And So it begins

[Wildman]

I disagree with Bushwacker. Your this deep, rip that sucker outa there and replace it with new material. You are this deep, might as well do it all. I shaped up a 2X6 piece of lumber to match the original. Mixed up a couple quarts of cabosil to take up the grinding nicks and voids below it, made some nice smooth 45deg fillets on the sides, and then glassed the heck out of it with 6in 1708 tape.

When they popped these hulls out of the mold they drilled 1/2in holes thru the center stringer to grab it, then never sealed them back up. My keel stringer was actually cracked at one of those holes. Also when they rot they DO allow the hull to flex then the hull will crack right beside the stringer. Ask me how I know... this is what sunk my Mako 2 years ago.

[DonV]

Hey Patrick, a Mako versus SeaCraft is not a fair fight!! Actually a SeaCraft to most any other boat is not a good comparison. After I drilled the 3 3/4" hole in my hull to install the transducer, just for grins, I checked the thickness of the glass with digital calipers, it's a smooth 0.415 inches. The closer to the keel it's even thicker.

I remember when my brother had to take his 21' Wellcraft back to have the hull replaced, the hull was just at 0.200 inches....real, real thin. It's scary coming in with water coming through cracks in the hull!!

[Bushwacker]

Interesting info on the Mako! Drilling a 1/2" hole through the glass of the keel stringer would weaken it considerably and possibly create enough of a local stress concentration around the hole to cause cracks or delamination around it and down the sides of the stringer. However, that doesn't mean that's how they pulled the SeaCraft hulls from the mold, although maybe it might apply to the Tracker models. I believe Strick and others have found evidence of a loop built into the laminate up in the bow area of the 20' hull that was used to attach lines/cables for pulling the boats out of the mold. There appears to be some tumblehome built into the transom of the 20, so it makes sense that to pull that hull from the mold, you would have to pull it up and forward at the bow; probably could not remove it by lifting straight up at the transom.

Can't disagree with the advice to rip out and redo the keel stringer if you want to do extra work, but I question the need to rebuild it heavier than the original. Moesly used spruce stringers in the 21 before he started using hollow fiberglass stringers, and I remember Skip telling me that Carl said it really didn't matter if the wood rotted out because it was the glass wrapped over the stringers that provided the strength. That's a fact that's pretty easy to prove by comparing the bending stress calculations for a solid vs. hollow beam.

[alexh]

Originally Posted by Bushwacker

a loop built into the laminate up in the bow area

My 89 18sf had these fiberglass loops located on the outboard side of the stringers maybe 2/3 of the way fwd from the stern.

[Wildman]

The 1972 mako and 1972 SC 23 had a almost UN-noticable difference in hull thickness in stock form which really surprised me. (I had drilled thru both hulls at one point sitting side by side) The half inch holes were definitely there from the factory, as the deck had never been pulled up and the areas where they were located were not accessible with the deck in. (under the tank platform) Seeing as how this is a very early boat, they could have changed the practice over time and used 'glass straps' instead.

Do not misunderstand me, I do NOT think the damage that the Mako sustained would ever be possible on a SC, because of the fiberglass boxed stringers. BUT anything is possible. This is a VERY VERY common problem with older Makos, because of the wooden stringers.

[martin]

Nothing like the smell an feel of fiberglass in the morning

[martin]

Today I started to remove the Transome core. Man what a mess. I made sure the transom was over the Trailer bunks before removing the core. I cut about 5-6 inches back from the transom across the stringers and removed the foam core . and then cut the perimeter around the transom. I then used block wedeges and pry bar to remove the plywood core.. The outer skin is very thin so I had to be careful not to damage it.. Like 0.125 thick. I never thought it was going to be that thin.. I did see about 0.0.25-0.375" thick of cabisil to bead the plywood. to the outer skin and then about 0.25 on the inside

[martin]

here are the pictures

[martin]

I then Pressure washe and degreased the whole entire hull. drilled relief holes for the water to weep out of voids in the glass and foma.. Then Decided to cut out keel...

[martin]

Now I have to wait and let the hull dry out. I tarped the whole boat nad let dry for a few weeks