Ski Nautique stringer replacement

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
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Ski Nautique stringer replacement

Post by DAYTRIP »

Jaques,

Replacing the stringers on my Ski Nautique and have built as mold and laid up hollow sections. There are two main stringers and two outboard secondary stringers. Looking at the lay up for the LB 26 it looks like 6 layers (3 each side) of biax over foam. Any thoughts on how many layers if they are hollow? They have a maximum height of 6.5". I will core them in the area of the engine mounts for crushing/compression strength for bolting.I was thinking of urethane foam filling them for noise and I think it will help with cripling resisitance.

Thanks,
Jim
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Post by tech_support »

The LB26 stringer would be made using divinycell, so your getting the effects of a sandwich where the core is structural.

for hollow stringers (or stringers filled with non structural pour foam), you need to build thickness. On a boat that size a hollow stringer will have walls about 3/16" thick. Thats about the thickness of the old Aquasport trapezoid stringers. The shape is also important, i would make the wider, maybe 3" at the top.

If you want them to be tall and narrow, then you should use a core (wood or divinycell)

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Re: Ski Nautique stringer replacement

Post by DAYTRIP »

Making some progress. New stringers and bulkheads made of glass.

This is the mold I made for the stringers. Two pieces of MDF with gloss mica on both side. Edges rounded over.
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This is after lots of grinding. Stringers are jiged into place
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All Glassed in here
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This photo shows an area that I will be using for fresh water storage
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Building this like a salt water boat.No carpet, awlgrip inside and out just like my barefoot nautique.
Last edited by DAYTRIP on Thu Aug 20, 2009 8:21 pm, edited 1 time in total.

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Re: Ski Nautique stringer replacement

Post by tech_support »

Looks good. Nice hollow glass stringers.

So is the water storage for ballast?

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Re: Ski Nautique stringer replacement

Post by Chief Brody »

LOL LOL.....thats awesome......the work is great, but the comment from Joel is awesome....

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Re: Ski Nautique stringer replacement

Post by Cracker Larry »

Chief, it's not a joke. The Ski Nautique is a competition ski boat, and they use water tanks for ballast to control the size of their wakes. Different types of skiing/ wakeboarding competitions require different wake sizes and locations (distance from the boat). It's controlled with ballast tanks.
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Re: Ski Nautique stringer replacement

Post by Chief Brody »

Cracker Larry...yeah I know about ski nautiques as a water ski boat.......pulled my big butt around a pond more than once....its the water tank comment with the stringers I chuckled at....I don't think the stringers were designed to be water tanks....unless I missed the joke....which wouldn't be the first time.....

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Re: Ski Nautique stringer replacement

Post by Cracker Larry »

The hollow stringers are called top hat stringers. Made hollow for a reason and it isn't ballast. Doesn't have anything to do with the ballast tanks.
unless I missed the joke
Chief, it's not a joke.
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Re: Ski Nautique stringer replacement

Post by Chief Brody »

I know, exactly...I've seen them before.....thats what I thought he was referring to.....I did not see any other "ballast" in the picture....it really doesn't matter...

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Re: Ski Nautique stringer replacement

Post by DAYTRIP »

Thanks Guys, the water will be held in the void between stringers and the the bulkheads (not in the stringers themselves). In my case it is for fresh water wash down but could be used for some wake ballasting. It is only about 12 gallons so not enough to do what most do with ballast. I am more concerned about washing the salt off my body than jumping wakes at this point. My kids may see it differently.

Thanks for the comments!

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