Your Boston Whaler hull has many deep scratches, probably caused in loading the boat on the trailer improperly. You should repair the trailer so it will no longer damage the hull during loading or travel on the highway. If you don't fix whatever has been gouging those deep scratches before you begin to repair the scratches, the hull will soon be deeply scratched anew.
The hull also appears to be discolored from immersion in water and appears to have no barrier coat. You need to thoroughly clean the hull before beginning repairs to the laminate and gel coat. If you begin sanding dirty gel coat you just infuse dirt into the repair area.
I would not trust repairs made with a pre-mixed putty and catalyzed resin to be sufficiently well-adhered and waterproof for work below the water line as will be needed in this case.
You may find my lengthy and detailed narrative of repairs with epoxy and gel coat resins to be informative. See
THE EPOXY CURE
http://continuouswave.com/maintenance-logs/epoxy/If you plan to leave the boat in the water for more than a few days at a time, read the owner's manual for advice on how to protect the hull. See
http://continuouswave.com/whaler/refere ... nance.htmlIt is very likely that as soon as you begin to grind out the damage that needs to be repaired, the repair area will grow in size and become too large to be effectively repaired with just a small amount of a pre-mixed putty compound. Thick application of a putty without laminates and thinner resins will make a weak and brittle repair.
I also recommend you read this article:
REPAIRING HULL DAMAGE THE WHALER WAY
http://continuouswave.com/whaler/refere ... epair.htmlFor advice on hul repairs from Boston Whaler, read this article
http://continuouswave.com/whaler/refere ... tions.htmlYou will note that in none of these articles are repairs made with a pre-mixed putty catalyzed with a small amount of additive to create curing.