1970 22'2 FLATBACK REBUILD

[LilRichard]

Rick - appreciate your feedback.  However I am compelled to answer this topic, because I do not understand where I have criticized his work or for that matter been anything other than pleasant in this exchange - contrary to what is being said.  I did ask how he reglassed the tops of his stringers and made the point that this was a very important step - not one to be taken lightly.  Am I going nuts here guys?  

Slippery - If people are going to post pictures and processes in a boat rebuilding forum, do you expect folks to not ask why something was done a certain way, or not speak up if they think something was not done properly?  I know all my work is not perfect, and I have had people point out my mistakes, and that's how I learn.  IMHO, simply saying "oh sure, should be fine" does not necessarily help someone improve.  Fact is, I never GOT an answer to how this was completed, so I never even got a chance to understand his work.  

I am sorry you took it personally, especially after stating that was not my intention.  I implore you to find one negative comment here by me in over 900 posts...

[slippery73]

I didn't take anything personally. I understood what was done by reading the posts. It was clear to me, perhaps thats why I was wondering what you were asking. I apologize for the misunderstanding, however in the future you may want to use a little more tact when it comes to asking these types of questions. That way you dont come off being so abrasive, its more encouraging for our new members to learn and move forward. Nobody, and I mean nobody likes to hear that they did something wrong. Not saying it shouldn't be pointed out if there are mistakes, but that doesn't mean just because its not how you did things its the only way. Simply saying a few respectful questions rather than implying doubt to someones work goes a lot further.

[Shine]

HPerhaps Shine used carbon fiber on the stringer caps to compensate for the lack of size of the original stringers.
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The trapezoidal glass stringers are a wonderful design, the fact is my AS did not have them when I bought it (had be re-built once before) - so I was forced to chose a more traditional structure of stringers and floor frames.

I use the uni-direction carbon to cap the stringers because it has equal stiffness of perhaps 5 time that of equal weight fiberglass - I saved weight.

1" thick Divinycell cored stringers made with all biax and epoxy would be strong enough for a much bigger boat.  the lamination schedule for the stringers is more than adequate

Nobody, and I mean nobody likes to hear that they did something wrong.

I agree :)

Thats not what I would consider "over building."  
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please explain how my structural design is deficient

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From what I read here Richard was concerned that someone simply plugging holes in the top of the stringers.  His wanted to making sure the holes were patched in a way to ensure they were as strong as before.  That is a true concern as that the strength of those stringers come from the fiberglass.

the foam in the trapezoidal stringers is not structural - the thickness and shape of the trapezoid give them stiffness.   Does filling some shape with some 2 lb. pour foam add stiffness - yes to some extent, but it would never be relied upon in the design of the boat, if it did all these boats would not have held together as long.  

PU foam does not have the peel and shear properties (forces you see a lot of in a stringer) to act as a core in a true composite sandwich (at least in the densities you get from pouring, in very high density around 20lb it is almost as strong as 5 lb Divinycell foam - at 4 times the weight!)

however in the future you may want to use a little more tact when it comes to asking these types of questions.

again, I agree :)

[slippery73]

Shine, I wasn't insinuating that your stringer design was deficient in any way. As I said before your motives behind using the carbon fiber on the top cap were probably because the stringers you built weren't near the size of the original stringers. This would warrant additional build up of glass, or stronger materials, ie. carbon fiber. It would also warrant the full width bulkheads as well to help with torsional stresses, all of which you did. Quite well I will say also. My original point here was that foam, albeit even two part foam does add structural rigidity. Im not saying that it is a crucial design element of these boats, but im sure it helps. Its amazing how strong simple foam sandwich construction is. I've done scientific structural testing on all of the structure types listed in a laboratory, and it really is incredible how strong something becomes when engineered properly.
As a side note, the original stringer design is one of the strongest all around designs you could have in a boat. The trapezoidal design is also used in segmented concrete bridge construction because of its strength characteristics.

[wysongja]

I/2 in marine ply cut to slide into place under the cap and attach to the (2) 34 inch transom


pre fiberglass transom with compound
   
Ready for glass

Glass in....sanding and skimming begins

[wysongja]

From bow

Close up on in floor fish box......our fuel tank is going under front platform..

Close up of new transom cap..Center box to hide lines and bolts with benches on either side over future dual bait wells.  Center cap strong enough to stand on and spot bait...etc.....Above floor bilge in case of bathtub(also will have two large scuppers) and second below floor bilge..

[LilRichard]

wysongja-

Can you post some more pics please?

Did you completely cut out the old transom?

[wysongja]

After you brought up the issue of glassing over the body paint we were concerned with the previous work.  We removed all the old glass and resin but the ply seemed to be done correctly.  We added the piece to complete the full transom.  We added another 1/2 in marine to the inside that came up over the added seem.  So our transom actually has 2" of plywood before glass.  What other pictures would you like?

[LilRichard]

Makes sense.  I was looking for a shot form the rear (side) to see how you glassed the new glass over the hullsides.

[wysongja]

Question about hatches.  The hatches that were used by hammerhead boat works on the front platform, Were they purchased or made?  I have been looking around for a decent hatch and want to stay away from plastic hatches that sit above the floor.  I like the look and durability of the flush mount fiberglass hatches, I guess my question is are fabricated or purchased?  And if they are fabricated how is it done?  Is it time consuming?  How large or a span can they handle?  Please help.

[LilRichard]

Hammerhead (Tommy) makes his own hatches - he has molds.  Starting from scratch is not terribly easy - look at Shine's project for details.  I used a mold to build mine - not terribly difficult.

On the other hand, you can buy some from Young's boatworks - that's where Capt Rick got his.

[wysongja]

Do you have any contact info for Young's?

[LilRichard]

http://young-boats.com/

[wysongja]

It has been a while since our last post and we have been doing some good production.  Our floor has been screwed and glued and we have two coats of glass on so far.  All wiring and fill tubes have been run and our fuel tank is operational.  We could not find a center console that we really liked so we decided to make our own.  I think it really turned out well, we cut a cooler in half and foamed it in the front.  We wanted something around 28" wide but with enough height to handle a leaning post.  After making the console we decided to make the leaning post baitwell as well.  It has a 35 gallon circular tank from betterbaitwell.com and we built the leaning post around it.  Still have some work to do on the cap and finish the seating across the transom.  Only 45 more days to have her in the water, going for a new land speed record.  Wish us luck.  House in the keys 7/19/08.  Here are the most recent pics.





   
 

[scott_gunn]

I like the layout of the new console and baitwell.  Good job!