1988 16' Radoncraft Hull Repair

Greetings. First post here, but I've spent quite a bit of time reading through some of the various restoration projects. The last time I lifted my boat out of the water I noticed a crack in the hull that appeared to be deflecting outwards, not inwards, like it would have if I had hit something. I got the boat home and went after the crack with a grinder. After grinding through the hull, there was another section of fiberglass that was creating a hard point that the hull was flexing against and caused the crack.

It wasn't easy to get to the hole from above, so I had to do some removal in the bow storage compartments to get access to the hole. I found the hard point, but in the process I also found out a bit more about how the boat was constructed.

It turns out they used an upper liner than consisted of a fiberglass skin and the stringers. This was then glued to the hull to make a sort of composite hull. There is between 1/8" and 1/4" between the hull and liner and it looks like the adhesive used is delaminating from the liner and stringers. The stringers don't appear to be rotten, but when I cut into the liner, quite a bit of water was present between the two fiberglass skins.

Here's a shot of my boat. It's a modest 16' center console.


This is the layout of the bow area:


Here's a few shots of the starboard storage compartment

Re: 1988 16' Radoncraft Hull Repair

Here's where the crack was after I ground it out and you can see the fiberglass hard point above it


After reading through this site quite a bit, I've come up with the proposed repair schematic and wanted to run a couple questions by folks here. I plan on removing the fiberglass skin in each bow compartment and then running a fillet between the stringers and hull, then laying new glass down. The existing stringers sound solid, and I'm not seeing any signs of rotting (at least not yet).


Now, the questions:

1) I talked to a local boat repair guy and he recommended vinyl ester resin or epoxy resin. I'm not going to use epoxy, as I'm planning on gel coating over the repair (either rolling, or spraying with webbing) and I'm wondering if polyester resin would be sufficient, or if I should go with vinyl ester resin because of it's stronger bonding capabilities. My biggest concerns is the glass that will be layed up against the existing hull fiberglass. I'd hate to go through this work and then have the new glass delaminate from the old.

2) I'm a little concerned about adding too much weight, so I went with one layer of 1708 sandwiched between two layers of 1.5 oz csm. Will this be sufficient, or should I add a layer of 1708 & csm to the schedule?

3) I've read that for peanut butter used for fillets that a mixture of resin, chopped strand, and cabosil works well. However, I found a product guide put out by tap plastics and they indicated that chopped strand shouldn't be used for fillets. I can't see any reason not to use chopped strand in the fillets. Thoughts?

4) Any other input on the repair approach would be helpful. I've done minor glass work before, but this is the biggest job I've tackled to date.

One final note - I have access to the stringers in the stearn of the boat and so far, based on sounding them, they sound solid.

Thx in advance,

Matt

Re: 1988 16' Radoncraft Hull Repair

repair with a kevlar reinforced epoxy putty (like Wet Dry 700) and fiberglass cloth as needed. You can use the fiberglass cloth with the wet dry 700

Paul Oman - MS. MBA
A.K.A. “Professor E. Poxy”
Internet Epoxy Confederation (IEC) Homepage
epoxies since 1994
Member: NACE (National Assoc. of Corrosion Engineers) -- SSPC (Soc. of Protective Coatings)

Re: 1988 16' Radoncraft Hull Repair

Dude, Radoncraft hulls are so awesome, nice riding in the ocean. I fish on a Davis Rock Harbor 25 and it uses the Radon mold. Good luck on the repair. You might see if Radon's son in Oregon might have some suggestions, or even Harold Davis of Davis boats. I don't know how to get hold of Radon, but Davis should be reachable on the Davis Boats website.

The Davis 25 hull is constructed the same way. Is there foam between the skins? Even the cabin is constructed that way.

Re: 1988 16' Radoncraft Hull Repair

Sea Stomper said:

Dude, Radoncraft hulls are so awesome, nice riding in the ocean. I fish on a Davis Rock Harbor 25 and it uses the Radon mold. Good luck on the repair. You might see if Radon's son in Oregon might have some suggestions, or even Harold Davis of Davis boats. I don't know how to get hold of Radon, but Davis should be reachable on the Davis Boats website.

The Davis 25 hull is constructed the same way. Is there foam between the skins? Even the cabin is constructed that way.

Click to expand...

Sea Stomper - I love my hull - it does pound a bit going up hill, but a guy once told me to solve that by going 'slow like a pro'. Coming down hill with the thing is a pure joy.

So, when I first got the boat 5 years ago I reached out to Don Radon out of Santa Barbara to find a bit about the history of the boat and his comment was 'I didn't build that boat' and he pretty much left it at that, which I can understand. His involvement with Radoncraft is documented a bit here: Radon Boats - History

I ended up giving Harold Davis a call last week and he didn't start making the Radoncraft boats until sometime in '91. My boat is an '89, I believe. There were quite a few different builders of Radoncraft boats and Harold said some of them were even built out of Mexico. There is also a line of boats called a Bahia that is nearly identical to the Radoncrafts.

While describing the issue I was having to Harold, he seemed to think my boat may have actually been a prototype. Part of this was because I described the bow storage compartments/fish holds as having a gel coat w/webbing finish. He said it definitely wasn't one of his because all of his compartments up front came out of a mold. He also had a larger gap between the fish holds and the hull than my boat does.

To answer your question, there is not foam between the skins in the bow of the boat. There are the two skins, and then adhesive between them. In the back of the boat, they did use more of a standard foam sandwich/composite construction technique. I cut into the back in the bilge area because I was pretty sure I had some water trapped between the two skins and wanted to drain it out. You can see the sandwich construction in the photos below. I'm going to remove the upper skin and foam from the bilge and put some new glass in here, as well.