Stringer Replacement 86 Silver Nautique.

This is the stringer layout for my boat.  The old stringers where likely cut from a standard pattern but I’m not sure how tight they followed the pattern.  I expect each boat varies a little based on what I’ve seen on this boat.  Best if you use your stringers to layout your new stringers.  But if you can’t use your stringers, this should get you pretty close for boats like mine.

Top of the page is a plan view (looking down) of the secondary stringer, the space for the exhaust hose and the top of the main stringer.  The circles are bolt holes in the aluminum engine frame.

Below that is a side view of the stringer showing the dips, their locations and depths.  The gas tank is shown at + ½” because the floor is a ½” thick and the two aluminum angles under the tank sit basically flush with the top of the floor, making the bottom of the gas tank maybe a ¼” above the floor.  0” elevation is the underside of the floor.  Everything is measured from the transom of the boat in line with the thing you are laying out, keeping in mind that the main stringer hits the transom is a bit further aft than the secondary stringer because of the curve in the transom.

At the bottom of the page is a plan view of the secondary and main stringers showing the lamination schedule.  As you will see in a following post, the secondary stringer is made up of ¼” Coosa laminated together to get to ¾” thickness and the main stringer is made up of ½” Coosa to get to 1 ½” thickness.

This is the Coosa Board cut plan.  Per this plan you need two ¼” x 4x8 sheets and four ½” x 4x8 sheets.  All the long skinny pieces are for the stringers.  The stringer pieces on the ¼” board are for the secondary stringers and they are 6” wide x 8’ or 6’ or 4’.  The stringer pieces on the ½” boards are the main stringers and they are 8” wide x 8’ or 5’ or 2’-6”.

The rest is pretty obvious, the only funky thing is I made the floor piece up under the bow by laminating two ¼” pieces together, otherwise you would need to buy another sheet to finish up.  If you are careful in your layout and cutting there will be plenty of small scraps left to make up the extra pieces next to the exhaust hoses, the little shelf on either side of the engine and the various other odds and ends, like the two roughly 11” x 14” pieces on either side of the gas tank.  

Dotted lines on the one piece are the cut out for the removable panel behind the engine. I would wait to cut that out till the final fitting of the floor pieces after everything under the floor is installed.  Side note: since the Coosa board is only a 1/2" thick, I added a 1" tall x 1/2" thick piece of scrap to the Coosa board that makes up the non-stringer side of the exhaust hose space.  I put it on the outboard side, the side closer to the secondary stringer. So the top of that piece is now 1" wide to give more landing space for the removable panel.  You can see it in one of my other pictures.  

To create the template for the bow floor, I set a thin straight piece of wood from battery box to point of the bow at the elevation of the floor then marked the side to side dimensions every 6”. I transferred that to a piece of cardboard to get close and then test fit and scribed lines on the cardboard till it fit neatly under the bow.  Transferred that to the Coosa, after a bunch of test fits and some sanding I got a nice fit for the Bow floor.