Sea Ox Rebuild

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
Dipper
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Re: Sea Ox Rebuild

Post by Dipper »

Clarification: On the outside of the outer skin i will only be glassing a section in the middle just wider than the tunnel. Not trying to lay glass across the whole back.

fallguy1000
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Re: Sea Ox Rebuild

Post by fallguy1000 »

Do NOT try to table wet that! It will all end up in piles.

DB1700 is best dry fit, minimum overlap is 1"; 7 pieces is too many and will start to smoke done too quickly.

The way to do it is drystack all of them, longest largest
First. Use as few pieces of clean release masking tape as possible. Dart and cut as needed to prevent corners building. Use sharpies to draw overlaps and label them well. Which side is up, which piece is 1-7, etc. more marks are better than none; jist avoid using red sharpies; draw lines on the boat where the biggest piece goes; then draw lines on each next piece at less 1" or so overlaps. A 12" overlap on each side and each piece 1" smaller would be like 4-5" overlaps of hull sides on edges. You can achieve same results with about 5 layers of glass if you turn each one 15 degrees..

Then when you have them all dry fit; lay them out biggest first. Wetout the boat and roll the piece on dry. Wetout each piece in situ. After the piece is on; consolidate and remove bubbles. Then using a paint roller, wetout again with about 50% of the resin needed for each piece.

7 is really an awful lot and you would need to really go slow to avoid a bad heat reaction...

I can offer more help if you have any questions. My boat got 4 layers on each side of the same glass and wrapped over the top in separate days; for 8 total layers. A lot of strength is developed overlapping transom top..this would mean for you removing all paint/gc and refairing transom, but you could avoid hull and hullsdes fairing.
My boat build is here -------->

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fallguy1000
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Re: Sea Ox Rebuild

Post by fallguy1000 »

If you want to do 7 layers, I'd say no more than 3 layers hour one, two layers hour two and last two layers hour three. Any faster and you'll have trouble where corners build and overlap. I'd personally go for 4 hours.
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goingbogueoutdoors
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Re: Sea Ox Rebuild

Post by goingbogueoutdoors »

Here’s a photo of that Sea Ox with same tunnel installed. Trim tabs were an important addition with the setback his jackplate has:
0E004D9C-9897-43FF-AED2-7D72748FE7F0.jpeg

fallguy1000
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Re: Sea Ox Rebuild

Post by fallguy1000 »

It isn't a lot of tunnel. I still have a few open questions about it. Perhaps it is working well because it isn't doing all it can. Typically, for example, a tunnel is designed to compress the flow as well. This could be achieved by tabbing, I suppose, the outside end to the transom. I'm not smart enough to do a major critique, so if it works; go for it. Sometimes, tunnel designs are horrid and too large. I was mostly concerned this was a bit small, which is a safer error.
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goingbogueoutdoors
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Re: Sea Ox Rebuild

Post by goingbogueoutdoors »

fallguy1000 wrote: Tue Feb 15, 2022 9:35 am It isn't a lot of tunnel. I still have a few open questions about it. Perhaps it is working well because it isn't doing all it can. Typically, for example, a tunnel is designed to compress the flow as well. This could be achieved by tabbing, I suppose, the outside end to the transom. I'm not smart enough to do a major critique, so if it works; go for it. Sometimes, tunnel designs are horrid and too large. I was mostly concerned this was a bit small, which is a safer error.
I understand. It doesn’t seem like much but it is a very prominent design and is seen on a multitude of boats around these parts. Larger deeper tunnels tend to rob a lot more performance than these ones do.

General consensus from the shallow water skiffs here are mainly two kinds of skimmers. Skimmer as in a skiff with a flat bottom. The first is to have a skimmer with no tunnel, but jack plate offset. The second is to run a tunnel, but without the jack plate. Usually the offset provided by the jack plate will disrupt the hydrodynamics of the lower unit being able to utilize the flow of the tunnel and will further the poor performance characteristics.

With the shallow V hulls like sea ox, privateer, c hawks, etc the woody hancock style tunnel with jackplate seems to be the most versatile option to be able to reap the benefits of both.

Fuzz
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Re: Sea Ox Rebuild

Post by Fuzz »

Re tunnel...........I learn something new every day :D
You are going to have a nice boat when finished.

Dipper
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Re: Sea Ox Rebuild

Post by Dipper »

Thats a good looking Ox! I think its really a balance between being able to run shallow and still being able to take rough water. You dont find many v hulls with tunnels because the two concepts are kind of counter intuitive. It certainly isnt operating like a true tunnel but improves shallow capability just enough to be very functional in our waters.

Hoping to get the transom in by the end of the weekend. We'll see how it goes. Largely depends on cure time of the outer skin. We've had cooler nights here and Im using slow hardner so some layups have taken a good while to fully cure.

fallguy1000
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Re: Sea Ox Rebuild

Post by fallguy1000 »

So, all that is there is the exterior fiberglass, correct?

And the other side is gelcoat?

And the thickness is 1/4"?
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fallguy1000
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Re: Sea Ox Rebuild

Post by fallguy1000 »

The best way to do the skin repair ...

I would taper grind for 1/4" skin thickness back 3" all around. Use 40-60 grit and not smoother.

Install some type of backer that takes up 0.050" of the existing space. This is to allow a final piece on the outside. More if you need to gelcoat match...gorilla ship tape or a sacrificial piece of fiberglass with wax could work..etc

Lay in the smallest piece of 1708 first for a total of four. It will bump the edges only or tad short. Each of the next three pieces one inch bigger. You will want to add a wee bit of thickened epoxy on edges as you go. It doesn't have to be perfect fill; the consolidation will help lay it down as hard to do on wet glass..etc. Fourth layer is to edge of scarf.

After it cures; remove the takeup piece and grind the outside for about one inch; remove gelcoat and grind for 0.050" plus 00.020" for gelcoat; then install a piece glass on the outside.

Basically this is just a skin repair, but if you butt seam; it'll crack over time.

Then you add transom core.

Make sure you bond the tunnel again with tabbing to the inside of the transom core. Bonding it to the skin was really not a 'structural' bond, if you will.

Sorry for my confusion. I thought you were going over a core already..

i strongly recommend using 1708 here. It will table wet and not misshapen and you roll it onto a cardboard tube and carry to the boat. And it is thicker so you can do it all without heat worries. 1700 is snaky and harder to use. In a pinch; 1700 can be wetout on plastic and the plastic can be carried to the repair, but gives me nightmares and I am very experienced...the 1708 can be applied in reverse and with poly on the outside one inch overlap piece for gelcoat as well
My boat build is here -------->

viewtopic.php?f=12&t=62495

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