For the last six seasons, have been running a 1969 32' Seagoing, made in Florence Alabama, on the Missouri River. Micro-attended to the outside of the hull when I bought it in 2001, with a two-part epoxy on top of sound steel. Discovered that after 39 years, had "issues" on the inside.

Have de-floored, and removed all scale and loose rust and paint. Now I know you guys are going to tell me I have to re-hull if it is bad enough, but bear with me.

Four years ago I rebuilt the Volvo AQ 130, and treated the engine compartment which had very similar rust with this new-generation polymer, Rust Bullet. Not even a bloom after 4 years, and that's how I am treating the inside of the hull. Whacking it all with a hammer still gives a good tone. My question is how can I determine what is left as far as thickness? The boat obviously sat on a trailer for many years, and the rust is heavier to starboard.

I figure this may give me a few more years. I have been patching the dings that the Missouri River will give any boat, on the outside, with this stuff for 4 years, with great results. What do you think?