87 Osprey 22.2 rebuild

[305kingfisher1954]

[RickK]

Nice backdrop.  Are those lobsta traps?

[Capt Matt]

This was my first and only boat build, although I have seen lots of other rebuilds in person and did lots of research when choosing my building materials. When ever composite one recommended a density I went up one more level as I figured what could it hurt and I did not want to build to mass production boat spec's.
My friend who builds lots of mullet skiffs from scratch and rebuilds 24 Morgans gave me a hard time about building a tank and that I was way over building and over spending. Most rebuilds where I live only use marine plywood and mat and never even biaxle let alone coosa.
I opted for the staggered joint method when building my stringers, it just seemed to me like a stronger way to go. Besides the 26 pound bluewater coosa every other density I researched claimed to be 30% weight savings or better.
During my build I put a scrap piece of Bluewater 26 between two concrete blocks and jumped my 250 pounds up and down on it and could not break it.  Its crazy strong and I thing the ultimate transom material.  As for building stringers they are really just a form to hold the fiberglass so 15 pound is plenty that is why I chose 20#. I recently saw a rebuild using 2 inch thick nida core for the stringers with 3 layers of biaxle, The stringers had no strength but with all that glass I don't think it even matters
Capt Matt

[slippery73]

Are you set on scrapping the existing stringer system?  

I would reuse the existing system if at all possible. Its going to be stronger than the coosa setup your talking about. The trapezoidal structure is inherently strong, its what most bridge structures are made of. Every major boat builder today uses a trapezoidal grid stringer system, aquasport was one of the first production builders to use this system. A testament to its strength is the number of 40year old boats on the water still and their loyal following.

The problem the factory stringer system has is with the attachment of the stringer to the hull. I'd retab the stringers to the hull with epoxy, then add additional laminate in the hull bottom and up the chine to the deck bottom.  Do the same through the center of the boat, epoxy in the center keel board, etc.  I'd also add another layer of glass on top of the stringers, then over the entire stringer.

By keeping the original stringer system you'll be better off in terms of strength, should be more affordable, and a future buyer may be more comfortable knowing the stringers weren't cobbled together by  a fiberglass huffer not an engineer.

[Capt Matt]

Some higher end production boats that are using the grid stringer system are Lake and bay, Jupiter, glacier bay, hatteras world cat, edgewater, ranger, shaefer and dorado.
Capt Matt

[305kingfisher1954]

No Slippery, I'm not set in how to repair the stringers..I just want to do it the best way since I've commited myself to doing this project...I have moments that I ask myself , "What did I get myself into "!!..I woke up this morning with the plan to do it like Matt had stated...Double
1 inch Coosa (20lb density) with staggered joinnts and bulkheads at the deck joints...But now you after reading your post, you have me re thinking this..Hard to decide when you don't have any experience on these rebuils..It would certainly be less expensive to work with the existing stringers..I noticed on Baysides wensite, they use the existing stringewrs..Its just the idea od after pulling all that wet foam out , then putting it back in...You are "right" on about the stringer attachment to the hull..there is only one layer of cloth or mat attaching it to the hull..It seems if they have put a couple layes and tabed it more than 3 inched it would have held...Have to make a decision..guess I'll be re thinking this again....Thanks

[Capt Matt]

I could not bring myself to refoam the stringers after removing all that wet foam. I started out with the intention of repairing the old stringers. I needed to raise my floor and felt attaching any thing to the 40 plus year old stringers was not as structurally sound as building new. Your boat being only two stringers wide would be a lot less work than my flatback being 5 pyramid stringers wide.
Capt Matt

[dirtwheelsfl]

like said before, the foam core itself isnt doing much of the work, its in the vertical faces of the glass thats on them. you can butt joint foam core together with epoxy and the foam itself will rip off before the epoxy bond between them fails (in most cases). youre going to be doing alot of grinding and tabbing either way if you retab the original stringers or making new ones. making new ones wouldnt be that much more work. i was able to get both stringers and all bulkheads out of 2 sheets of 1" corecell. 2 layers or 1708 on each side, then 2 wrapping them, then 2 (12" and 10") tabbing into the hull. only about 40# apiece. just another one of the many options to consider...

[305kingfisher1954]

Yes Rick,  Lobster traps and some stone crab traps too..I'm working in a little fishing village in the Florida Keys..

[RickK]

I could not bring myself to refoam the stringers after removing all that wet foam. I started out with the intention of repairing the old stringers. I needed to raise my floor and felt attaching any thing to the 40 plus year old stringers was not as structurally sound as building new. Your boat being only two stringers wide would be a lot less work than my flatback being 5 pyramid stringers wide.
Capt Matt

Do you find the hull to be real noisy without any foam for sound-deadening?

[gran398]

Some thoughts on today's discussion. Just returned from the boat shop, thinking rebuilds, so:

Matt has a flatback. Entirely different original stringer system than the later 12 degree 22-2's, which had only two large trapezoid stringers.  Matt, I can see with your classic flatback why you would have scrapped what was existing. There is no doubt that what you have built is substantially stronger and stiffer than the original.

Slip, as you recommend, on my '73 we went with the original double trapezoid stringers. Glassed permalloy high density synthentic tops, which in retrospect was a waste of money and weight, since we are now installing a pulled, molded, nidacore floor system to accommodate a removable tank hatch. The original plan was to tie the console to the stringers. Now the console will be tied to imbedded permalloy in the deck core in the console outline area.

Regarding tabbing the existing trap stringers, their present survivability probably depends on original layup quality/cure/ass-whipping through the years. From former reports here...when the plywood floors are cut away...the stringers are mostly good/fully intact. The ones on Miss Delmarva were great. We cleaned up the tabs, added more glass anyway.

Been some recent discussion re tank hatches...some want them, some don't. I was with the latter group initially. But, after talking with friends, decided to invest the extra money to be able to inspect the entire tank down the road. Figured since am planning on keeping her the rest of my life...money well spent. Not a quick and easy job. An entire deck mold was built incorporating a tank hatch...plus molded recesses for the floor hatches.

Because we changed mid-stream from a completely closed deck to a tank hatch...builder says the biggest regret he has is that we should have saved EVERYTHING from the original floor, other than of course the plywood. Could have re-cored the female/male portions of the tank hatch area. The liner could have also been saved and reused...yet glued to the hull-sides unlike the unattached original.

Guess the point being...plans can change. So on the demolition, spend a little extra time on your cuts with regard to the future...whether you use the parts or not.  If nothing else, could be a resale opportunity.

We will place sheet foam outboard of the stringers for sound deadening.

[RickK]

Yes Rick,  Lobster traps and some stone crab traps too..I'm working in a little fishing village in the Florida Keys..

Would not have thought you were in the keys and was thinking some place up north, hence the "lobsta" question.

[Capt Matt]

Rick
My hull is real quiet without the foam, Nothing vibrates even when running and it does not have that hollow sound to it. Probably because everything is stuck together and locked together.  
Capt Matt

[305kingfisher1954]

Making a little progress this week..cap is ready for new foam core...

Removing core from casting deck..Plan on insulating port and starboad deck boxes to hold ice...

Got her turn over today to prepare for new gelcoat bottom...hope to spray gelcoat friday afternoon..First and last time I sanded bottom paint...NASTY job...will sandblast for sure next time...

[dirtwheelsfl]

looking good, you down on stock island?