Adding strings to a boat without stringers

[NissanOutboard]

Hi guys,

I’ve got a 14 foot skiff/fiber glass Jon boat that I’ve been working on. I have a 25hp on it.

I have taken it out a couple times and at higher speeds 20+ mph the hull will flex in the middle. My thought is if I put in a stringer or 3 it should solve for the problem. I wanted to post some pictures and ask, do you think it’s a good idea to put stingers and a false floor in to help with the flex?

Also where should I place the stringers?

Thanks

 

[GSX455]

The hull looks shallow, but you could put at least 2 stringers about 2-3" tall in those grooves. What material do yu think the hull is? If its not fiber glass but plastic you will have a hard time bonding to that. You would use marine grade or CDX plywood, cut the stringers to match the shape of the grooves and maintain a consistent deck height; glue them in with a mixture of polyester resin, fumed silica and chopped glass fiber. Roughly 20% by weight each for the fiber and fumed silica and add that to resin until you get something the consistency of peanut butter, that's how it get its nickname. Make sure to sand the hull well so it adheres to the hull, and rinse with acetone before bonding. Good luck.

 

[NissanOutboard]

Thanks for your feedback. The hull is made out of Chopper Gun fiberglass. The hull is actually a lot deeper than the picture makes it look.

If I was going to go with just two stringers which groves would you recommend putting them in? Or should I just go for 3 stringers?

 

[NissanOutboard]

Also if I put stringers in how should I go about a proper drainage system?

 

[GSX455]

Also if I put stringers in how should I go about a proper drainage system?

Before I put a hole in the hull, make sure you find if polyester or 3M 5200 sticks to the hull material. A brass Gabbard plug will ensure a leak free fitting to your boat, or you can use a brass drain tube with rubber plug. https://www.westmarine.com/moeller-1-1-4inch-brass-drain-tube-14567960.html
3M 5200 is permanent, it is strong but brittle. 1&1/4" hole big enough for a brass tube would do the trick, but test a marine adhesive like 5200 first to make sure it sticks and the bond will hold