Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

son of a son of a sailor

Seaman Apprentice
Joined
Apr 15, 2010
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33
Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

So I have done allot of reading and a fallowing on ibaots, and now it's my time to pick at those amazing brains that are out there. I own, and am repairing, a 1969 Glaspar Citation. (Similar, if not the same boat as "headhunter2", you can see all his work under this restore forum or just by typing is screen name in the search box). I have also read every page and continue to fallow the amazing progress of "drewpster" and his tri-hull. SO, now I'm getting ready to break out the camera and start working on my project.

I feel I have all the transom and deck information I need. The only uncharted area I feel an bit uninformed is my plan for stringers. My concern is with the strength of the hull roving and if I need to add any additional support under my stringers (such as a strip if 18oz. under where the stringers will be applying pressure/force.

I am familiar and am comfortable with allowing these stringers to "float" over a bed of thickened epoxy to create an expanded area for the 1 1/2" stringer to apply force/pressure. Again, just wanting to know the thoughts on how wide I might want to go or if I need to reinforce the hull with a strip of 18oz. or more roving.

If you are not familiar with the glasspar stringer system for the citation model you can see how headhunter2 re-did his with foam. My only concern with this is that, ultimately this foam will soak water and become a water clogged, weighted mess, and have to be pulled out (major pain in the a**)

My thoughts are to replace these foam stringers with ridged ones, cutting, shaping, and filling the voids with ridged pink insulation foam that does not absorb water. I realize that this foam cannot be laminated and all resin/laminates must be dry by the time this is install.

Thank you to all that have read this and I appreciate and feedback you might have.

-sfsf
 

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Yacht Dr.

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Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Hello SFSF..and welcome to Iboats..

Yea the stringer system ( floating or non-floating ) is a boat to boat thing..

Lets say you have a 180 with a low profile stringer..yup..I would hard bed those stringers/bulks and glass over..

Now lets say you have a 30+ with long rigid bulks/stringer integrated..with big open pans .. then I say float the stringers..

It really all depends on how the boat was made ( and you would have to determine if the stringer/bulk system is correct for said boat..because some boats are Crazy leaving Open pans in the hull when they should have a support bulkhead here and there ).

I suggest there is no Right way of Every boat size and shape on how you String your boat.

I would say that if you Dont Prep your glass and seat your stringers/bulks then your putting carpet over cow dung..

You..WE..All of us KNOW when your grinding to replace Bad glass..or repair..you HAVE to replace Bad glass..( now Alum..talk to BobVT or Bondo..or someone else .. not me on alum repairs )...

Glass .. yes..But pics mostly does not show up untill the glass is done.. ( basically nobody wants to show what they glassed too LOL ).

I digress..

YD.
 

SawDust{RM}

Petty Officer 3rd Class
Joined
Nov 30, 2010
Messages
83
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

You should check out composites if you haven't already
 

son of a son of a sailor

Seaman Apprentice
Joined
Apr 15, 2010
Messages
33
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

You should check out composites if you haven't already

I was thinking of pouring in place my stringers (out of Nida-core or SeaCast) but the cost just got to crazy for the age and scope of this boat. I even tossed around the idea of a product I use as a residential carpenter call AZEK. It is a great exterior trim product but will not cooperate with poly resins. The final one I thought of was using honey comb panels, and again.... cost just got in the way. You wouldn't have any info on creating a nonslip/slid deck coverings would you? Thinking about using some type of high UV resistant paint, mixed in with either sand or a composite compound.
Thanks,
SoSoS
 

son of a son of a sailor

Seaman Apprentice
Joined
Apr 15, 2010
Messages
33
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

yd,
This is only a 1969, 16.5' run-about. Great for the pudget sound a surrounding lakes. Great for fish, fun and getting some sun. I just don't feel like scrapping out the stringers if they get full of water again. If you haven't checked out headhunter2 you should see the pour in place foam. It's crazy how fast this stuff expands. Only problem is that the foam sucks water like a sponge. (I'm sure you already know this). Anyway, thanks for the encouragement.
SoSoS.
 

SawDust{RM}

Petty Officer 3rd Class
Joined
Nov 30, 2010
Messages
83
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Now that I'm getting older I can't stand to get in these newer boats with the slick as snot floors, I was in a boat that had gel coated floors with sand added, it felt terrible on your feet. lol
Theres alot of different products to use for a good feel to the Deck, I've seen posted before
here's a link for Durabak
http://www.nonslipcoating.com/
 

nymack66

Petty Officer 1st Class
Joined
Aug 5, 2009
Messages
356
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

You may want to consider a Urethane two-part liquid, expanding rigid urethane foam is a closed cell, pourable foam, which will resist the absorption of water.
http://www.uscomposites.com/foam.html
 

Peteco

Seaman Apprentice
Joined
Aug 12, 2009
Messages
36
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

I realize that this foam cannot be laminated and all resin/laminates must be dry by the time this is install.

You can laminate over foam, but you need to use an epoxy matrix resin. Structurally you'll be fine if you use the right layup schedule, I've built a wing spar on an airplane with foam, fiberglass, and epoxy. Also, you can't use CSM with epoxy (unless it's special CSM with binders intended for epoxy use).

I know that plywood/polyester/CSM is used on most boat work, but this is probably a function of costs more than anything. There is nothing wrong with making sandwich structure with foam, since the core is only really a shear web for the sandwich. That being said, I'm going to go with plywood for my floor since (1) it's cheaper than foam/epoxy, (2) weight is not an issue so the heavy core doesn't penalize me, and (3) I don't want to spend the time to remove the foam core to create the various hardpoints I'll need.

Certain urethane foams are compatible with polyester resin, maybe all of them. I'm unsure on that though. Urethanes are kind of crumbly and nasty to deal with, and they can't be hot wired however (toxic fumes).
 

headhunter2

Seaman Apprentice
Joined
Aug 18, 2009
Messages
44
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

I thought I would post on here, was thinking about you the other day and looked to see where you were at. Just to let you and anyone else looking know how my job turned out all looks great. I have had the boat out over 50 times on the sound, in some rough stuff several times and she is holding up great. Much quieter and planes out faster than prior to the overhual. With your water concerncs if you go foam jus make sure you seal up all access points for water to enter, thats what i made sure of because believe me I do not want to do this job again. Good luck sailor...
 

son of a son of a sailor

Seaman Apprentice
Joined
Apr 15, 2010
Messages
33
Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

Re: Replacing foam stringers with "ridged" laminated wood stringers. Any suggestion?

I thought I would post on here, was thinking about you the other day and looked to see where you were at. Just to let you and anyone else looking know how my job turned out all looks great. I have had the boat out over 50 times on the sound, in some rough stuff several times and she is holding up great. Much quieter and planes out faster than prior to the overhual. With your water concerncs if you go foam jus make sure you seal up all access points for water to enter, thats what i made sure of because believe me I do not want to do this job again. Good luck sailor...

Hey! Good to hear from you. Was wondering where you got that foam that you used and if it was a urethane based product or not. I'll check your project post again and send you a message.
 
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