If your boat trailer has much age, which most Stratos do now, you should check the trailer suspension. Especially if you have much squeaking.
I was replacing a stuck caliper and found all the shackle bolt bushings and the equalizer completely worn out.
I should have checked it a long time ago being it is 16 years old with a lot of towing miles on some rough roads, but out of site, out of mind. Just turned up the radio so I couldn’t hear the squeaking.
I replaced the equalizers, bushings, shackles and bolts/nuts. Springs and mounts were still ok. Had around $100 in parts/shipping and it’s extremely quiet again now.