Shake down cruise. Hold on!

[linesider36]

The 86 20' MA hit the water with new bottom paint and at least 40 gal. of fuel and probably closer to 60 gal.I ran the boat without the anti syphon valve as whatever crap is still in the tank after polishing clogs that valve up tight. Yes i brought another spin on filter with me but didn't need it. Well the motor(93 175 Johnson) ran great. With the Sea Tow app for my phone my SOG was 40 MPH wide open. Don't know RPM as gauge can't be read but it was screaming. Way too fast for me. Tonight is the first night it's in the water and the problem is that the scuppers are about 2"-3" under water at the dock with no one in it so so much for washing it down. Stand on the dock and spray it and thats it, which sucks.. Well it runs anyway so now use it , enjoy it, catch some fish and worry about it. I'm guessing the 175 is too much for the boat so if i'm keeping it, I've got to down size the motor or rebuild the boat this winter or both.

[red20]

I have a 175 yamaha (1987) on my late 70's 20ma and dont get water on the floor when at the dock*

[FishStretcher]

I wonder if the later boats with plywood deck cores are even more sensitive to motor weight? My 1975 20MA has a dry deck with 425 lb on the transom. But I have forward tanks. When I got it, it had a 1988 175 yamaha and reportedly had dry decks with the batteries forward.

[flyingfrizzle]

Need to check to see if the stringer foam is wet, You may be carrying around an extra 500lbs of soggy foam. That hull shouldn't sit like that with a 175. I had a heaver motors on 20's with the older type 2" lower floor and it didn't come close to that. If there is some water trapped in there try drilling some escape holes in the bottom corners of the stringers and jack the boat up on a trailer and let it bake in the sun and drain out. The way they glass them in a lot of the water that gets in there can never get back out.

[linesider36]

Just got home from work so gonna go check that out.I painted the bottom this past weekend and followed the old waterline and now thats a few inches underwater. It sat uncovered for i don't know how many winters so it's definitly possible.

[FishStretcher]

Wet foam can be heavy, but at something like 8 lb per gallon, hiding 60 gallons of water to make 500 lb in the stringers if they already have foam in them might be a bit of a magic trick?

But wet plywood core in a deck might be 150ish lb more than a dry balsa core in a potter hull. That's guessing at 3 cubic feet of core in the deck. One at 64 lb per cubic foot, the other at 10.

[linesider36]

Fish, I'm pretty sure thats part of the problem. The decks are solid but the hatch over the gas tank is freakin heavy. Thats about 2.5'x5' and probably goes about 80-100 lbs. I'm off will keep you posted.

[uncleboo]

I did a little experiment when I put a 6" inspection plate over my fuel pick up line. The 6" round piece I cut out weighed 16 oz. when wet. let it dry for 2 months and re-weighed it to find it had lost 9 oz. of weight. Since the deck is wet and the transom is wet, I loosely calculated that I have approximately 180 to 190 lbs. of water weight in my 18. Unfortunately, I think the port stringer box has some water in it. I have about a 5 degree list to port sitting still and have balanced all the weight in it. ( Or it may be one of those pesky hog weights in there to offset the original battery placement!)

[jorgeinmiami]

I have a 77 MA and I pulled the gas hatch and it has to be at least 150 lbs took out the old water soaked wood and recorded with nidacore. ...now it weight is maybe 20-25 lbs. I also did the deck and I can imagine what kind of weight I took off

[linesider36]

I totally believe it! Flyingfrizzle thought that the stringers were holding water and they might but the boat sits level in the water at the dock, could they both be holding the same amount? I guess maybe. I'll take the hatch out of the boat and see how she rides. If all the decks are that heavy then I have a winter project.