Hello fellow Marinette lovers . I am new to the forum so please bear with me when I am posting my info .I have undertaken the painstaking job of replacing the deck on our beloved 1977 twin 28'express with 1/4 inch 5086 smooth aluminum plate .With the help of a VERY GOOD friend!This has been a real interesting project and a hell of a lot of work but is really paying off.I agree with Jeff what were they thinking when they installed wood on the decks of these Aluminum floating tanks!Today we put the finish coat on the deck and hatch doors.Of course we put an anti skid compound in the paint as well as sprinkled it on with a home made salt type shaker.Next week we will cut out the side walls from fiberglass 4x8 sheets and install those.I will be adding a couple weather proof LED lights somewhere on the side walls on the outside deck area.The ones I found that I like are 2"round with a stainless steel escutcheon 9 white LED's and 9 Blue LED's in each that you wire so that you can have either a white on or blue on look.Kind of reminds me of an eye as the escutcheon comes down half way over the round light and directs the light more down in direction.I have taken numerous photos along the way and will start posting them and a tutorial as my time allows.Guys this is the only way to go it does cost more but it will increase the value and longevity of your aluminum baby!
Steve

Ok here we go,4-6-09 day one .The weather had been great the week before we started this project.We towed the boat from South Haven to my friends driveway 40 miles east of there.This is because I could not fit it in my big barn 80'x 24' on account of the door height of 9'. ( boat on trailer 10'6")This worked out great though because my friend has more of the metal working tools than I have . He is a tool and die maker by trade.We left the shrink wrap on and worked under it and in his shop ( two car garage )the times we needed to which was a lot .Even though My buddy has a bridgeport in his shop we never used it as all the pieces are too big.Day one I woke up to two inches of snow and 30 degrees but under the blue tent we felt very comfy with a small space heater blowing all the while. Day one we removed al the interior walls and the old nautilex covered marine grade plywood that was getting soft in spots.The old deck was replaced from the fellow I bought the boat from .It was probably 12-15 years old .We have owned the boat 8 years now . How they managed to screw so many screws thru the aluminum angle framing into the plywood from the bottom at the angles they did is a real trick.I think they must have employed a couple dwarf contortionists.Taking those out carefully was a real pain in the neck literally.We needed to be careful as not to just rip up the old deck because we wanted to use it as a pattern which we did.The rear hatch door you see in the photos I replaced two years ago because I put my foot thru the old one.I had a local guy who specializes in aluminum and stainless fabricating make it up for me .I supplied the engineering (drawing of what I wanted) and he made a beautiful rear hatch with a 2" flange which I set in a bed of caulk and tabs on the inside that I screwed to the framework inside the opening. (NO screws into the decking !)Of course I wanted to reuse this beautiful piece of work but made sure I painted it because it got so fricken hot you could fry an egg on it (we put a piece of indoor/outdoor carpet over the thing while aboard. The 2nd photo is of the bare wall framework after we tore out the old fiberglass walls.The old walls and the new walls we are going to install are from 4x8 sheets of fiberglass sheets .Yes the kind you see in bathrooms kind of an eggshell finish but really hold up well and look great in white!The 3rd photo is of framework around engine area.The 4th photo is of framework around the fuel cell.The next photo is of the framework after we sanded with a angle grinder paddle disc. The next photos are of starboard and port engine areas.The next photo is the blower side framework.I had to remove the blower and check out as it quit working at the end of last season.It turned out to be fried and I found a direct replacement on e-bay for 49.00 plus shipping .It is a mayfair 120 cfm remote mount. The next photo is of great interest although I have not figured out exactly what it means .I know that the boat is a 1977 vintage and that the guys who made it probably started it in 1976 . A very good year by the way .Not only was it the bicentennial of our great country but it was the year I was married to the most beautiful woman on earth! The next photo is of the gas fill tube area notice the grounding wire .The first day we accomplished the complete tear out and cleanup and now we have our pattern. Time 8rhs.

..."Jeff what were they thinking when they installed wood on the decks of these Aluminum floating tanks!"

Damned if I know! Even the shower stall floor is aluminum, but not the cockpit deck. Go figure.

I like your solution! That deck will last forever.

Jeff

PS: Welcome aboard.

Thanks for the welcome I appreciate the wealth of knowledge and experience most of you members have to offer !]
Steev
Now for day two.We used the old decking for the template and cut our main patterns this day.That's me holding the cut off pieces from the curve of the aft deck ...We also fabricated new scuppers.At first we were going to cut out the corners of the aft deck to router the aluminum down on the bridgeport and weld back onto the plate then install the old strainers the same way they were in the wood deck. But my very clever friend came up with using the strainer as a pattern and drilling all the same size holes thru the decking then grinding just enough metal away to a kind of cone shape with the right amount of grade for the water to follow out the drain tube.We then drilled thru the deck and bottom half of the strainer and connected with rubber gaskets silicone and stainless fasteners with nylock nuts.(all fasteners stainless of course)This redo took drilling out the metal about 3 times with a different size bit each time increasing the hole each time using cutting oil all the way .We used a cordless drill for all of our drilling and tapping throughout the project.We used a skill saw with a carbide tip blade for all the aluminum cuts we made except for some inside corner cuts which we used a pneumatic reciprocating saw or saws all or dremil.My friend JW siad he has cut aluminum up to two inches thick with a skill saw and carbide blade.You go slowly and use a good cutting oil and it goes thru the metal like a hot knife thru butter!Amazing !! Time 8hrs
PS
notice the rear stainless hatch with the tabs for fastening!
I was taking the photos as we progressed.Honestly fellas I did half the work here on this project except the mig welding ! :>)

I notice that Hamilton Marine has foam-and-fiberglass panels with a density of 26 lb/ft3. Hard to argue with the aluminum (beautiful job!) but some might prefer the panels, at around 277 bux for a 4 by 8.

http://store.hamiltonmar.../browse.cfm/4,36821.html

Day 3 of deck replacement.On this day we installed the other half of scuppers,locate and installed recessed tie downs and eye pads for strap hook of cockpit canvas tie downs. Gasket making was part of the job as well.We then dry fitted the decking without the riser bracing to make sure all would fit right.It fit better than Oj's glove I'll tell ya ! No adjustments were needed!We also locate and cut access panels for outer spark plugs on each engine and also for the port side engine water pump. Notice cut out for under helm console as well (The pump access is the first improvement I made to our boat when we first bought it .It turned a two hour job into a 40 minute job)So I made sure to include one on the aluminum deck only bigger!I was so tired of scraped up arms ! JW cut the riser braces and welded to the port side of aft deck . Notice his slits in the bracing to fit the contour of the curve. We used 2" x 1/2" channel #6061 this makes the deck to be a total 3/4" .JW had a problem with the feeder on his mig set up The aluminum wire is so flimsy compared to other wire the thing was jamming up every 5 minutes. The next day he went to the welders supply to get more wire#5356 and the fellow at the counter advised him to go up one size on the feeder orifice and presto it never jammed again during the project.(JW was using the recommended size for his welder for this wire to start with ) Shows you what they know ? Time 8hr's

The only thing missing here (I love the scuppers) is cost information. Suitable 1/4" plate in 4 X 8 seems to be around $350, and on top of that, the cost of the hatch. So this would be a $1000 job, minimum, not counting labor?

When I did my deck I bought 3 hundred 3/16" fine thread, countersunk, allen head screws from smallparts.com

Then I drilled and tapped them into the deck frames. If your plating is not 3/16" thick then you will have to go with smaller screws to get the thickness for the counter sink.

I plan on giving my cost of the project at the end of this informational Project log.I will tell you that the aluminum sheeting and channel was a tad over 1,000.00
Thanks for the compliment on the photo documentation.I always try to do this with all my projects. Stay tuned more to come !Wait till I send you the link of the 63 foot aluminum custom made yacht that I got my insulation idea from .It is real sweet and if I win the mega millions I will have one commissioned to be built for me and the wife.Ha

Day 4 ,We set our goal for this day to finish cutting and welding the riser braces for aft deck starboard and the rest of decking. I also cut a new aluminum brace to mount the fuel water separators and remote oil filter on.There was an old wooden one I wanted to get rid of ! Also started to cut the patterns for insulation which we glued to the under side of all the aluminum decking and doors.
The insulation is of great importance it not only deadens the sound from the engines but prevents the aluminum from condensation that would drip all over your engines and everything else in the bilge.After I researched what would be the best insulation I found some guys that did all the leg work so to speak and found the best solution.It is called armaflex and is used in refrigeration to insulate a/c duct work
and refrigerant lines.I found this stuff through Johnstone supply co. in 4'x3' sheets x 1/2 " thick. I also had to purchase the adhesive to glue it on.The other guys bought it with a self adhesive backing but too cost prohibitive for me .I think this will be the cats meow.I then bought and sprayed on other areas are you ready for this ?The black gooey crap everyone seems to despise!Actually undercoating for cars. It worked great .made by 3 M.This will keep the rest of the aluminum frame work that I could not armafex from sweating .I am going to cut 18 inch squares out of thin aluminum sheeting (boiler tank wrap) and glue onto the armaflex above the flame arrestors just in case so a flame will not deform the armaflex.I found out armaflex is closed cell insulation and will not mold or mildew yeeeha.This would be a good fix for the bow hatch condensate drip problem everyone has with this model boat.You can bet I am going to replace the carpet square the previous owner had put above the screen. I must say though, it did work beautifully.Thanks Denny!Of course we ground all welds smooth,cleaned all aluminum with a degreaser then DA sanded entire surfaces followed by a solvent wipe through out the entire project.
S

I have 3/16 aluminum directly over the framing. It's quite solid because there is so much framing supporting the deck. I got a gallon of non-skid paint for it but found I didn't need it.
Will post pics if I can make the computer work.--Ed