shaping boat stringers

[Smokin'Mo]

I need someones expertise in stringer construction and I know this is the right place after reading some of your posts. You guys know your s**t.
How are stringers shaped to match the contour of the hull. I am about to install new stringers on my 21' fg boat and have thought of several ways to do this, each one more difficult than the last. How crucial is it that the stringers match the hull contour perfectly? if it's not, will some of the imperfection be removed when it's seated into the resin/matt mixure applied to the hull?

So far the best way seemed to be running string lines along the length of the old stringers at the upper corners, bow to stern (I marked these locations before I removed stringers) and then measure down to the hull using a level to be perfectly vertical creating a profile of the hull in 6" increments along the stringer length.

Any easier way???

 

[Chinewalker]

Re: shaping boat stringers

Get it close - your peanut butter epoxy will do the rest... A beltsander with a 40 or 60 grit belt is your friend and can make quick work of minor adjustments to get the stringers fitted...
- Scott

 

[SgtMaj]

Re: shaping boat stringers

If your old stringers came out in one piece you can use them as a template to get you close.

 

[Bondo]

Re: shaping boat stringers

So far the best way seemed to be running string lines along the length of the old stringers at the upper corners, bow to stern (I marked these locations before I removed stringers) and then measure down to the hull using a level to be perfectly vertical creating a profile of the hull in 6" increments along the stringer length.

Ayuh,......... That's what I'd do......

 

[tashasdaddy]

Re: shaping boat stringers

then get a refrigerator box, cut it up, do you layout on the card board, cut it out and test fit. cardboard is a lot cheaper than lumber.

 

[Hoserpoppasmurf]

Re: shaping boat stringers

I did mine last winter. I rough shaped the stringer, then screwed/blocked them an even height above final bed-used compass/pencil off bottom of hull to loft the line on to stringer. Big trick though-keep bottom true, without stringers it becomes easier to warp or get a hook into the bottom- not a good feature for handling. As stated-belt sander makes good beaver.

 

[Smokin'Mo]

Re: shaping boat stringers

Thanks for the advise guys. I just finished laminating the first stringer - 2" thick (like the original), 1/2" outer skins & 4 inner 1/4" pieces all glued together. After I'm done building all 4, I will transfer the measured points onto each side, cut out with jigsaw and belt sand the rest.

 

[BillP]

Re: shaping boat stringers

You have the right idea for measuring. I do it that way and transfer it directly to the stringer for cutting. No templates needed and only requires minor trimming to fit. Floors are done similar with a centerline on 12" stations. Here's a pic showing measurement for a center stringer.