More like a Briar Patch

I am getting back on the BFN. I HATE grinding.
I climb out that boat looking like a powdered doughnut.

Oh man...what a truely horrible association to put with 1 of my favorite junkfoods?!!? LOL

Looks like you're at the easy part now; and I am strangely envious! Thanks again for your help on mine.

its the same concept as where you were at when JFK was shot, its something you wont forget, recently,after 2 weeks my finger got so purple and festured that i grabbed the razor and started cutting, I picked, i probed and finally discovered the 1/4" piece of glass.....wear gloves

"What'd you say? Oh that...it'll grow back"?!!?     

Looking really great BJ.. Eric is right on with the gloves... And I to remember that gouge to the leg...

How about wearing some long pants too.

john

I had a good day today. I fabricated the new composite stringers to the 81 BFN. They are constructed of two layers of Divinycell H-80 5/8" (5 pound density), sandwiching two layers of 1.5 ounce glass mat in between.
   Over the last week I laid up four 12 ft. strips of 24 oz.roven woven 12" wide along the length of the hull. Next, I am going to reconstruct the transom/lifting ring assembly.
When i can set time aside to work on this project I get pumped up.
bj

I have a photo of three of the four strips I will post. But as a better description, the strips are to strengthen/reinforce the bottom of the hull. They run from the transom forward 12', (overlapping of course.)

It is a little difficult to discern but there are three of the four strips as previously described, Two on the left one on the right. This was added to beef up the hull.

Somthing the original boat did not have in 81 is an aluminum engine cradle that will be added this time around

I also get a bang out of going back to look at what it looked like before hand.

Hasbeen - Interesting choice of materials for your stringers. Has anyone ever used this before? I assume the epoxy will not adhere directly to the PVC substrate - how will you tie all your glass layers together for torsional rigidity?

Also - what will your engine mount lag screw threads bite into?

Good luck with your project. I can only add that sticking with a traditional wood core / epoxy resin construction would give you some legal protection in the future, as it is well tested. If you use an untested design & it fails, you could be liable for any resulting property damage or injuries. When you go to sell this boat, please disclose your construction to the prospective buyers.

hasbeenskier wrote: Thanks, Comosites are not experimental at all. You may know the better boat builders don't use wood anymore but, composites. The boat will be over built and better than original. bj

The composite may not be considered experimental but when you follow the same stringer design, eliminate the structural strength of the wood and rely solely on the glass covering of the new "stringer" it certainly becomes experimental. The composite in todays boat construction doesn't follow the same shape as our old boat stringer system.

When Joe did his boat with the Coosa board, he carefully researched the structural modulus. All Chris is saying and I'm agreeing with is be careful. A boat repairer is not the same as a boat manufacturer. Did you ask him about any failures?

Bj,
I'm glad you're counting on the glass around the H-80 and you had better be laying LOTS of it around the stuff!! This is especially true because you're using polyester and not epoxy resin. I was curious and looked up the specs. It's not much better than a wet noodle but at least it won't rot!

Ultimate tensile strength - MPa
Fir - 130
H-80 - 2.20

Tensile modulus - GPa
Fir - 11
H-80 - .08

Shear modulus - GPa
Fir - 4.1
H-80 - .0309

You have lost lots of strength without the Doug fir. Did you ever even look at the specs? Hopefully you're not just "winging" this project. Is Gary Baker a engineer (hopefully structural/marine).