690/fa79424d.jpg

http://www.imagestation.com/picture/sraid89/p398f60ef42777db73e609d11f4b08690/fa79424d.jpg

davef
11-24-2003, 08:33 PM
Oopss.. Brain cramp spaz. I posted the second picture twice. Here is the third picture. I should have clarified that I intend to BEND the shield longitudinally to fit up tight against the curve of the front of the cockpit, but CUT the shield horizontally to match the curvature of the deck. I am assuming that bending it to match both the cockpit and the deck would be a hopeless pain.

This, therefore is half of the "flat pattern" of the shield when "unwrapped" off the front of the cockpit. As you can see by the crown, it's too "wide" to make out of one piece of lumber without a lot of waste, but could be made from two or more that were joined together using some secret manner which I'm hoping you will share.

http://www.imagestation.com/picture/sraid89/p78c159c972298a292f15025842ff2d1c/fa794245.jpg

John Bell
11-24-2003, 08:33 PM
Why not make a v-shaped guard like an old Sunfish? The center joint is a simple compound miter.

Paul Scheuer
11-24-2003, 10:37 PM
I think John means up on the deck, in front of the cockpit, Dave. Any water coming over will get diverted just the same, and you don't have to worry about sealing the vertical joint at the edge of the cockpit, or losing the deck as a seat.

John Bell
11-24-2003, 10:49 PM
What Paul said. smile.gif

John B
11-25-2003, 12:11 AM
What John said.
and Paul.

I need a splatter shield I'm so funny. Not.

I've been wondering how you are going with the boat Dave. Love that hull. Nothing else to add about the splatter sheild tho. I mean spray rail.
It's either laminate or steam I spose.

Jon Etheredge
11-25-2003, 10:57 AM
I know this has some correct nautical name... coaming??
Yeah, I'd call it a coaming.


I should have clarified that I intend to BEND the shield longitudinally to fit up tight against the curve of the front of the cockpit, but CUT the shield horizontally to match the curvature of the deck. I am assuming that bending it to match both the cockpit and the deck would be a hopeless pain.
I think you will find that it is impossible to bend a 6" wide piece to match the (vertical) curve of deck.

I agree with your first sentence. Saw two pieces to match the vertical curve of the deck (one for each side) and bend the pieces to match the longitudinal curve of the front of the cockpit.

How would I do the job?

1) Start by making an exact pattern out of thin plywood. If your drawing is really good then you could use it to make your full size pattern but it is safest to make the pattern directly from the boat. It is always safe to start by making a pattern smile.gif

2) Take a piece of your 1/2" stock and (carefully) test it to see if it can be bent into place against the front of the cokpit without breaking.

3) If you can bend the piece in cold, then use your pattern to determine the angle between the two straight sided pieces that will make up the two sides and then scarf the two halves together at that angle.

4) After the glued joint is fully set up, lay your pattern on your stock and cut to shape. Fit it to the boat and you are done.

If you can't bend the piece in cold then it gets more complicated. Two options are steaming and laminating. Maybe you can ask about that if you find that bending the piece in cold won't work.

An alternative to the scarf joint is a butt joint with a butt block either on the inside face or the outside of the coaming (or both if you like).

The Vee shaped coaming suggested by others would also work if the aesthetic is acceptable to you.

Jon Etheredge
11-25-2003, 11:28 AM
I forgot to mention in the last post that you will want to be careful with those square cornered cutouts when bending the finished piece into place. This is especially true on the outboard ends where you have a cutout to allow the coaming to extend over the side deck. The square corner may have a tendency to start a crack.

If the curve that you are bending the coaming into isn't too severe then you should be okay. The more severe the curve the more likely you will have problems.

I would recommend a fastening be placed vertically into the end of the coaming (possibly up from the under side of the deck) to keep those ends from flapping around and breaking in use.

gary porter
11-25-2003, 12:08 PM
Dave, I like John and Paul's idea but would also consider making it out of some nice Okume. I would be easy to saw out to fit the shape if you want to keep it as drawn. It would finish nicely clear or painted. You could even trim it out with a nice solid cap perhaps of your ash. Just a thought you know.
Gary

Jack Heinlen
11-27-2003, 02:03 PM
Typically a boat like this would have a low coaming the entire length of the cockpit, rising a bit forward, terminating in the v-shaped and angled outboard arrangement already dicussed--sometimes continuous and steamed, sometimes seperate pieces.

The problem with what you have drawn is that think it's still going to allow a fair amount of water into the cockpit. The problem I see simply putting an abreviated coaming on the fordeak is I fear it would be in a vulnerable spot for getting tromped, and wouldn't have any support at its aft ends. With a small 'stem' at the forward vertex, the aft ends secured to the side coamings, and all it well fastened up through the deck, you'd have a considerably stronger structure, that would be relatively easy to build(as opposed to steaming the forward ends of continuous pieces). You'd also have the added benefit of a little extra freeboard along the length of the cockpit. It would do a better job of keeping the water out than the athwartship arrangement you've drawn and Look better, abeit with considerably more work.

My 2 cents.

Just had another look at the boat, and continuous pieces, steamed on the ends are definately out. Look at the camber on that fordeck. smile.gif I also had a look at a photograph of a Lighting. It has very short coamings along the cockpit. The v-shaped piece is fitted into a truncated v shaped notch cut into the deck, going forward of where the side decks end, thus giving them much better fastening than going up through the deck. If that makes sense. A little difficult to describe.

Good luck.

[ 11-27-2003, 03:22 PM: Message edited by: Jack Heinlen ]

Ian McColgin
11-27-2003, 02:16 PM
This sort of forward combing is usually made of two pieces, meeting at the middle, with a butt block on the inside to spread the stress of the screws pulling it into a deck frame that is just at the foreward most part of the cockpit's arc.

It will look nice.

G'luck