Saturday, July 11, 2009

Batboat Rebuild: Day 29 July 4, 2009

It was a happy Independence Day for me. I started the long process of getting the stringers ready to bed into the hull.

Stringers are important structural components to boat building. One of their functions is to have a solid place to screw the deck on.

Decks for boats like mine are generally made out of several 4 foot sheets that butt against each other for the length of the hull. To add strength and prevent the board ends from moving, cross braces are mounted in across the stringers. The deck sections screw down to them for stability.

One of the issues with the way my particular boat was made is that the notches for these braces created weak areas in the stringers. The smallest stringers were reduced to 3/4 inch in height.

Nearly all of those spots on the original stringers were broke and rotted. To compensate I designed braces that both add strength for the stringers and cross braces.

Also, the original cross braces were about 2 inches wide. The ones I'm putting in are 6 inches.

It took nearly all day to get it right and the results were great.

During the week I cut the marine grade cross brace braces into the shapes I needed. Today came the notches for those and the stringers. It took a long time to do this with my table saw.

Four of these braces will also join the sections of the longest stringers together. Marine Grade Douglas Fur Plywood comes in 4 foot by 8 foot sheets in this area, the two longest stringers in the Batboat are about 12 foot. So I have 8 foot pieces that the brace braces will join to their other ends, as shown above.

Stringer halves gets are joined and braced on each side of the cross brace notch.

The smaller stringers really need extra help as you can see above. The notch reduces them to less than 3/4 inch by 3/4 inch in that area. However, the braces will give them a total of 2 1/4 inch of strength in width.

The stringers seeme much more stronger and cross braces are more better positioned with the added braces.

The plan is to laminate all of the braces to the stringers with fiberglass, add stainless steel screws for added stability and lay fiberglass over that to waterproof the screw heads.

On this day I began fiberglassing the braces to the stringers. I have one set of saw horses so this took forever. One set of stringers at a time, one side at a time. It was a few days before I finished it all. The results, however, are very nice.

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