How to make a deck fit back into it's cavity (PICS)

[Picflight]

I ask this question to the audience of this forum because the skills and knowledge I have observed is unsurpassed.

I had some repair done to one corner of a removable fuel tank cover which is also the floor of the cockpit.

After the repair, it does not want to fit flat. I have spent a few days grinding with a 4" grinder taking off the high spots, putting it back in to test the fit but there is still some adjustment needed.

I am using an inspection camera through the inspection port to see all around the edge using sunlight as my guide and mark the dark areas for grinding.

The technique I am using does not seem efficient. The cover weighs approximately 150lbs and it is not easy to take in and out of the boat.

What are the tricks, tips to have it sit flat? Am I missing some other trick to mate the two surfaces?

I also thought of some how making a mold of the 2" ledge where it sits. I thought of using pour foam to make a male plug and then glassing the 2" ledge to build the mold and use this mold over the cover to check for clearance and grind instead of picking up the whole cover back into the boat. The fiberglass shop I went to get the supplies for pour foam advised me on the difficulties of using foam as it wants to stick to everything and I should be careful on how I mask and prepare the surface.

• Deck upside down
  
  
• Foots I installed after the repair was done to have it sit on the ledge
  
  
• This is where it has to fit
  
  

 

[Brian D]

Although I cannot help, I am wondering which of the two surfaces are warped? I would think the inspection deck is warped somewhat to prevent the deck from fitting flush.

Have you by chance taken a regular piece of ply and cut to form then let it sit in place of the deck to see what is happening. It sure would be easier to lift out instead of that 150# deck.

 

[Picflight]

I don't think it is wrapped, the cover, since it was sitting nice and flat when I took it out. The 2" ledge on the boat where the cover sits is nice and flat, checked it with a 4' level.

The cover is an 1" thick with marine plywood sandwiched in fiberglass. The whole cover is 48"x65".

 

[Brian D]

What "repair" did you have done? It would appear that the repair changed something. Maybe the "high spots" are not really high, but the low spots are indeed too low and need to be built up.

I am patiently waiting for someone with more knowledge than me to appear. LOL

The reason I ask about the low spots has ties back to installing satellite antennas on boats. We were taught not to add weight to the unbalanced side of the stabilizer bars but remove weight from the other side. If that makes any sense to what we are discussing here. LOL

 

[Picflight]

It does make sense Brian, the art is finding the balance spot.

The repair was done to arrest the beginning of some water intrusion into the core. It was an approximate area of 1 sq foot as depicted in my crude diagram. The foots that I installed were the low spots in the repair area.

The white area you see on the underside is gelcoat sprayed to make the whole area look pretty. The fiberglass repair gentleman suggested it to make it look nice and even. The original underside was just bare resin and glass.

 

[Brian D]

OK... wish I could be of more help trying to find the pivot point of the deck. Hopefully someone will be along who knows fiberglass and deck work.

 

[jeepsailor]

Might I suggest something along the lines of what I dentist does when trying to make things meet up? How about getting some simple clay or play-doh. Roll it out into a bead, fill the gap, cover with plastic wrap so that the cover doesn't stick, and then lay your cover back in and evenly press it down. That should give you your high/low spots and tell you where you need to grind/fill to even things up. If the cover is high anywhere on the top, you obviously need to start with thin spots to grind down until the cover is flush. If the cover is flush, then you just need to bring the low spots up. And the playdoh should tell you where and how much.

 

[Picflight]

Excellent idea Jeep, definitely much simpler than trying to build a mold.

The cover being almost 150lbs and flat, it has to be slid 1/2" or so to set in place. I place the front first and let the back lay on a 2x4 and then lift and remove the 2x4, it is a two person job, to set it down. During this time, I can see the play-doh getting compressed in places where it might give false readings.

I should try this before I set out buying $100 worth of mold building material.

 

[Brian D]

Cut a groove in the 2x4 where you think the Play-Doh will get compressed.

 

[Winkfish]

Do you think part of the cover might be hitting on the tank itself or a fitting? Taking it further, are you certain the tank is down as far as it should be, or might there be something under the tank holding it up higher at some point?

 

[Picflight]

Nothing else is touching the cover. The tank is in place and has not been removed, all is OEM fitting. I have looked all over the inside with a high resolution inspection camera.

 

[rpwillia]

How about how you set a sink on a vanity

Most of the ones I have done, they just have you run a bead of caulk all the way around and set the sink top and and let the caulk solidify. Or perhaps I just don't have the vision of what you are doing?

 

[Lake Superior Sailor]

Strips of carbon paper laid in will mark all the high spots,Same way the dentist shapes a filling!........Dale

 

[Winkfish]

You can buy or make some thin and small shims and keep puting them in and taking them out to try to narrow down the low/high area.

Also, as for the weight of the cover, is there a halyard there that you could use to lift it?

 

[StinkBug]

Ok, just because it was flat when you pulled it out doesn't mean it's flat now. Obviously if the piece was sitting flush before the repairs and it's not sitting flush now then something has changed. You mentioned checking the area the cover sits for straightness, but not the cover itself. Seems to me that having it out and unsupported may have warped it. Or something about the repair process warped it. You cant have 2 perfectly flat pieces that dont sit flat on each other. How is it held in place? If it gets bolted down, what's wrong with just tightening down the bolts til it is solid?

 

[Picflight]

@Stinkbug,

The cover is not flat and the reason is the repair. It is a lot of effort trying to lift a 150 lbs piece after each grinding effort to try and mate the two.

The cover is solid 1" thick and it just sits on the ledge, I doubt that it can wrap so easily. The problem is obviously the areas where the repair was done and the gelcoat spray over the entire surface.

The cover is screwed in around the perimeter and the screws are meant to hold it in place. I will not use the screws to cinch it down because that will make the problem worse down the road. The force of walking around will flex the cover and lessen the screws and seal.