I just signed my boaters insurance from Progressive. Brand new 2021 AR250. Quote covers full $65,000 value of boat and trailer in the event of total loss. Includes extras like wreckage recovery, fuel spills, any water based assistance/tow within 75 nautical miles of shore, roadside assistance on trailer (mechanical or tires - no charge), travel expenses with trailer failure >100 miles from home, collision, comprehensive, uninsured boater medical coverage, 'named storm' coverage(Hurricane) with higher deductible ($2,250), etc. This is for $1000 deductible. Policy is $708 per year(59mo). Comes with a disappearing deductible.
As stated by Julian, in FL we boat pretty much all year long, that coupled with FL being the boat theft capital of the world(lol), times the number of boaters means rates aren't as low as other states where boating season isn't yearly.