It can be fixed, but the cost will be more than the value of the boat even if you do it your self. The problem is that a crack like that is usually due to a rotted transom.
And if the transom is rotted you can count on all the wood being rotted, floors and stringers.
You will have to pull the top off of the boat to get to all of this.. that crack need to be fixed right or it will crack again, and the whole back of the boat could come off while your going down the lake or river.There is no easy way to fix, no temp patch you can do.. cost wise if the transom isn't rotted ( highly unlikely ) would be less than $500 in materials.. your looking at maybe 2 gallons of fiberglass resin $50 , aprox 2 yards of 1708 biaxal mat $40, 3 yards of 1.5 oz $20 fiberglass chop mat. Gel Coat to match the hull color $20-50 dollars
You will need a electric grinder and about 10 (40 grit) flap wheels, a palm orbital sander and a variety of auto Velcro or stick on sand paper ( 80- 220 ) for the final sanding before the gel coat goes on.
If the Transom and other wood is rotted, your looking at aprox 900 - 1500 in materials and supplies needed to accomplish this job for all new wood, and all the fiberglass, resin and other supplies needed
If you have never done fiberglass work, and Im not talking about a fiberglass patch on a rusty car.. you need to research this a lot before you attempt to do it.
I have a PDF book on doing the transom, it will help you greatly, and I see your in AL if you are in North East AL and you want some advice from a guy who does this every day .. and you dont mind meeting towing the boat over to Chattanooga, TN
Id be happy to look at it and give you a expert opinion on what all needs to be done.
Or When I go down to Guntersville Lake to fish and your in no hurry I could meet you at Crow Creek .. where I usually launch from.. but I wont prob be back down there till mid Feb to fish.
Or I can just email you all the info I have on redoing a bass boat.. its up to you either way the advice and info is free.
Good luck with it either way
I fish There for I am
I love the smell of two strokes, and polyester resin just not at the same time 
AKA NRG , Fish, Fishalishious
