I’m looking for input on the hull thickness survey. We’ve done the general survey every 5 years for the last 15 or 20. This will be the first time we are required to do the hull thickness (Audio graph) test
Yeah, OK. I think you said once that you have a Steel Pontoon boat, right? I've not dealt with a sonic test personally but I've heard some stories first hand, I wish I had better news to share. I've spent a lot of time in Boat Yards in the last few years and I'm on the board of the Lake Powell Yacht Club in Page where we own our own boat yard. The members who've had issues recently tell me that it's an expensive test ($2,500) and it's a ping about every square foot. I've seen the chalk all over the hulls and pontoons. They make their report about thickness of the material and send it in, it's quite clinical, not subjective, just the results mam. (Sgt. Joe Friday if you're old enough)
The reports interpretation and requirement's of maximum variance can differ by carrier but it's not just about thickness it's about variance in thickness. For those I've talked to even a small variance in thickness regardless of the depth of the material overall is enough to fail your hull or pontoons. In other words it's a percentage of the thickness, doesn't matter if it's a quarter inch thick material or and 1/8 inch, it's a percentage of deviation thinnest to thickest.(weird)
The newest steel boats on the lake are now 30 years old and their hulls are decaying if not outside in then inside out. (Steel and water) Last year at Wahweap Marina two steel mono hulls sunk on my dock, P dock. Seems within the last two years or so carriers have been taking more and more hits especially on old steel boats so they are requiring thickness tests and it doesn't seem like they are easy to pass.
If I were you I'd shop around to see if I could find someone to insure your boat who is not demanding the sonic test, a carrier who would offer you coverage on just a good out of water survey and pressure test, they might still be out there. Some members are reporting no problems with finding insurance after shopping around. So, I'd get my out of water survey and pressure test and fix things as requested. Then I'd go shopping for a yes with survey and documentation in hand but I'd leave it dry dock until I bound coverage just incase I had to go sonic. You wont know until you try, Best of luck!