GF16 questions.

Power Boats only. Please include the boat type in your question.
matth6
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Re: GF16 questions.

Post by matth6 »

Reid,
This makes perfect sense! I had not thought of having to repair them and understand why they would not be glassed in. Thanks for the insight and tips!







Reid wrote: Thu Apr 28, 2022 2:44 pm matth6,

There are a few conflicting opinions on the application of spray rails/runners/skegs and I'm sure you will hear several shortly.
Personally I like to install these parts after the boat has been faired, prior to primer. I don't like to attach these with fiberglass, simply prep the site well and epoxy glue them on. The reason being (and this may be more crucial to skegs on the bottom of the hull), if you were to make an error and hit something, rub a piling, run over a sandbar or oyster bed, or hit something below the waterline, the skeg/rail would be sacrificial and hopefully come off without doing any damage to the integrity of the hull. You can always go back and make a new skeg/rail easy enough.

Fairing is not a complicated process. Mixing microballoons into your epoxy is easy enough. It may take a few tries to get your technique right.
That being said, the System Three Quick Fair is a really nice product that has taken a lot of the guess work out of mixing up a fairing compound. It is also very easy to spread and (probably the best attribute) it is easy to sand. The down side, it costs a little more.
A good compromise is to do the initial fairing with microballoons and then switch over to Quick Fair to dial in the hull.

Hope this helps!
-Reid

Noles309
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Re: GF16 questions.

Post by Noles309 »

I glassed over the runners on my gf16
Gary
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piperdown
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Re: GF16 questions.

Post by piperdown »

Noles309 wrote: Thu Apr 28, 2022 3:42 pm I glassed over the runners on my gf16
Glassed over my runners too.
Not sure if I'll glass the splash rails when I get around to finishing it up.
Eric (aka, piperdown)

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matth6
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Re: GF16 questions.

Post by matth6 »

How many people (if any) do an extra layer of glass on the bottom of the hull of this boat?. Are there any disadvantages to this other than cost and additional weight? I’ll be fishing mainly texas gulf coast bays and back waters and the thought of a single layer of glass between the plywood and the potential of an oyster bed makes me think an extra layer might be beneficial. Before I do something irreversible I thought I’d ask the fine folks here. Thanks for the advice.

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Re: GF16 questions.

Post by OneWayTraffic »

I know Cracker Larry put the second layer on for that reason. If I was really worried about such I'd put UHMWPE on the bottom. Screwed and glued. Jetboaters do that to run NZ rivers in Canterbury. These rivers are always a gravel/rock bed and shallow. Hitting bottom comes with the program.

matth6
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Re: GF16 questions.

Post by matth6 »

OneWayTraffic wrote: Sat Aug 13, 2022 6:40 pm I know Cracker Larry put the second layer on for that reason. If I was really worried about such I'd put UHMWPE on the bottom. Screwed and glued. Jetboaters do that to run NZ rivers in Canterbury. These rivers are always a gravel/rock bed and shallow. Hitting bottom comes with the program.
I was toying with the idea of ( second layer of glass or not) glassing in the wood runners and screwing plus glue a uhmw layer to the runners. Does marine epoxy bond to uhmw?

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Re: GF16 questions.

Post by OneWayTraffic »

People will tell you no. It can be, at least if you go to some extremes or use a UHMWPE specific glue.

I glued mine on with WEST G-Flex after flame treating. This needs to be done with a propane torch on clean plastic over the entire surface. You can check it with a water break test to see how the water no longer beads off.

viewtopic.php?t=64694&hilit=UHMWPE&start=170
Some will say that this can’t be glued at all. Well apparently it can. The plastic has very long chain molecules that don’t strongly interact so the surface needs to be modified. First I wiped with acetone to remove dust. Then sanded with 60 grit. This was a very quick sand. Then acetone again and on to the propane torch. Kissing the surface with a quick pass of the torch (about 30cm a sec) propels reactive atoms (single oxygen and others) which are supposed to break up some of the long chains and also replace some hydrogen atoms with oxygen which can electron bond to the glue molecules. The treatments max effect is supposed to last about 15 minutes so you need to get the glue on fast afterwards. Then I screwed this into the chine like before. The screws will stay as insurance, though the glue is supposed to bond with over 2000psi to HDPE with good treatment. I have a couple of small samples: one just sanded and acetone wiped and one fully treated with wipe-sand-wipe-flame. I’ll test when fully cured. It would have been easier to go with hardwood, but I'm hoping this will be stronger and longer lasting.
I actually removed the screws and plugged the holes. If on the bottom of the boat I'd be tempted just to use tape to hold it in place. Do experiment first.

On the page I linked to there's a photo of a test where the plywood failed internally before the glue gave. I also screwed up the keel UHMWPE strip and got that removed with a bit of effort. In a couple of places it pulled off a little glass despite use of a heatgun. Now I can grab one of the strips and yank it and the whole boat moves. Good enough for me.

It was a fair bit of research (which I enjoy), and a bit of work to get right. But I hope that the result will last a lifetime. Based on my experience I had a little bit of an easier time with the recycled UHMWPE than virgin. Make sure that it's been UV stabilised.

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Re: GF16 questions.

Post by OrangeQuest »

Just remember you are going to be running Gulf coast bays, not to many rocks or gravel to worry about in coastal waters. Concrete and oyster beds don't do the same damage as rocks and gravel that have been smoothed down from fast moving water. What speed will you be intentionally hitting these things? Take into consideration of what the boat will run over verses time, energy and expense on what you add to the bottom.
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
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TomW1
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Re: GF16 questions.

Post by TomW1 »

No need for HMWP two layers of tape over the runners is all CL did and he had lots of oyster beds in Savanaha to worry about. I fished with him on his GF16 and it was a really nice boat. Now on his OD18 he put a strip of aluminum on the skeg. Remember runners are considered sacrificial on small boats.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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Re: GF16 questions.

Post by TomW1 »

No need for HMWP two layers of tape over the runners is all CL did and he had lots of oyster beds in Savanaha to worry about. I fished with him on his GF16 and it was a really nice boat. Now on his OD18 he put a strip of aluminum on the skeg. Remember runners are considered sacrificial on small boats.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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