Blueprinting hull and making it smooth and straight

[rgsauger]

Hi fellows,
So the bottom of my Shadow mod-V hull has seen better days. There are some gouges and scrapes here and there. If I flip it over and break out the long straight edge, what material do I use to fill low spots and gouges and such? Thickened resin with Cabosil in it or….? High build something or other? Bondo?

I rebuilt everything except the bottom running surface when I tore it all down. Kinda sorta ran out of patience and wanted to get on the water. Lol

thanks

[LakeFever]

What top coat are you going to use?

[rgsauger]

Not there yet in my head. Gel coat? Paint?

[LakeFever]

The reason i ask is if you use gel you have to consider puttys that are poly based to properly gel over them. If your using paint the door is wide open to use whatever. The poly fillers are great but tend to pinhole pretty bad making final prep a pita. Epoxy putty’s dont have this issue but you cant gel over them. You can spray duratec vinylester primer over epoxy and then gel over that but the costs start to really climb. Another option and one seriously worth considering is using vinylester resin with bubbles and make your own faring putty. Great bond and 100% water proof and can gel directly over. Its also cost friendly

If your gonna paint it with awlgrip or similar you can use whatever putty you like just be careful not to go too thick with putty it can crack

[Tomanytoys]

We used epoxy thickened with cabosil to blueprint the bottom of my sons 15R and put a lip on the pad.
It worked great.
To finish we used rattle can grey high build primer…….easy to apply, easy to change and easy to maintain / repair / reapply.

[rgsauger]

When folks talk about straight bottoms and square crisp edges, how much difference on handling does it make before and after?

[DangerNewb]

When folks talk about straight bottoms and square crisp edges, how much difference on handling does it make before and after?

Depends on how far from straight it is. I just had the bottom fixed on my 2022 Liberator. $2,500 worth. One side had so much hook in it, the shop used 3 layers of glass to fix it. The other side was fixed with faring compound. The boat was impossible to get past mid 90's without major porpoise/hop if the water was smooth. Was ok on a decent chop, but absolutely impossible on smooth water. Runs like it should have all along now that I had it fixed.

[DangerNewb]

Pic of the hook and pic of the repair in process. The hook was about 3/16 inch in about a 10 inch span. Just in front of transom.

[powerabout]

Dont forget about the inside, it has to be strong to remain straight at speed

[LakeFever]

Heres a pic of my pad after blueprinting. I used kitty hair fiberglass to shape, then polyester fairing putty. Cut it down with durablock sanding blocks, mostly the 30” one. We cut it down flat with 40grit and finished it in 80grit before priming with duratec. Then we gel’d and that was a disaster then we sanded the gel down starting with 180grit, then 240grit, then painted it with endura epoxy. ( similar to imron, awlgrip etc )

[tnelsmn]

Adtech P-14 works pretty well for blueprinting the bottom. Bondo brand uses talc which will absorb water, stay away from that. Here's a few shots of mine after doing the bottom.

I also added one where I used the Adtech to touch up a corner that I bounced off a boat ramp, no paint or anything afterwords, just left it as is. Still holding up after two seasons.

[rgsauger]

The work you guys have done of your pads is absolutely amazing. I have never seen something so smooth and flat. Mine is nowhere even close to being in the same class. Gives me encouragement that there’s definitely room for improvement. Thanks for sharing pictures. Those are great.

[LakeFever]

Its not hard to do it just takes time. Coat, cut, repeat until your pleased with it. The only area thats tricky is the sides of the pad. Have to watch you dont mishape it or cut lines into the hull with the other edge of the sanding block. I ground a radius into a block to match the radius of the pad/hull transition.

Im not sure how fancy you want to get of your looking at good as new type thing or just going for fast fix and function. If fast fix and function are your goals vinylester and bubbles to make your own putty is 100% water proof and rattle can over it for looks. Could probably wrap the whole job up in a day or two

[rjdubiel]

Adtech P-14 works pretty well for blueprinting the bottom. Bondo brand uses talc which will absorb water, stay away from that. Here's a few shots of mine after doing the bottom.

I also added one where I used the Adtech to touch up a corner that I bounced off a boat ramp, no paint or anything afterwords, just left it as is. Still holding up after two seasons.

I used AdTech P-17 black per the suggestion of the crew at Express Composites. It can be buffed to a gloss and does come in white and gray also. I had a small hook after the core was bagged down.

[Jim Speros]

Some nice work people have shared. If all your doing is repairing nicks and void pops white Marine tex works well. Easy to use and can be buffed. May not make a perfect match of color but works well.

The faster the boat goes the more important a true bottom matters. 60 mph you may not notice much of an improvement. At 100 small improvements can be noticeable.