Light reading.https://classicaquasport.com/smf/index.php?topic=8901.0
You can look for a thread in the FB forum by Capt. Matt. He had his sitting near the ground. Hopefully he didn't use photobucket. If he did and you are using the photobucket patch and the right browser (like Mozilla) then you can still see them.The support doesn't have to support every inch - mostly to keep the shape like the hull sides and the centerline and chines of the hull. As suggested, if you don't over support the hull bottom maybe the hook will "sag out" and then when you lay some layers of 1708 over the bare hull, it'll lock it into place.
Every flatback ive seen has that hook in the keel, i wouldnt mess with it (unless its in the actual hull bottom). But it doesnt look like the actual hull is hooked much, just the keel strip. Even the nice n straight solid hulls ive seen have had that keel strip curve in em. Although a small hook in the actual hull bottom would probably be a benefit on these hulls to get the bow down.But do extend the keel just about to the transom aft, tapering back to flat where it ends. Will help it track better...Use some straight pieces of lumber along/under the keel and chines to keep the hull shape, and pull some strings like mentioned. I actually like the look of that mako console in there, just needs a frameless windshield about 1/4 the height
As far as the liner, I guess it adds another step in closing in the transom, as I have to remove it to be able to tab the transom into the inside of the hull.
I put mine under the deck. I cut the center stringer on the backside of the center compartment back to the stepdown in the top of the stringer. Put a bulkhead at that point. I made my own tank ended up being just over 40 gal. Once I remove the section I glassed the whole area to tie the hull and stringers together. Hope this make sense. I see your in Boynton I grew up in lantana now I live in the Acerage area. If you have any question let me know.
Basic ideas.https://classicaquasport.com/smf/index.php?topic=9842.msg102175#msg102175https://classicaquasport.com/smf/index.php?topic=14384.0https://classicaquasport.com/smf/index.php?topic=10789.msg105572#msg105572Many of the Flatback re-builders removed the stringer system and built new. This allows for designing space for a below deck tank. If however you are keeping what you have, you have to first decide where the tank will be located and then remove the center stringer to allow for it. Build a bulkhead and create a "coffin' for the tank then re-attach the center stringer to the new bulkhead. If you keep the "windows', you'll need more room aft.First, you must decide on tank size. Visit the Moeller site to get ideas on tank size and dimensions.http://moellermarine.com/product-category/fuel-containment/permanent-fuel-tanks/Good luck. Mod Edit: I see FL. beat me to it.