Most Important Places to Reinforce on a 45"+ SAW Cat?

[dmitry100]

So I think my hull isn't exactly reinforced like I would like it to so I plan to make some thick Kevlar sandwiches at the seams (and some 3k Carbon cloth over it for looks.)

Are there any other problem areas that I should look into reinforcing when it comes to SAW cats? Are seams at the rear of much importance?

All the pictures I've seen of damaged cats are of those in the front sponson tips and the seams that are at the very front of the tunnel ... is there any good way of reinforcing in that area?

[srislash]

You can roll a little acetone in the nose to prep and then try to get some CF cloth strips up in there. I have been reinforcing the decks for some time now with basically stringers out of light CF sheet. A little brace on the rear deck area can’t hurt.

[dmitry100]

shawn, is there any good reason to use kevlar over CF for sandwiches? I sort of assumed Kevlar was going to be lighter, stronger but Solar composites doesn't appear to show any strength details for kevlar. Figured I'd just use some 12k CF cloth instead.

[srislash]

Well I think Kevlar has flex to it so I am not sure the two should be used together. I am sure combined Kevlar/CF will hold together better but the epoxy would shatter . Also I believe I read that Kevlar doesn’t take to epoxy so well. It doesn’t wet out so well. I read that someplace. I could be wrong.

[hughb]

I asked the same very question a while ago over whether to use kevlar or CF for inlay/reinforcement into a CF hull. The consensus was mixing the two materials was getting "the worst of both worlds". Plus with the apparent difficulties in working with kevlar (cutting, wetting out etc), in my humble opinion I'd stick with using CF. Also I've only ever used 3K CF, the 12K would be much harder to work and shape into corners where you need reinforcement, maybe just use several layers of 3K?

[boredom.is.me]

When working with both kevlar and carbon, you need to use real epoxy resin. Look for some marine grade stuff like West Systems or System Three. Anyone complaining about wetting probably tried using vinyl ester, polyester, or some 5-30min resin in a tube, none of which can even bond to the two fabrics.

The worst of both worst is also a weird idea. When mixing paint colors, you mix whatever until you achieve the desired end result. If you need stiff, you use pure carbon. If you need flexible, you use kevlar. If you need stiff with a little bit of give to it, you use both. It's that simple. Also don't count out fiberglass. It's actually the strongest of the three. When either of the three are used properly, you get the result you want.

[dmitry100]

I just wonder where this sort of flexibility would even be needed in a hull where absolute strength is needed. My HPR 99 ultimate hull seems to use Kevlar as the first layer after the gel coat (or whatever it is) from what I could tell. Since my gel coat had some bubbles which I filled in recently.

Though I intend to strengthen my radtek mystic 45” — now that I think of it maybe it doesn’t need as much reinforcing as I thought as I think a lot of fiberglass is used instead of carbon — it weighs about 7 pounds total with cover. The cover alone is almost 1 lb.