I removed most of gelcoat in keel stub area under the existing floor frame and on the frame where it is directly over stub (about 75% was bare fiberglass), less under new plywood frame in stub. But most of gelcoat remains on the "upper" area of keel, still there are some spots that is bare fiberglass. Problem was that I did not want to grind into fiberglass too much and surface was so uneven that I would have to risk grinding too much solid fiberglass to get all the gelcoat removed. Also there are 2 school of thought about gelcoat, some say that it is fine to laminate over it since gelcoat technically is pigmented resin, unless original laminate is resin-poor. So I went for less risky plan. Besides with new plywood frame, if it delaminates, it will be useful as indicator that this area flexes more than it should.

For spraying I use cheap 25 euro air spray gun (regular gun, not HVLP), with 2.0 tip. (3 years ago I used 2.0 for primer and 1.4 for antifoul, but now I think 2.0 for both is better. Different antifoul tho, so might be just that too)
But for spraying bottom, gun needs to have some modification, because gravity feed does not work upside down. So you are going to need something like this: https://www.youtube.com/watch?v=8YwwLrXZLo8
Cheaper to get those cups from AliExpress tho (adapter is usually sold separately)

The frames didn't go all the way down in to the bilge on earlier Finn Expresses. I think it's good to laminate them all the way down. That said, gelcoat should be removed before laminating. Gelcoat isn't that strong, and any laminate laminated on top of gelcoat might just pop loose if grounding.

I do love the look of sprayed paint on the bottom. I have to try that myself now when I have the boat on my own yard. What kind of spraygun do You use, electric or air?

Now here is extra plywood floor laminated in
[img]https://img.eselt.de/img/15431885_MtHxAHYI7hwjXIcp/ad.jpg[/img]
and after painting:
[img]https://img.eselt.de/img/15431896_AudfNsjX83uIPCrF/ad.jpg[/img]

Last year, when we did bottom wash and cutlass joint was wet, I noticed that there was some minor flex (I saw the flexing thanks to water movement on joint). Easiest fix was to laminate it over, so i bough unidirectional carbon fiber for the job.
[attachment=4]20240420_123118.jpg[/attachment]

Also decided to strengthen bottom. One of floors did not go all the way down at bilge, but I think it should. So decided to fix it and add some extra strength using remaining UD carbon fiber cloth. I also plan to add plywood floor between the floor thats on top of the picture and keel bolt to add extra strenght. I will post when it is done.
[attachment=3]20240525_153341.jpg[/attachment]

Upgraded genoa cars: This has been in my mind for at least 5 years and now finally pulled the trigger. New cars are amazing, will back up under load when you release trim line: https://www.youtube.com/shorts/yOMne9SNd1g
On the negative side, new track bolts come through deck now. Must cover them up somehow or else might hit head against them.

New bottom job had to be done. My previous choice was Hempel Hard Racing Teccel, had it for 3 season. Last season it got bad. Decided to go with VC Offshore this time, and boy it was a good choice. It sprayed very smooth. (Tip: primer should be sanded with at least 240, since VC is so thin that scratches can be seen otherwise). After paint dried, it only needed very light wet sanding. I had a feeling that it sands better than Hard Racing, but not sure tho, since initial spray job was a lot better than with Hempel. I also had at least 2 low spots on hull, which i tried to fill, but did not get perfect, but better than before. Next time I apply new bottom paint, I might buy flexisander set and do it properly, but for now DIY fiberglass longboard and old sail batten for checking had to do.
[attachment=2]20240427_180425.jpg[/attachment]
[attachment=1]20240501_171631.jpg[/attachment]
Here is a situation of 3 season Hempel Hard Racing :lol:
[attachment=0]20231119_121508.jpg[/attachment]