Bass Relief- A Seafari 25 rehab

[Blue_Heron]

Originally Posted by FishStretcher

I have a goal of 50MPH, if not 50 knots. If chine walk doesn't get me first. But I need low, low slip numbers to get there. 3-4% Even with a bravo 3, it probably won't happen, but it is nice to dream.

If you hit 50 mph with a 350 Mag MPI and a Bravo III, I'm gonna go out and buy a Bravo III. I wish you luck, but I just don't think you'll get there. 25° deadrise = lots of wetted area = drag. But the faster you go, the more it will lift and reduce wetted area, so it's worth a try.

[FishStretcher]

It is a nice dream. I will try- I did a *little* prop design once, so I have some concept of things to try. But I think low 40s is more realistic.

[FishStretcher]

Worked on the tank hatch cover as much as my back would allow today.

For you Floridians- they call that white crap "snow".

[FishStretcher]

Hatch is done. LONG story. I found out that you can "B stage" vinylester (stop and restart cure with temperature), and that you can dry out 1708 with just peel ply, a LITTLE pressure and a week long cure.

I was glassing and the temp and humidity was rising. So I kept dropping the hardener. The last layer, I diluted the resin with ~10% styrene monomer and dropped the MEKP to the slowest cure (5cc/ qt). Then the ambient temp crashed and the humidity skyrocketed. The temperature dropped to 55F in 18 hours in my workspace, and over the week dropped below freezing. After a week I had resin that was between tacky and genuinely wet.

But Joe Merton mentioned that the vinylester will cure in sunlight to a degree, so I decided to finish the part in a solar oven consisting of two layers of poly drop cloth. I threw it on the back lawn. The UV and heat restarted the cure, and I wet out the slightly dry cloth with a bit more resin. Final cure/postcure temp was probably 140F. It was a learning experience where it was harder to work with the mat than the 1708.

Something unexpected- 1-1/2 oz mat is stiff until resin gets to it, so getting it in corners was actually harder than the 1708, at least in this case.

Also, no guarantees on resin strength, but that hatch probably has 2 layers of mat and 2 layers of 1708 topside, and half that on the under (bilge facing) side. It sure is stiff and kind of rings when you tap it. I am happy enough as a learning experience with the foam. Which was the easy part, this time.

[flyingfrizzle]

A lot of the time when it is cold outside and I cant do the work in my heated shop I will pre-heat the area with a hair dryer/heat gun and then once everything is laid I will heat the lambent slightly and once it starts to kick I found that the reaction of the vinyl-ester will produce enough heat to finish out the cure at its own natural rate. That's using 1%-3% mek. I don't like adding extra mek due to it getting brittle. But like you said a lot of the time the sun will provide all the heat you need to get it going. When I did my swim platform I laid it up in the shade and then carried the mold out into the sun to help it kick and soon as the sun started warming it started to cure out at a normal pace. Also sometimes I will turn the a/c on and cool off the shop to do all my lay ups and once Im finished I will switch to heat and bring it up to 85 degrees or so. That buys me more time to lay up everything and then get a good cure. I even cool the resin outside in thee cold and bring down the temp of it too but it gets thicker when I do that and makes it harder to absorb in to thick layers.

[FishStretcher]

Halfway thru.

Did I mention that my workspace is a rolled up tarp in a borrowed shed? Still waiting on my laminating table, A/C and compressor. Or electricity.

[FishStretcher]

I used 4 mil poly to trace the existing bulkheads. These are rough oversize cuts in 3/4" H80 divinycel. I need to trim at least 3/4" all around for the trapezoidal spacer. I hope to glass them this weekend. And maybe glass them in place next week.

I am going to pull the under cockpit bulkhead first, despite my worries about hooking the hull.

I will try to put CSM on both sides simultaneously, fiberglass (raptor) stapled down, let that kick, then lay down the 1708.

And yes, those ARE brass tacks.

[FishStretcher]

I laminated the bulkheads this weekend. One with 1.5 oz CSM, then 2 layers of biax. The other with 2 layers of 1708 double bias (stitch)mat.

I did the latter all at once. Slow vinylester layup. 0.7% MEKP and 60F outside. I used peel ply, then covered with 2 mil polyethylene sheet. Then I flipped it and did the other side. That worked pretty well. The first one with the separate inner layer of 1.5 oz CSM isn't quote as pretty, and at 65F and 1.2% MEKP warped a little. Oh well.

If I did it one more time, I would use one inner layer of 1708DBM, an outer of biax (no mat). Pretty happy with the results. The 1708DBM panel is pretty light and very stiff, and I hope strong. The first with the separate mat is a little heavy.

[FishStretcher]

The bulkheads still have peel ply on them and need trimming to final size, but they are WAY WAY stiffer than equivalent thickness ply. And lighter. Totally worth the work. I finished the under deck stiffener tonight, too. More pictures this weekend.

[FishStretcher]

Demoing the under cockpit bulkhead. That was a lot of work! I wish I hadn't repaired the tabbing last year with vinylester. It would have come out a lot easier that way. More grinding tomorrow, then sandblasting, then trimming the foamcore bulkhead to fit, then maybe fiberglassing, if time permits.

$58 harbor freight sandblaster with pressure feed. Going to take off a few layers of paint and gel coat in the corners of the hull before I glass everything in.