New member - deck install panga

[grouper242]

Hello all,

New member, I have read all of the sticky threads on fiberglass and decks, and this is my plan I have come up with. I am installing a new deck into my panga, which does not currently have a floor. It is a bare hull with hollow fiberglass bulkheads. Hopefully the photo shows up below. So please let me know if this sounds like a good plan. I want a lightweight deck.

I'm planning on 1/2 marine plywood with polyester resin with the following layers (only available cloth/mat is csm 1.5, 4oz cloth, 7oz cloth, 1808, 24oz woven)

Bottom: csm1.5 oz
Top:
1. Csm 1.5oz
2. Tab deck using 1808
3. Csm 1.5
4. Layer of 4oz???? Or not
5. Gelcoat with nonskid.

Finally: I want a 2 or 3 inch pvc rigging tube under the deck. How should I seal the pvc to the hole through the fiberglass/plywood? 5200 only?

Thanks for the help!

 

[alldodge]

Have not been around your kind of hull but your plan should be good. Are you going to fill with foam under the deck or use other support methods to support? Going develop another method to support the sides or are the bottom and side supports will remain?

The pvc pipe will work, and 5200 will seal, but could also use 4200

 

[grouper242]

Have not been around your kind of hull but your plan should be good. Are you going to fill with foam under the deck or use other support methods to support? Going develop another method to support the sides or are the bottom and side supports will remain?

The pvc pipe will work, and 5200 will seal, but could also use 4200

Thanks. The original bulkheads that span the width of the boat will remain, and most of them will remain above the deck. Im trying to keep the deck as low as possible for stability, and keep the factory bulkhead structure for strength.

The floors will sit within each section between the main bulkheads, and span the width of the boat. Drain tubes will drain into the bilge. I won't be adding foam. I will add a middle stringer in each section, so the floor will be supported with max spans of about 15 inches.

The teal line will be the deck height, the red is the center stringer (2 pieces 1/2 ply glued togther), and the purple dots are drain tubes through the floor into the bilge below the floor.

 

[alldodge]

ok, you should be good, so long as your not worried about the water which may get trapped under it.

If the pvc pipe is being used to run wires and such, might think about mounting it under one side of the gunnel, might be easier and provide ease access

 

[tpenfield]

Think about water drainage at the bulkheads, if you are laying a deck over them moisture will accumulate in any space, so it needs a way to get out. Also think about the stiffness of the deck vs. the span of the bulkheads. Will it feel more like a trampoline? You may want stiffeners under the deck, so as to have a solid feeling deck without excess weight (of thicker plywood).

 

[grouper242]

Think about water drainage at the bulkheads, if you are laying a deck over them moisture will accumulate in any space, so it needs a way to get out. Also think about the stiffness of the deck vs. the span of the bulkheads. Will it feel more like a trampoline? You may want stiffeners under the deck, so as to have a solid feeling deck without excess weight (of thicker plywood).

Thanks. Here is a photo showing the sections and bullkheads. Each bulkhead looks like this, with two drains through them that drain to the stern where a bilge pump removes the water. The floor you see is just loose painted plywood.

Based on the photo, do you think one center floor supports/stringer will be enough for a solid floor? I was thinking the deck will attach at three positions: the two existing pipe stringer, and an another center one which I will add, and also be tabbed all the way around (sides and front). Let me know what you think.

Orange is contact points, and blue is tabbing. Yellow is showing where the deck sections will be laid out.

I can add more horizontal bulkheads too if you think that would stiffen the floor. Thanks for the comments.

 

[tpenfield]

I would test the span with a piece of 1/2 plywood supported at the width as it will be in the boat to get a sense of the stiffness. The glassing top/bottom of the plywood will add some stiffness, but it is hard to say how much.

 

[grouper242]

I would test the span with a piece of 1/2 plywood supported at the width as it will be in the boat to get a sense of the stiffness. The glassing top/bottom of the plywood will add some stiffness, but it is hard to say how much.

Great, thanks I will try that. Do you think the 4oz cloth is needed over the 2 layers of 1.5 csm.

Or should I go 1 layer 1.5csm and a final layer 4oz cloth only?

 

[tpenfield]

I'm thinking the 1708/1808 fabric is going to contribute to stiffness more so than CSM or regular woven cloth. The cloth might give to more of the finished texture you want.

 

[flashback]

you could put removeable teak grating in it as well... just a thought.

 

[grouper242]

you could put removeable teak grating in it as well... just a thought.

Thats a great idea too. I have thought about doing that with Ipe as I have some on hand, but I am looking at adding a console wih remote steering etc, so I needed something secured to a flat floor.

 

[grouper242]

Another question - how much of a gap should I leave between the wall of the hull and the edge of the plywood, so it can be filled with peanut butter for tabbing?

Also, does the peanut butter seal the edges of the plywood, or do I need to put mat on the edges when I glass the bottom of the deck?

I will add some photos as I get started.

 

[todhunter]

I'd leave at least 1/4" gap around to fill with PB then tab in while the PB is still wet. I would soak the edges of the deck in un-thickened resin and let it cure before PB'ing in place. It may take several coats of resin on the edges, as the end grain tends to suck up a lot of resin. I wouldn't bother with putting mat around the edges as long as you plan to completely fill the gap between the hull and deck with PB. Use disposable piping bags from the grocery store which are used for cake icing.

 

[grouper242]

I'd leave at least 1/4" gap around to fill with PB then tab in while the PB is still wet. I would soak the edges of the deck in un-thickened resin and let it cure before PB'ing in place. It may take several coats of resin on the edges, as the end grain tends to suck up a lot of resin. I wouldn't bother with putting mat around the edges as long as you plan to completely fill the gap between the hull and deck with PB. Use disposable piping bags from the grocery store which are used for cake icing.

Great thanks for the tips. If I gelcoat over 1.5 csm, will I be able to see the fibers? Would 4oz cloth be smoother and stronger?

 

[kcassells]

Yes, as you see it now then that is how it will finish. You will want to fair it out to smooth for a uniform finish. Some guys leave it as is, so it has a non-skid aspect.

 

[todhunter]

I found that 3 coats of gelcoat took a LOT of the mat texture out (more than I was expecting), but it's still visible. As stated, you'll need to fair and sand if you want to fully get rid of the texture and have a totally smooth finish.

 

[grouper242]

I found that 3 coats of gelcoat took a LOT of the mat texture out (more than I was expecting), but it's still visible. As stated, you'll need to fair and sand if you want to fully get rid of the texture and have a totally smooth finish.

Thanks. What did you find worked best for fairing the floor or other areas? So far I've seen locally 3M lightweight bodyfiller, or poly resin mixed with either microspheres or fumed silica.

 

[todhunter]

I didn't fair - I glued down carpet.

 

[kcassells]

Thanks. What did you find worked best for fairing the floor or other areas? So far I've seen locally 3M lightweight bodyfiller, or poly resin mixed with either microspheres or fumed silica.

So read over the description here.

Aerosil | Phenolic Microballoons | Glass Bubbles | Fumed Silica

America's leading distributor of composite materials. Industries' best prices for fillers such as Aerosil, Phenolic Microballoons, Glass Bubbles, Non-Skid.

www.uscomposites.com

Iboats also sells these products.
West system seems popular too.

 

[76SeaRay]

On my deck, I put a bevel on the underside edge of the deck plywood where it meets the wall of the hull. Not sure if that is needed but I like that it doesn't present a sharp edge of the plywood to the hull and increases the surface area for bonding if you put down a peanut butter bead under the edge of the plywood before you set it in place. At least that is the way I did it.