Marine Plywood or hardwood for stringers?

[GSX455]

My old boat needed everything, so here is the view of the floor well, after I removed the old stringers How close to the floor should you get the stringer wells? Does the side wall fiber glass from the old stringer need to be cut down to the floor? See photo. I do not have the greatest tools, but have a 4" cutter grinder, what's the best tools to get close to the hull?
Also, What was left of the center stringer was 2x4 pine, marine plywood is always the best option, right?. If you could use wood, what hardwood is best?
I bought 4 yards of biax 1708 for 15 foot boat , what else should I get? CSM, which works with epoxy? I'm using progressive epoxy. I saw the many diy's articles but pictures on the old threads have low resolution, and I'm new to boats and pictures really help.

 

[Scott Danforth]

I used exterior grade plywood

yes, you need to remove all the old tabbing and grind alot more than you think.

skip epoxy, use poly. answer are in the stickies.

I hope you meant 24 yards.... 4 yards is no where near enough

 

[Chris51280]

read the stickies. If you go with epoxy, there are plenty of people here that used it. kcassells .
1708 and csm is used with polyester resin.

 

[kcassells]

Note; To put the comment in context;;
I used 1708 w/epoxy cause I am a newb for my first roll. It can be used but costs more in the end run.1700 is better with eeepooxxy and won't use as much glue/resin and easier to work with.
Still a newb!

 

[GSX455]

I'm glad to hear I can use epoxy because I bought a lot of it. I use polyurethanes at work, and some of these polys have osmotic blistering issues, epoxy sticks better too.

What remains of my center stringer is in the photo, as a template. The small piece to the right is the side stringer. I will shape this new one out of 3/4" marine plywood.

What do folks mean when they say to tab a stringer? When I make the stringer, I plan to seal of the wood with some epoxy, and then use poly with 12" wide 1708 and lay a over to tie it in to the hull. Is this tabbing?

Does tabbing prevent the rot from reaching the transom?
The transom had dry holes, and a small cutout showed very superficial wetness, hammer taps had a knock not a wet thud.
I hope I do not have to uncap this boat,; I do not have the space to do this.
Thanks for all the advice