1979 19 ft Sea Ox rebuild

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
Fuzz
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Re: 1979 19 ft Sea Ox rebuild

Post by Fuzz »

If I was doing it I would glass them to the stringers. I feel like the force would be better transferred to the strongest part of the boat. Glassing to the deck might be just as strong but for me I do not like the "might be" part.

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cape man
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Re: 1979 19 ft Sea Ox rebuild

Post by cape man »

On most of the designs here there is a splash well and space for two hatches on each side that form a "box" which is tied to the transom, floor, stringers, and sides with the bulkhead running all the way from the hull to the top forming the front face. This box transfers the energy in several directions, but with a focus to the stringers. It will be more than knees to walk around so you may have to use a smaller leaning post or move it forward. Given that you are pretty much going from scratch, you can also make the box narrower than the standard spacing Jacque uses.

I love the wide open deck you have now, but I would worry about the transom being able to handle the force of a set back 115 on it's own. I am not a marine designer, so take this only as a comment, not the truth.
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Mr Pamlico
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Re: 1979 19 ft Sea Ox rebuild

Post by Mr Pamlico »

So when connecting the knees to the transom should I glue them to the top of the stringers and to the transom or glue them to the side of the stringer and to the transom? I’m not sure the best way. If I glue them to the top then I could glass on either side from the knee down to the stringer. If I glue to the side I could run the knee further down the stringer and I feel like once glued would have more contact area. Just not sure how I would glass to the stringer after that approach. Boxing that in would make it easier for rigging and wash down pumps and such. I’ll have to see how much room that would take up

fallguy1000
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Re: 1979 19 ft Sea Ox rebuild

Post by fallguy1000 »

I'd say either or... the piece on top not as strong, but lighter..
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cape man
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Re: 1979 19 ft Sea Ox rebuild

Post by cape man »

I need to correct my post. The "box" is not tied directly to the stringers. The sole on my OD18 goes all the way to the transom with a cut out for a small bilge area in the center below the splash well. The splash well and the two hatches are glued and taped to the sole, transom, and sides. There is not a bulkhead going all the way to the hull and stringers and the top of the structure. However, I still stand by the concept that it creates a "box" that transfers energy from the transom uniformly, and stiffens the transom.

Sorry for the misinformation.
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fallguy1000
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Re: 1979 19 ft Sea Ox rebuild

Post by fallguy1000 »

Honestly, I think a bulkhead full height to the hull would be wise. It does not need to be coosa, but can be. It can be made from light foam or offcuts if you laminate it with db1700 both sides on the table.

Move it in enough for the motor to tilt all the way up.

Build the knees right on top of the existing stringers with an angle.

And build a splashwell.

This is the strongest.

I have seen people build a box, but I think a bulkhead across is a better way to transfer forces to the hull. Spaces beneath are nice stowage for a stern anchor or start batteries and the space between the knees can be used for a sump, pump or drain.

I am not sure you will be strong enough without the bulkhead. The bulkhead also increases your transom to full height and gives you a safety margin from breaking sea.

If you don't like the spaces lost, you might be able to cut in benches on each side. This would be flat topping or modifying the height on each side for a seat. Still a lot of force transfer and you get seating. Not sure, looks quite low now..etc.

You can install the sole after the bulkhead is in..

My 3 cents.

fallguy1000
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Re: 1979 19 ft Sea Ox rebuild

Post by fallguy1000 »

Honestly, I think a bulkhead full height to the hull would be wise. It does not need to be coosa, but can be. It can be made from offcuts if you laminate it with db1700 both sides.

Cut it in enough for the motor to tilt all the way up.

Build the knees right on top of the existing stringers with an angle.

And build a splashwell.

This is the strongest.

I have seen people build a box, but I think a bulkhead across is a better way to transfer forces to the hull. Spaces beneath are nice stowage for a stern anchor or start batteries and the space between the knees can be used for a sump, pump or drain.

I am not sure you will be strong enough without the bulkhead. The bulkhead also increases your transom to full height and gives you a safety margin from breaking sea.
My boat build is here -------->

viewtopic.php?f=12&t=62495

Mr Pamlico
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Re: 1979 19 ft Sea Ox rebuild

Post by Mr Pamlico »

I did not account for having to build a splashwell in my plans. My original thought, or I guess I should say assumption, was that if I built the transom to 2 inches thick it would be strong enough for the 115 and then a 3/4 or 1 1/2 inch coosa knee on either side of the engine would add extra strength for the jack plate. I was hoping to keep the same layout the boat had as it fit my needs as best it could for the size boat it is. With the tank I have and where it is going and where my console with live well has to be placed to still have access to the fuel fill, sending unit and pickup if I build that bulkhead and splashwell you would not be able to walk around the back of the lean post. As it is now there will be enough room for one person to sit behind the lean post on a bucket to hunt, walk behind the lean post while fighting a fish, or have some room to walk side to side to throw a shrimp net. All of which are the main uses for the boat. I would have to change the fuel tank, console or redesign the stringers to accommodate moving this tank further back and the console forward. I would really like to be able to keep all the room/floor space possible as I used the boats full deck and then some as it was, if there is another route that would make it strong enough. I still haven't closed in the top of the transom so could I do some extra layers there to add some strength? Also what about this brace idea?

I would add this 3/4 coosa piece first and glass it to the stringers and tab to the transom

Image

Then I could come back and sandwich that piece on either side with 3/4 coosa that runs down the stringers. Glue and glass that to the stringers and tab to the transom on either side. Then round of the edges and glass those three pieces together

Image

Image

I also was planning on building diagonal boxes that followed the same lines as the top cap in the back corners to run the rigging up on one side and to put the washdown pump on the other. I was going to follow those lines and keep them as tucked in as possible to not take up floor space. If they are tabbed to the hull side, sole and transom would that add to the strength as well? I understand the reasons that the bulkhead and box design would be the strongest but I know that I would not be happy with that in the back of the boat as a finished product. Would any of these other ways, or anything else, be able to get me to the strength I need?

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Re: 1979 19 ft Sea Ox rebuild

Post by fallguy1000 »

Where's the start battery going?
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Fuzz
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Re: 1979 19 ft Sea Ox rebuild

Post by Fuzz »

If a splash well does not work for you how about a 2x running side to side and low enough so it does not interfere with motor mounting?

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