Ski Nautique stringer replacement

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
DAYTRIP
* Bateau Builder *
* Bateau Builder *
Posts: 790
Joined: Wed May 31, 2006 10:32 pm
Location: North Palm Beach
Location: NORTH PALM BEACH

Ski Nautique stringer replacement

Post by DAYTRIP » Wed Nov 19, 2008 9:40 pm

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
Image,Image,



User avatar
tech_support
Very Active Poster
Very Active Poster
Posts: 12319
Joined: Wed Dec 31, 1969 7:00 pm
Location: Vero Beach, FL
Contact:

Post by tech_support » Mon Nov 24, 2008 10:02 am

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)

DAYTRIP
* Bateau Builder *
* Bateau Builder *
Posts: 790
Joined: Wed May 31, 2006 10:32 pm
Location: North Palm Beach
Location: NORTH PALM BEACH

Re: Ski Nautique stringer replacement

Post by DAYTRIP » Wed Aug 19, 2009 10:13 pm

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.
Image
This is after lots of grinding. Stringers are jiged into place
Image

Image
All Glassed in here
Image

This photo shows an area that I will be using for fresh water storage
Image

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.

User avatar
tech_support
Very Active Poster
Very Active Poster
Posts: 12319
Joined: Wed Dec 31, 1969 7:00 pm
Location: Vero Beach, FL
Contact:

Re: Ski Nautique stringer replacement

Post by tech_support » Thu Aug 20, 2009 10:59 am

Looks good. Nice hollow glass stringers.

So is the water storage for ballast?

Chief Brody
Very Active Poster
Very Active Poster
Posts: 542
Joined: Wed Jun 24, 2009 3:46 pm

Re: Ski Nautique stringer replacement

Post by Chief Brody » Thu Aug 20, 2009 8:28 pm

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

User avatar
Cracker Larry
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 22480
Joined: Fri Mar 11, 2005 3:39 pm
Location: Savannah, GA

Re: Ski Nautique stringer replacement

Post by Cracker Larry » Thu Aug 20, 2009 10:32 pm

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.
Completed GF12 X 2, GF16, OD18, FS18, GF5, GF18, CL6
"Ships are the nearest things to dreams that hands have ever made." -Robert N. Rose

Chief Brody
Very Active Poster
Very Active Poster
Posts: 542
Joined: Wed Jun 24, 2009 3:46 pm

Re: Ski Nautique stringer replacement

Post by Chief Brody » Thu Aug 20, 2009 10:42 pm

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.....

User avatar
Cracker Larry
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 22480
Joined: Fri Mar 11, 2005 3:39 pm
Location: Savannah, GA

Re: Ski Nautique stringer replacement

Post by Cracker Larry » Thu Aug 20, 2009 10:52 pm

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.
Completed GF12 X 2, GF16, OD18, FS18, GF5, GF18, CL6
"Ships are the nearest things to dreams that hands have ever made." -Robert N. Rose

Chief Brody
Very Active Poster
Very Active Poster
Posts: 542
Joined: Wed Jun 24, 2009 3:46 pm

Re: Ski Nautique stringer replacement

Post by Chief Brody » Thu Aug 20, 2009 11:00 pm

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...

DAYTRIP
* Bateau Builder *
* Bateau Builder *
Posts: 790
Joined: Wed May 31, 2006 10:32 pm
Location: North Palm Beach
Location: NORTH PALM BEACH

Re: Ski Nautique stringer replacement

Post by DAYTRIP » Fri Aug 21, 2009 6:59 am

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!

Locked

Who is online

Users browsing this forum: No registered users and 8 guests