new 222 rebuild

[Shine]

Divinycell is PVC foam specifically made to be core in composite construction, H80 is the 5 lb density.  There are 2 ways to make foam stringers.  In this method, the foam is part of the structure and it is important what sort you use.  The other way is make the foam just a form to lay glass over.  But you need much more glass and it ends up being heavier.

When I mentioned "tabbing" I mean the 3 layers of 6" biaxial glass tape that joins the stringer to the hull.  There is a 1/2" radius fillet under the glass, it make the transition smooth and much stronger than without a fillet.

A trick to getting super clean laminations is to work "wet on wet".  For example: make the fillet, then only after 10 minutes or so (while its still soft)  lay the first layer of tape onto the fillet.  Now when you wet out the tape with more epoxy, the filet and the glass blend in and cure together.  The subsequent layers of tape are laid on there after.  Also, you end up using less epoxy this because any extra epoxy from one layer helps to wet out the next - less waste

Thanks for the old picturess, pretty cool

[warthog5]

Raw Devenicell.



http://www.classicmako.com/projects/xshark/bw14.htm

[Shine]

The hull is getting new glass     Below we show 50 oz. of new fiberglass one one side of the boat.  Its 2 layers of 1708 with epoxy.  We will hopefully get the rest of the bottom glassed next week.  

It took hours of grinding to remove the "repair" layers of glass.  The previous repair was done with polyester and mat, they just slopped it in.  There were water filled voids every where, also huge pools of plain resin.  The 7" grinder with 24 grit disk made it a little easier vs. the old 4.5" grinder.

It was easy to tell when we ground down to the original 30+ year old glass, as it was much better.

[RickK]

Have you decided whether you are going to fill the bilge with foam or leave her empty? Looks great!!

[JimCt]

Very, very nice work.
 Whose epoxy are you using?

[Shine]

Im sure the moderators are sensative to their forums being used to advertise products, so I wont do it intentionally.  

But the epoxy is our brand, Marinepoxy.

[Shine]

More glass on the bottom between stringers, also filled in the space that is the keel – filled with foam and glassed right over it.  Next will come the uni-directional carbon fiber for the cap of the stringer.  We will use a much stiffer epoxy for the carbon fiber.

If anyone want to come by and help remove the rest of the old cap and sole, let me know.  Im not looking forward to the last of the demo work :evil:

[LilRichard]

You're going to use carbon fiber?  Seems like overkill, so curious why you think it is necessary?

[Shine]

The stringers need to be capped, I can save some weight by going with the CF over glass.    I can use less (weight) of CF  vs. using glass.  So I get the same stiffness with less weight.

Plus, I have CF that Im not using on anything else, it not doing much good on the shelf.

[LilRichard]

Plus, I have CF that Im not using on anything else, it not doing much good on the shelf.

The truth comes out!  I wish I had material just laying around...

Question (on material):  I was at FGCI on thursday talking to one of their knowledgable sales guys... and he recommended using 2 layers of 2415 stitchmat versus 3 layers of 1808XM when building my stringers.  He explained that the 2415 will add more total thickness, thus more stiffness than 1808.  He conceeded that 1808 is stronger where there will be more flexing (like in the hull), but that the additional thickness from more material would be beneficial in a stringer layup.

Agree, disagree?  I would rather do less lamination than more, but don't want to skimp either.

[JimCt]

Based on the stringer detachment problems in my 240, I'd say the greatest stress to the stringer grid is at the lines of attachment to the hull.  I've beefed up these areas with four layers of stichmat laminated over generous fillets.  This also is important if you will be transporting the boat on a roller trailer, as I will be, since the rollers support the hull only at descrete points.  A bunk trailer minimizes the stresses considerably by distributing the load over a much larger area.  The extra glass adds a few pounds but the peace of mind is worth it.

[LilRichard]

Jim- why not just set your trailer up with bunks?

And I just think they did a crappy job of attatching the stringers in the first place- mine were not attached at all.

Good thoughts though- thanks.

[warthog5]

Jim- why not just set your trailer up with bunks?

And I just think they did a crappy job of attatching the stringers in the first place- mine were not attached at all.

Good thoughts though- thanks.

LilRichard  Here in lie's the diffrence in Fl and new england area and the reason for a roller trailer up north.

It's the tide's.

We get a average tide of 1ft to 1 1/2ft  rise and fall.  They get as much as 8ft or more up there.

Then you have a set length of the boat ramp and need to unload shallower. So you need the roller trailer up there. This is also the reason you see a lot of power winch's on trailer's up there.
here we just drive it on the trailer.

 

[LilRichard]

I never knew that- thanks for enlightening me...

I think I would hate having to tie up a boat with that kind of varying water level.

[Tim/GA]

Here in GA our tides average 7ft between high and low on neap tides and regularly reach 9 1/2ft difference on spring tides.  I would say that bunks outnumber rollers around here on all but the biggest boats.  It does mean you have to know your ramps and at times have to dip the trailer in farther to load the boat.  Slick bunks can help as long as you don't launch the boat on the dry ramp.