I have the same issue on my old 1236.
Finally getting around to it today. I have discussed 3 options in my mind.
I will be putting some 2x2" aluminum tubing crosswise on the bottom with
self sealing pop rivets through the bottom.
I want this stress crack SEALED prior to installing the floor.
okay - correction - it is not really a "stress crack" . . . it is worn out from
dragging the boat on a rough surface such as concrete.
So you must replace that worn off aluminum with something solid.
If you do not plan to drag your boat on concrete, then you don't have to be
as aggressive with the repair, such as welding.
I have a lot of work do do on this boat so I will address this issue first, then
post the step-by-step procedure of how I repaired it.
option 1: wire brush and clean it really good, form a piece of aluminum sheetmetal to mate
to the inside of the strake. Apply epoxy, press in the patch, fiberglass cloth over that.
option 2: Same as above, marine flexible adhesive, metal patch, let it cure, then more adhesive.
maybe a layer of fiberglass cloth imbedded in the adhesive.
option 3: apply a patch to the outside of the strake with flexible adhesive and a piece of aluminum
sheetmetal to form a patch.
do NOT use BONDO !!! it is NOT flexible. Works great on cars but not worth a hoot on a tin boat.
if you can not find a piece of aluminum sheet, use a beverage can . . . sand off ALL the paint down to
bare metal. Maybe use a couple or 3 layers on the inside of the strake and one on the outside.
do not sand the metal down to 600 grit to get a glass smooth surface. Use 40 grit to leave a rough
surface so your epoxy and adhesive to have a "tooth" to grab on to.
If you think you need some thicker metal for your patch, very quietly sneak your wife's aluminum sports
drink bottle and cut it up with your 4" cut-off wheel or hack saw. Do it quickly and hide the remnants.
Or, you can do the more honorable thing and go to your local Salvation Army or Goodwill store and buy
some for about half a buck each. (good to have a few on hand anyway)
Keep in mind - - you are not patching a race boat or a tank, you are only patching a small tin boat.
Don't try to "over think" the situation. Stay inside your comfort zone of your skill sets.
Also, keep in your mind, if your repair fails, the worse that will happen is you will have a SLOW LEAK !!!
LOL you will not get swamped and sink immediately.
Be back later with some pics of what I did.