# 87 Dolphin backcountry project boat



## dania02525 (Oct 25, 2021)

Hello all!

I just picked up an 87 dolphin backcountry 18 needing some work. Its a good running boat, had it out on the water running around before buying it, but its going to need some glass work and outboard maintenance before I use it- Its got a 2015 etech 90 that runs great. 

I've got floor cracking where the floor meets the gunnels, seems to be associated with the fuel tank I just removed. It will be my first time working with fiberglass so diving right in I guess. I was able to see the center stringers and they looked fine to me, but sill need to open up the floor to get a peak at the outer stringers. Evidence of a (poor) previous repair on the same cracks, so definitely a recurring problem. I've read somewhere that this vintage of Dolphins had issues with the floor separating from the stringers so I'm hoping thats what I'll find under there and that 40 years of the heavy gas tank pulling up on the floor is responsible for the cracks. If not, I'll be learning structural reinforcement fiberglass techniques!

What would be the best way to cut access holes into the floor to check the outer stringers to make it as easy to repair as possible? should I try to drill a hole and get an inspection camera in there instead of cutting holes, or cut a bit of material out parallel to the stringers?


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## Mike Haydon (Dec 19, 2019)

From the inside pic with as little light as you had the stringers looked good. It honestly looked like the floor wasnt bonded to the stringers with epoxy or bonding putty, peanut butter, what ever you want to call it. Can you try and get some more light and take some pics of the stringer and the deck where they meet?


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## dania02525 (Oct 25, 2021)

Here's a shot next to the console access port, whatever epoxy it was seems to have crumbled. I also removed some of the old fiberglass up front, and the floor definitely slaps the top of the stringer when hitting it, so it's not attached. Going tonight to grab an inspection camera at harbor freight to give it a close look all over.


I was thinking if this is the reason for the cracking, I could screw an eyelet into the Deck, tie it up to pull it away from the stringers a bit, then drill holes through the deck over the stringers and inject epoxy. I'll get some much better pictures with the inspection camera


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## Steve_Mevers (Feb 8, 2013)

I would take my time and cut out that front portion of deck and do it right, you might even be able to put the old section back in after making repairs.


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## ek02 (May 8, 2012)

That's a great, hard to find skiff. I guess the tank was removable without taking the cap off. That's how Jack Broyl used to build them in the 80's. Hopefully yours has no wood in the transom or stringers. The newer Super Skiffs and 18 Backcountries don't have easily removable tanks even though it looks like they can be removed. There are 2 screws in the front of the tank that are not accessible without removing the deck. They put what looks like a removable panel in the front bulkhead of the my current Super Skiff that has another bulkhead behind it. The Super Skiff Jack built me in 1994 had an easily removable tank. Good luck with the restoration. I'm curious to know if the outside stringers are ok.


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## dania02525 (Oct 25, 2021)

Steve_Mevers said:


> I would take my time and cut out that front portion of deck and do it right, you might even be able to put the old section back in after making repairs.


Which part would be best to cut out? Is it a bad idea to cut across where I walk on? Next to the fuel tank? Just want to make repairs as easy as possible for myself. 


Grinded away the old repair, found a bunch of epoxy and the floor I think would come out with a two cuts across it, one about a foot back from the bow.


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## dania02525 (Oct 25, 2021)

This is turning into a build thread, hope in in the right sub forum! So yeah, epoxy didn't bond too well to the hull it looks like, so I think this will come up in one piece with two perpendicular cuts. I don't want to make a dumb mistake cutting in the wrong spot, if any of you have advice on the least dumb place to cut this


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## Steve_Mevers (Feb 8, 2013)

Wherever the previous owners repair stops is where I would make a cross cut. I would use a skill saw with the blade set just deep enough to go through the deck.


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## dania02525 (Oct 25, 2021)

Steve_Mevers said:


> Wherever the previous owners repair stops is where I would make a cross cut. I would use a skill saw with the blade set just deep enough to go through the deck.


Yeah, makes sense, I've been using an angle grinder, I'll be super careful not to cut the hull or the stringers. Will get some good pictures once it's off


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## lemaymiami (Feb 9, 2007)

"This is turning into a build thread"... That's a very common thought by most as they tear into the deck on an older skiff... If it were me and I found the stringers to be compromised... That's exactly what the game plan would be. Instead of trying to save deck and stringers - I'd be replacing them, doing it right means not ever having to tear into it again and not to mention the peace of mind of knowing you've got a solid footing under you feet out on the water... Stringers, deck, and new fuel tank (and all of the hoses, vents, fills..). 
As you tear into your troubles, make a point of taking a really close look at the transom as well (and if you're not sure what you're seeing - have a pro look it over..). If the deck and stringers are in trouble - the transom may be as well... 

The good news, however deep you end up into that old hull, is that repairs can actually make it better than it was when it was brand new... Frequently that will be your only consolation if you end up diving deeper than you ever planned... 

Good luck and post up what you find (lots of pics) as well as your repairs - even if it has to go to a shop for some professional attention.. We'll all be watching...


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## dania02525 (Oct 25, 2021)

A Fiberglass question: Should I be using 6" 1708 Tape for the repair here? I have some 8.7oz E-Glass 4" width woven tape here, obviously the 1708 will be stronger but which will resist cracking more?


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## dania02525 (Oct 25, 2021)

Got the bow part of the deck off. Stringers seem to be ok, definitely seems to be a deck to stringer adherence failure- built on a Friday maybe. Current plan is to order 50yd of 1708 6" glass. 


I'm going to fix the bow part of the deck and put it back together for next year's project, the whole deck should all be done but I want to get it out on the water now that I know it's not structural. I don't see any harm in doing it in sections. Plan is to lay up two layers of 1708 on the hull first, chisel off the peanut butter that is on there and mix some new stuff up thick enough to actually touch the deck, then glass in the floor all the way around.


















Inboard port stringer:









Separated peanut butter:









Guess they couldn't spare the resin when it was made, floor came up pretty easy though:









Outboard port stringer:









The mess of epoxy from the previous repair, hopefully there is enough fiberglass under this to use!









Outboard starboard stringer









Inboard starboard stringer:









Deck section I took out, see where the peanut butter separated from it?


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## Mike Haydon (Dec 19, 2019)

Personally I wouldn't try and bandaid it together to use it in the meantime because your repairs wont be as strong as doing it all at once with a solid plan. I would take it about a half inch inward of the old repairs so you can then grind back and fine tune everything. Then use your bonding putty correctly with spacers and all the way around the repair. Taping after all that and tiring into the hull will give you many many years of worry free boating.


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## Mike Haydon (Dec 19, 2019)

To your tape question I would use both as long as it came from the factory in those widths. Cutting 1708 or similiar down can leave your matt pulling apart from your cloth. Just use both in consession. Some would say go larger to smaller and some the other way. I'm not trying to get fussed at by others on here so I will leave that portion of my 2 pennies to myself. Lol


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## dania02525 (Oct 25, 2021)

Mike Haydon said:


> Personally I wouldn't try and bandaid it together to use it in the meantime because your repairs wont be as strong as doing it all at once with a solid plan. I would take it about a half inch inward of the old repairs so you can then grind back and fine tune everything. Then use your bonding putty correctly with spacers and all the way around the repair. Taping after all that and tiring into the hull will give you many many years of worry free boating.


Yes, I cut away all the old repair already. Plan on layering the underside of the existing peice before taping it back in to make it stronger around the edges, it was all epoxy anyway. This piece will be permanent and strong. The part I'm deferring is cutting out the rest of the floor to make the same repair as this. The rest of the floor isnt cracking, but it also seems to have poor adhesion to the stringers.


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## Mike Haydon (Dec 19, 2019)

Honestly that a decision only you can make. If its sold now it may not be later. Question is how long? It's kind of a pay me now or pay me later. Your boat is already down, why not fix it once and know it will be good forever


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## dania02525 (Oct 25, 2021)

Mike Haydon said:


> Honestly that a decision only you can make. If its sold now it may not be later. Question is how long? It's kind of a pay me now or pay me later. Your boat is already down, why not fix it once and know it will be good forever



If I knew what I was doing, then yes, I'd do it right, once, and forever. I don't know what I'm doing though and this repair might not last. If it seems to go well, I'll have the confidence and know how to do the rest, and then paint and polish up this boat like new. I've always been taught to start small when you are learning, since it's much easier to redo a small thing when learning along the way. I'm hesitant even to use epoxy to glue this floor down in case I need to remove it again!


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## MikeChamp12 (May 17, 2021)

dania02525 said:


> If I knew what I was doing, then yes, I'd do it right, once, and forever. I don't know what I'm doing though and this repair might not last. If it seems to go well, I'll have the confidence and know how to do the rest, and then paint and polish up this boat like new. I've always been taught to start small when you are learning, since it's much easier to redo a small thing when learning along the way. I'm hesitant even to use epoxy to glue this floor down in case I need to remove it again!











that’s what I’ve been saying. Look at me know……


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## dania02525 (Oct 25, 2021)

This was enough weight to hold the floor down into my epoxy:










Notice the dry layup. This is our first time using fiberglass, and we learned not to be stingy with the resin, not to mix more than is needed for one piece of glass at a time, 1708 doesn't like bends, and finally that it's going to be much easier to wet out both sides before laying it down. This work here wasn't strictly needed, it's really just to provide a little more rigidity to the edge of the deck, and to keep peanut butter from falling in the hole so I decided not to redo it.









1. Three layers of 1708 on the deck piece to reinforce it and to make up an inch or two of missing glass on the edges. Did this Saturday morning, and I think we ended up too dry on the resin, since the glass seemed to have a lot of white spots. Next time I will pre wet both sides since it's like 85 degrees here and you just don't have time to work the resin all the way through the 1708 from one side. Trimmed to fit perfectly.


2. Mixed up some ketchup like epoxy with cabosil to run a bead along the edge where the edge of the deck piece meets the hull ( mostly my dry fiberglass, careful not to let it get out above the deck. Also mixed up some peanut butter consistency epoxy and put it in globs along the stringer before putting the deck piece back in. Epoxy was was less smelly and much easier to work with after chilling it for an hour while we prepped.

Next I will mix up some polyester peanut butter to fill the gaps between deck and hull, and to give the 1708 a better radius when tabbing in the deck. Going to wait for the epoxy to fully set though.


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## dania02525 (Oct 25, 2021)

Filleted the edges with some resin thickened with cabosil, then layed three layers of well soaked 1708. It came out much better this time, what looks like bubbles here is actually some of the old filler showing through.


Hopefully it holds up, this is the best I can do with it! Will add some white gelcoat tonight and a layer of pva to help the gelcoat harden and I'm good to start on the outboard


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