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1972 20ft Dusky rebuild

Old 07-02-2020, 07:40 AM
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Default 1972 20ft Dusky rebuild

Hello everyone,
im new to the forum but a long time lurker if this website. Im 22 years old and just bought my first big rebuild project. Its a 1972 20ft dusky that needs an entire deck rip out, stringer repair, and transom repair. I got a couple questions I am hoping some of yall could help me with. For laughs I did a moisture meter to the deck and transom and it came back at over 45% even in the spots I thought would be at least a little dry!

1) Im going to be working with SpaceAge composites for my coring and its basically a rival brand of the coosa blue water 26 and was curious if anyone has worked with it before?

2) when I cut a test spot in my deck it ended up being about 1.5 thick which was really thick to my surprise and i feel the typical rule of thumb is to put in what you take out but I was planning on doing 2-3 layups of 1708 on both sides of a 3/4 composite board would this suffice? It should make it about a 1 board after the layups.

3) the stringers i believe are foam cored and pretty brittle I was able to crush a part of it with my hands. Should I redo the foam core? I was thinking about rebuilding them with composite and obviously keeping the original design in the process. Possibly adding a bulkhead

4) the transom measured in at just shy of 2 just curious on if I should use two 3/4 boards or one 1.5 board And glassing it all in. The two 3/4 birds would be glued together with cavaseal and mesh glass.

any help is awesome! I will post pictures soon!

Last edited by Mailbox; 07-02-2020 at 11:37 AM.
Old 07-02-2020, 09:56 PM
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On a 72 the stringers are definitely wood
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Old 07-03-2020, 05:46 AM
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Cool project post some pics! Are you working in epoxy? If so You should go straight 1700 it will save a ton of resin. Buy the thicker transom core material if the price is similar doesnt seem like much more work to put two layers in but save time everywhere you can. Im working in wood on my project, but seems like the standard for foam floor layups is 2 layers 1700 both sides. If your going to put this amount of work and money into the boat definitely replace the stringers, if you can crush anything structural with your hands it needs to be replaced.
Old 07-03-2020, 07:21 AM
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Check out the build threads on here. Tons of info. Are you planning on epoxy or poly/vinyl?
Old 07-03-2020, 07:35 AM
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Planning on using 2:1 epoxy.
Old 07-04-2020, 02:49 AM
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A 3/4deck with 2 layers of 1700 or 1708 is plenty thick. The mat on 1708 layer mat out on your final deck skin will ease fairing and the need to fill the weave. 2 pieces of 3/4 Coosa will be stronger than a single 1 1/2 piece since there will be twice the roving in the 2 piece core but it really depends on what you plan on hanging of the back off it. My price for 1 1/2 is less than the price for 2x 3/4. If they are boxed foam filled stringer Id lean towards rebuilding them buy cutting the tops of, removing the foam and then refilling and adding glass to strengthen them. If they are wood, remove and replace. Post some pictures when you can and good luck.
Old 07-04-2020, 05:44 PM
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Just finished up a 278 1982 Dusky rebuild. I went with two 1 inch Coosa sheets for the transom and wood for the stringers and bulk heads. I used Arjay to bond the sheets together with a layer of 2oz Matt on each side which was sandwiched with Arjay. Wood is much easier than Coosa to work with. Coosa is hard to cut and makes some nasty dust. Also Coosa doesn't have the same screw retention that wood has. Wood is much cheaper so mistakes wont hurt your wallet as bad. As far as the deck lay up... I went with 3/4" with two layers of 1708 on the bottom side of the deck and two layers of 2oz Matt on the top side. Sounds like you've got a lot of grinding in your future...Make sure you have a good respirator and plenty of extra cartridges. I also used vinylester resin which was cheaper and easier to sand then epoxy (just my 2 cents). Good Luck! There is a ton of threads on here with great info!
Old 07-04-2020, 08:16 PM
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Had to have 10 posts for pictures!

1972 20 Dusky. Calm before the storm


Looks pretty filthy


Console is taken off. You can see where I couldnt scrub after all my bleach. Also ripped out all that wood up forward

Wet! There is drywall screws that were never bedded properly. Im going with the screw less approach. Going to use cavaseal or some type of epoxy and use screws to hold it down tight then, take the screws out and fill holes with epoxy.

Wet!!!

Put a hole in the stringer to see material. Dont know if its foam cored or just that rotten.
Old 07-05-2020, 06:13 AM
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Nice project you have started.

It looks a little like someone put a second layer of 3/4" plywood over the original floor. It will loose a lot of weight when thats gone! Depending a little on what core you use, 3/4-1" is about right for the floor. The core material you mentioned looks like its a great product but if your in south Fl. you may do a lot better on the price (when you consider shipping cost) if you look at a few of the companies more local to you.

Old 07-05-2020, 06:51 AM
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You have received great advice! Listen to Seabird. Im on my second rebuild and will offer advice based on what Ive learned the hard way. I chose U.S. composites for my material. I used their 3:1 epoxy and most of my glass was 1700 and 1708..
Ised 1708 in a few areas. One single layer on outer transom skin and on layer on top of deck. Reason: You want that outer layer to be 1708 so you can sand it without sanding through the biaxial cloth. In other words that top layer of chop on the 1708 becomes sort of sacrificial if that makes sense.The underside of deck will do fine with a hot coat and two layers of 1700. The topside go one layer of 1700 and then a layer of 1708 chop side up.
Tab everything good and you will have a sweet ride.
If You run into anything that leaves you scratching your head feel free to holler.
Thats a great hull!

If I was going to use composite, Id pop small holes all over it, put a hot coat of epoxy to fill them then lay the glass. All in one pour. This will better affix the lay up to the board as composite does not hold the epoxy/glass as tenaciously as good old meranti marine ply will.
Please dont take that as a slight on using composite. It certainly has great benefits!
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Old 07-05-2020, 08:17 AM
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great bones already a three piece layout which is awesome. Cut that floor out and leave about 3inch lip wround the perimeter to mount the new floor. Tyvek suit 7inch grinder with 24 grit disk crow bar and a sawzall and go to town! Beer too, lots of beer Build some supports for the hull when you take the stringer system out, you need to protect the shape of the running surface so it doesnt deform.
Old 07-05-2020, 08:33 PM
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Dusky didn't foam core stringers in 1972, I don't think that even became an option until the late 90's. The glass is the strength of any stringer
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Old 07-06-2020, 09:11 AM
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Originally Posted by Team Seaside View Post
Dusky didn't foam core stringers in 1972, I don't think that even became an option until the late 90's. The glass is the strength of any stringer
So do you think cutting the cap off the stringer and removing the old material then, using a foam cored stringer would work best since the coring material isn't taking the load just the new glass layup around it would be? Material cost wise this would be great too.

I will have more pictures up in the next few weeks, I am going up north to do some electrical work to my stepfathers charter boat (The Floridian a 61' sportsman) it hit a nasty wave in The big rock tournament and tore the front anchor locker off and is getting work done near Jarrett Bay.
Old 07-06-2020, 03:45 PM
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The wood was structural so if you move to replacing it with foam youll need a much heavier layup.

I know that boat and saw pictures of the damage. I was amazed she made it in like that. Hell of a thing that was.
Old 07-08-2020, 09:13 PM
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Originally Posted by Mailbox View Post
So do you think cutting the cap off the stringer and removing the old material then, using a foam cored stringer would work best since the coring material isn't taking the load just the new glass layup around it would be? Material cost wise this would be great too.

I will have more pictures up in the next few weeks, I am going up north to do some electrical work to my stepfathers charter boat (The Floridian a 61' sportsman) it hit a nasty wave in The big rock tournament and tore the front anchor locker off and is getting work done near Jarrett Bay.
I'm not a stringer expert but I'd cut them down to the hull and rebuild them with a composite material like coosa or wood if coosa is too expensive. I wouldn't try to save the old glass and fill them with foam. You're there now, just do it right and be done with it.
Old 07-10-2020, 10:58 AM
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Subscribed.
Old 07-12-2020, 05:12 AM
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keep cuttin!
Old 08-02-2020, 05:09 PM
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Hello everyone. I returned home from my stay in Beaufort the last few weeks and am amped up to get dove into my project. The Floridian (a 61 sportsman that many people know that its bow practically broke off in the big rock blue marlin tournament) came along super smooth and is projected to be in the water next week! As for my dusky I got home yesterday 8/1/2020 and today Sunday 8/2/2020 I ripped out most of the deck. I probably removed nearly 800lbs of wet wood with plenty left to take out. After I got done I took a pretty good look at the stringers and decided they needed to be completely redone. Somebody decided to use a 2x8 or something of that nature to bulk up the stbd side stringer and did a horrible job they only wrapped the glass halfway down the board and wasnt even resin coated. I have a few questions regarding the fuel tank, it is a 32gallon fuel tank just curious if it is worth keeping and getting pressure tested or if I should upgrade or downgrade the size?

Wetttttt


Need to redo that center stringer BAD

Weird layout on this stbd stringer


Last person inside here only lasted up half the board with glass. My guess is just to help with fuel tank support?

Got a lot of grinding cutting and cleaning ahead of me
Old 08-02-2020, 09:03 PM
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Man that is a soggy nasty mess. Definitely need to go scorched earth and tear out every single bit that is not hull skin. The cost of a new tank will be a pittance compared to the rest of the money you spend here so just put reusing the old one completely out of mind. I would probably bump the capacity up to 50-60 gallons but that depends on where youre fishing. I put 100 gallons in my 23 Mako.
Old 08-03-2020, 06:49 AM
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100% agree dont waste time messing with that old tank. I replaced one stringer at a time, in order to keep the hull from flexing or twisting. just my 2 cents.

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