TOPIC: Stringer scarf ratio ?

Hi All,
I have an old 11' amusement ride boat with portions of the stringers missing. The stringers are 4" wide 1" high. I know in plywood terms the scarf overlap is 10:1 on the thickness. Is there a ratio for hollow core fiberglass ? or is it as simple as a 45 degree cut ?
Also, what has been used as a form backer for the new stringer ?
Does Home Depot ridged styrofoam melt when in contact with the fiberglass resins ? I would think if I used Polyurethane foam and water gets inside, it would be absorbed by the foam ?
your thoughts and expertise are greatly appreciated.

I would use more than a 45 degree cut. Stringers need bending strength. If it were for wood, I'd probably look for at least 5:1 and screw and glue the joint. Not quite sure how you want to scarf "hollow core fiberglass"? Some pics would be helpful.

Not too sure what you mean by scarfing a hollow fiberglass stringer? I'd need to see pics.

The insulation foam that you get most places is melted by poly/vinylester resins, usually not epoxy.

If you use the right closed cell foam, you won't have to worry about absorbing water, they are closed cell.

I'll try to get some pics out next week of "the wreck" I haven't started on it yet, just getting some up front questions asked, so I know what kind of supplies I'll need.
Now that I know I need closed cell foam for the core material to hold the stringer shape. How much material needs to be glassed to the hull ? 3", 4" or more per side of the stringer ? I'm planning on getting a roll of mat, cloth, and maybe roving too ? I'm just trying to figure what width I need ? Because I believe the present stringer is 1x4, so that takes up 6" of width already, so I'm guessing 12" wide to give 3" either side of the stringer to the hull ?

Well, I'm trying to post some pics. I have .jpg files, and I tried to save the .jpg to a .img, but I don't have that option.
You can call me a computer idiot if you'd like. But how to I convert these files ? Any help will be apreciated ?

You don't have to conver jpeg files Chuck, but they do have to be under the size limit. Here's a link to a post in the support forum I think you will find helpful;
www.fiberglassics.com/glassic-forums/7-support/22256-how-to-post-pictures.html

See if this works ? when I preview I see no picture. I did a resize too...

another: still playing here. Don't know if I get multiple pics at once ?

You can do multiple pics by posting with one, then hit the edit button and add another, as many times as you'd like.

try for multiples again ?

All I see is submit preview and cancel. I looked at all the icons above and none of them are edit. The brouse for inages just keeps changing the image when I try to add others. Where is the edit button ?

I'm sorry Chuck, I should have been more specific. You post the message with the first pic, THEN hit the edit button to add more. If you'll look at any of your previous posts, there should be an edit button available to you (since you were the author).

Ok, I see it now. Thanks.
As you can see the back potion of the deck has caved in and cracked. The problem lies with the fact that the rectangular hole in the far stern should not be there, and when that hole was cut, it goes right through one of the rectangular fiberglass deck supports. Long story short, I will be fixing hull stringers that are missing or cracked, but I will have stiffen up the deck first, by fixing the hole and stiffener support. So my first question is : Once the hole is fixed,
will the deck be strong enough on its own ? Or will I have to make all kinds of bracing when I remove the deck ?