I also have an ASW 15 insured with Costello. Hull is insured for
$14,500 and trailer for $1500. My premium was around $600. I have
about 350 flights and 200 odd hours. I am an SSA member. I don't know
why your premium would be so much higher. I also had a claim several
years ago for about $2400. They were very easy to work with. This
resulted in an increase in premium for a few years and then it dropped
back down.

Mike