pullmytrigger

My sunpad/hatch will soon need to be recovered and that thing wieghs a TON!!.......Seeing its needs recovering anyway Im wondering if anyone has ever made a lightwieght hatch that stands up to three or four people sitting on it.....Ive heard of people using some stuff called DecoLite..... Can this stuff hold up???.....any other ideas???

Chart

Simply getting the water-soaked plywood and foam out will cut 1,325 pounds, and gain you 17 mph, with a margin of error of 1,300 pounds and 18 mph.


I used HDPE, commonly known as starboard. While it is not light, it won't ever absorb water, and upholstery staples stick in it very well. For more weight savings, ditch the upholstery, and use carbon fiber or Nida-Core honey comb rigid material, with gelcoat to match your boat.

pullmytrigger

Chart- I take the batteries out for the winter so I have to disconnect the ram and muscle it .......Im 6'2/ 230 and its EVERYTHING I can do to lift the hatch without the ram.........believe me........if it ever hit you in a freefall it would litterally kill you........US1 took his off and it took 4 guys just to lift it......Its gotta wiegh 400lbs......what thickness of starboard did you use????........did it hold up to people sitting on it?????......doug

32 thunder

I just had to replace all the wood on mine, and that thing took four guys to take off!!!

Poorsche

Hopefully this thread will get lot of response and pictures. When we took mine off to remove the engines we used a fork lift. THere no reason for the thing to be that heavy--and it would kill someone it it fell--

The Starbord is easy to reinforce--similar to shat I did on swim platfrom I buit could use 1" starboard and strategically placed 1" X 4" stringers glued and heat bonded together. Swim platform is 72" X 30 and wiegsh about 80 puounds.

I've got access to a starboard/acrylic fab shop here that will make them if we can get templates.

Chart

Cuda and I have the same boat, Formula 302's. He's got a few pictures of the work he's currently doing, and I'll look for some of mine later today after actually doing some client work.

On our boats there is a molded fiberglass tray with reinforcing ribs designed in it. The upholstery parts lay on top of the tray, and are screwed in around the parameter. The lifting ram is attached to the underside of the fiberglass tray.

From the factory the upholstery parts included marine plywood backers and foam and vinyl. Over the years the foam and plywood absorbed water, even though there were drain holes in the tray under it. That is where the weight was lurking, the waterlogged plywood and foam.

If you are going to use upholstery material, you need something to hold the staples, either plywood or HDPE or roto-cast plastic or something similar. I chose HDPE because it was available, machined very easy with wood tools, would never absorb water, and the marine grade plywood Formula used ONLY lasted 19 years . Might have lasted longer if it hadn't gotten as wet as often, but it's a boat that that's going to happen.

I used 1/2 inch HDPE (High Density Polly Ethylene(SP?)) which came in a 4.5' x 9' sheet. Don't know why they use that size, and I had to use a utility trailer to go get it, as that size don't fit in an Excursion. It's not light, and it's slick, so strapping it on the trailer was interesting. I THINK DecoLite is a LowDPE, and it should also work as an upholstery backing board, but won't provide the same structural strength as HDPE. [on edit: DecoLite is different from LDPE, and should provide strength if prepared corectly]

On the 302's, there is a lip molded around the opening to the engine compartment which the sundeck rests on when closed, so the sundeck is supported all around the parameter. With the fiberglass tray and the 1/2 HDPE screwed together, supported all around the edge, it's plenty strong for a couple of people to lay/sit/walk on, without much give. BUT, I walk close to the edge as it's weakest in the middle. If there were a couple of drunk topless chicks who wanted to dance on my sundeck all day long, well, I'd let them, but would expect to have to repair it before the next weekend when they would be welcomed again. After all, isn't that what sundecks are for? In a perfect world they would not be heavy enough to hurt the sundeck, so it wouldn't be a problem. Okay, back to reality....

For true light weight, consider NidaCore. It's a very strong honeycombed panel with thin fiberglass skins. It may be avable in other skins too, which might better take staples. I'm using this material to very very slowly build a race faring to replace the windshield. Jetliners use a similar material for floors, as it's strong and light. I can try putting staples in my NidaCore if you are interested, and have a way to get it. It's pricey compared to HDPE, but you'd only need one sheet either way. Personally, think it's overkill in this use for a pleasure boat, but if you are racing then every pound counts.

Finally, I've only got one season on my sundeck, including the winter. It's held up wonderfully so far. I was concerned about shrinking in the cold, as I calculated it might shrink by 1/2" at most during the cold winter months. That does not appear to have been a problem though. I built it during the hottest months of the summer, and made it as large as possible to allow for the possible shrinkage during the winter lay-up. HDPE works well with mechanical fasteners, (screws, staples, brad nails, etc) but pilot holes are suggested for screws, and don't torque down on them for the HDPE will strip out. Glues are hard to find to work with HDPE, and "welding" works better. The few glues I've heard about chemically melt the HDPE and then it bonds together during cooling. These glues are very expensive. The local water department uses HDPE pipes underground in 40' lengths, and they have a special "welding plate tool" that melts the ends of two lengths and then holds them together to cure. Lacking anything like that, I just used a bunch of ss screws instead.

In addition to the sundeck, I rebuilt the back seat with 3/4" HDPE instead of marine grade plywood. At that thickness, with the proper bracing and supports, it's quite strong and looks great. Instead of carpeting the exposed material as the factory did with the marine plywood, I left it exposed, and it gives the boat a nice updated look. The upholstered seat bottom was made from 1" HDPE, as were the headrests, and that's plenty strong.

This has been a lot to read, but if you're still awake and have any questions, just ask.

Gary Anderson

I've done a couple. The biggest on a staggered 38'.
1/2" plywood on top, 1/4" plywood on the bottom. I used 1 X 2s to fram in between. Covered the whole thing with a layer of glass and resin. It's not rot proof but I've noticed the way uphostry is attached/sewn probably has more to do with that than the materials.
Gary

Lofty

Twinn29,
We're building one now for my twin 29. It's starboard with Birch stringers. I wanted a light hatch with scoops that would take the load of two adults. This things strong. We had two big fat-azz Kiwis standing on it without braking. I'll snap some pics this weekend for you. It took about 400lbs off the boat too.

PatriYacht

Baltek Decolite panels would make a good, fairly inexpesive hatch. It's about as strong as an equivilent thickness of plywood. The fiberglass covering is thin, so you'd need to glass over it again to toughen it up. Add a couple of ribs under and your all set.

dyno

Ian where can you get this stuff and what does it cost? I always wanted a smooth hatch with scoops but the wife would kill me but I could make a spair with scoops and use it for Poker runs and stuff.