Make rear fuel tank space into fishbox / storage

[gradydaniele]

Hello all
It’s winter here in NY and I’m seriously getting cabin fever.
Been thinking of a new a project.
The rear fuel tank on my offshore is removed I use the forward tank only.
Last year in a pinch I reinforced the lid deck with some 2x6 but couldn’t help thinking to myself wow this is a huge space in here.
Has anyone here ever made a fiberglass drop in bin to fit into this space and attach the deck lind to a hinges? This area has a drain hole which drains to the stern of the boat.
Was thinking maybe to loose the wood bracing and glass in a steel plate into the wood core of the lid so I would not need the wood supports? Inside the hole now is just raw glass has anyone ever just painted the glass and done this? Not too keen on doing this tho because maybe too much rain water could get in there. Would this be a bad idea?
Anyone ever done this?
Dan

 

[SkunkBoat]

not sure what size lid we're talking here but if you have twin tanks its probably big..

Your considerations are
Fuel lids are usually sealed. Using it as a hatch will allow water to drain into the bilge(where it must be pumped out)
Lots of boats have hatches that drain to the bilge, especially older boats. You just need to make sure your pump(s) and battery(s) are up to that task.
You will need to make sure the drain doesn't get blocked by the various stuff that will get in since it is an open hatch.(I have experienced this)
Big hatches need big hinges to trip over ..and pneumatic supports
You can paint the raw glass inner hull with bilge paint after thorough cleaning and prep

I had a similar space on my V20. about 3.5 ft long and the width of the stringers. I glassed in some wood rails parallel with the stringers and screwed down a piece of pvc board as a flat deck. I could store buckets and anchors, etc. I also added a bilge pump in the area (the space was fwd and I didn't have a fwd pump at the time)

I didn't hinge it - it was a lift out

 

[DennisG01]

It's all been done before Did something similar, as well. My boat was originally a stern drive - when I bought it, the transformation to an outboard was done, but the cockpit floor was just sort of piece-mealed together (along with floor coring rot). Take a look through these pics - I don't have pics of every single thing I did, but there might be some things in there that help you. I don't think you need to do anything as drastic as I did - just attach a hinge to the existing hatch (maybe rebuild the core if needed). I also don't think there's really any need for a drop in fiberglass tub. Just use the space as is. You can easily build a false floor (one that still drains, though) to keep items from resting directly on the hull bottom.

 

[glacierbaze]

Don't assume that the wood braces/cross members are just supporting the hatch. I suspect they are also giving some support to the deck, as well. I think they run side-to-side on my 220.

 

[DennisG01]

I agree with Glacier about the port to stbd wood bracing. I would definitely err on the safe side and, for now (until you hear from Grady, for example), that the wood bracing is there for structural integrity. In other words, to help keep the left and right sides of the hatch opening from collapsing in towards themselves.

And... forgot to include the link to the pics...
https://postimg.org/gallery/1pprbrmx6/

 

[Lt.Mike]

If that hatch needs bracing is it flexing without?
If it’s flexing it probably has a wet core. The one on my boat flexed and it’s core was soaked. I recorded it with 5/8 plywood encased in May and epoxy resin leaving a 3/4” gap of resin edge around the ply so that the new deck holes won’t leak water into the ply again.
The hatch doesn’t require any bracing and is solid as a rock.
The in deck live well idea would require a pump to remove water to recirculate as it would be at the water line. It’d make a good fish box but you’d need that pump for melted ice.

 

[gradydaniele]

When you say 5/8 plywood wouldn’t that thickness cause the entire lid to sit up say a quarter to half inch higher from the rest of the deck?

 

[DennisG01]

Did you happen to look through the pictures in my link? Some of the pics show, roughly, how to re-core. The coring doesn't go to the edge.

 

[gradydaniele]

Oh I see

 

[gradydaniele]

The foldable table looks so great propsss!
So 5/8 was thick enough huh and no bracing underneath I’m gna have to give the stuff a look
Thanks

 

[DennisG01]

5/8" is plenty. 1/2" is typical. I used 1/2" (one foam and one plywood) for the two hatches I did.

Thanks - the table was sort of a last minute thought!

 

[gradydaniele]

What kind of plywood did ou use ?
What was the benefit of He foam board also??

 

[DennisG01]

The only plywood that really shouldn't be used (although some seem to have success with it) is pressure treated. As PT ages, it outgasses it's chemicals and could cause the fiberglass to lose it's bond. Regular plywood is actually just fine if you do like I did and Mike did by completely encapsulating it. For the areas where I used plywood, I "painted" them 3-4 times, every 15 minutes, with resin before installing (extra on the edges) to make sure the resin saturated the wood as much as possible. Basically, I kept painting them until they stayed shiny after about 15 minutes of sitting. I did use Marine Plywood - it's quite a bit more expensive than standard, but it is better stuff and I don't plan on redoing it anytime soon. I did the same thing Mike did - anywhere there would be a fastener penetrating the wood, I oversize drilled the hole... filled with thickened epoxy... then drilled the final hole.

For that hatch where you saw the purple foam board... that was an experiment "for fun". There are "real" foam cores that can be purchased (pricier than marine ply, though). But the main purpose of the core is not strength... it's to separate to layers of fiberglass. So I did the purple foam board as an experiment, knowing that I could re-do it in just a few hours down the road, if needed. I did that 4 seasons ago - so far, it's still rock solid.

Benefit? Lighter and MUCH cheaper. Downside? If it doesn't last, I get to re-do it... but wait, maybe that's actually a benefit as it gives me another fun project to do?

 

[SkunkBoat]

agree NO to pressure treated....Never.

As for "any regular plywood" I would say it must at the very least be exterior grade (glue is waterproof)

Marine grade is not treated. It is a AA or AB Douglas fir with exterior glue. The letters indicate the lack of knots and defects.
You wouldn't want to use CDx because it is full of empty spaces and it is pine which is softer than fir.

 

[UCPA111]

I installed a new tank and put it in the forward location. The rear location, I turned into storage. We used the existing hatch...cut it in half, used coosa board and 1708 mat fabric and west 105 epoxy....a stainless hinge and some deck latches. Turned out real nice. Stout and has a hinge in the center (running L-R) to make it convenient to open and access. I reglassed and epoxied the compartment to reinforce and make smooth...bilge coated it. https://www.youtube.com/channel/UCATvLu ... RX0gH9FiMQ I will be adding some updates.