I have a Dagger Cortez 16.5 and my bulkheads are just now beginning to leak. How should i fox them?
Lexel
If it is a poly boat then Lexel may work well. It is what we’ve always used on leaky bulkheadfs in poly boats.
If composite then 3M 5300 (or 5200?) adhesive.
…lexel
clear Lexel is what’s used from the factory. It’ll work fine
Fox them? You mean fix 
Repair
The English major was too busy correcting your spelling he forgot to tell you to capitazize the I.
Use Lexel only. Do not waste time or money an silicone. It will adhere temporarily.
I tried silicone that’s why I’m warning you.
Lexel can be purchased at a paint store (it is use in residential and commercial construction) or from a outfitter / canoe-kayak dealer.
The paint store usually sells it in tubes that hold twice as much and are 1/2 the price but you’ll need a caulking gun.
Clean and dry the bulkhead well. Use a hair dryer. I tried to partially repair mine and it didn’t work so I ended up taking all of the caulking/Lexel out of one side and resealed it.
The next day I did the same to the other side.
Once you put the bead of Lexel in the crack use your finger to spread it. Have a rag handy or a roll of paper towels. You need to use a damp finger on the Lexel.
A little liquid dish detergent in a cup will do well.
Start the bead at the top of the bulkhead. You’ll have to work quickly and don’t let you damp finger hit the kayak or the Lexel won’t stick.
A rubber glove
Works well for smoothing the lexel. Around here lexel is pretty easy to find in smaller, squeezable tubes. Using a gun can be difficult in the smaller areas of the hatches.