Sea Sled madness. It’s in my brain.

The bottom of the gutter is ⅜plywood. Over an 8½" span. It will be glassed, but nothing is supposed to touch that thinner plywood except water.

 

No. I mean the hull bottom.

Anytime you introduce a weakness to a hull, offsetting it must be considered.

Perhaps AH wanted the long Ts because of those two big holes across from each other.

I'm just trying to remember your hull laminates.

 

Ah, ok. ⅝planking, 2-5 layers of 17oz biax outside. 2-3 layers o3 14oz inside. And of course that region has 5x the framing recommended in Elements of Boat Strength.

 

I am not smart enough to know what happens when you put a big hole in the boat on each side, but the basic physics would suggest that area is weaker. I realize your gutter is added strength, but I think I'd add some glass around the cutouts on the inside or a long T under the gutter at least. If nothing else, peace of mind. If something, to prevent any stress cracking around the water exits. If something big; to prevent a massive crack event.

Also, think you ought to reconsider the long Ts if you plan to load the forward cockpit heavily. I am worried you will be stronger above than on the bottom and using AH words, possibly accordion.

It isn't about weakness, per se, but about weaker vs stronger. I can't see the gunwhales breaking, but if you try to break the boat there, where would it break..?

 

I do think about the holes as well. But the existing structures on all 4 edges should be sufficient. At the front edge there's the 2x4 frame, at the back edge there's the full bulkhead, the upper edge has the cockpit sole,and the lower edge has the gutter bottom.

As far as longitudinal strength goes, there's the hull, as well as the absurdly heavy side decks, but also the sole as well. The compression strength of the glass/plywood/glass laminate sole is on the order of 10000 psi, provided it's fully constrained. And in the cockpit, with a full bulkhead every 11", it is completely prevented from deforming out of plane under any load Serenity might conceivably experience.

 

Still, ask yourself where it would break. It is a good exercise, because you WILL think about it in heavy seas.

 

Soon I'll be painting. Fairing to @fallguy standards will have to wait. I reckon some behr porch and stair paint from Home Depot will keep the UV off for a few years.

 

Well, I phoned my mom, got my balls out of her purse, and cut holes in the hull. So anxious about cutting my baby that I totally forgot to round the corners.

 

Just smooth out the beari g surface and run a router over it. Hard on the bit; use an old one. ...called ur Mom.. lol

that hole doesn't look that big

 

No, it doesn't. 38 square inches each. It's what Ad Hoc's formula yielded. I could just keep making it bigger, but at some point I need to trust the NA.

 

That looks pretty low down ? How far up is it ?

 

19", 48cm above the keel. Tape measure's a bit out of focus.

 

Really ? that is somewhat lower than what your transom ledge would be with XL motors. Hope it is OK

 

Me too. A couple folks have suggested a turned out lower and leading edge, so the ports aren't constantly ingesting waves. Sounds reasonable.

 

It does sound reasonable