Great idea to try to get a group discount but keep in mind we may be comparing apples and oranges. When you say you pay $X, what does it cover? What are the deductibles. More importantly, what are the exclusions? Is the company any good if you have a claim. Among the bunch of us, we may have quite a sampling of "insurance products." If we can find a way to compare the overall cost/benefits of these products, we can make an informed decision.
Another thought on options as we could compile a list of our names, boats, boat and gear $$$ and shop it around with the best ranked insurance companies. A little competitive bidding may find the best and most sustainable deal. The real test of an insurance company is what happens when you have a claim. When you're "on your own" you tend to get a big price hike or dropped altogether. In a larger group "our" agent would be tempered with the fact that we can take "our" much larger group business anywhere so there would be much less of a knee jerk reaction.
I am not an insurance agent but I've been in business on my own for 16+ years and I have learned to shop for and buy a lot of different types of insurance. Are there others out there who have experience on this? We could put together a "steering committee" to try and come up with a strategy to take this forward.
Food for thought. But a great thread and idea to pursue.