I was a member
of the ABYC Tech Board for six years, but some of my information may be dated or inaccurate. I remember that when standard H-40 was updated, there was lots of concern about what the end use of cleats (and other line securing devices) might be. Would mooring
cleats be used for horizontal loads, or would they be used for lifting? What direction would the pull come from (important when the mounting surface is long and slender, for example). Would bow eyes be used for trailering, or mooring
? What if someone were to put a 3/4" line on a cleat intended for 3/8" line?
If your boat is built to ABYC standards, I would have great confidence that the cleats are fine for mooring purposes, which would make towing a tube a walk in the park.
You can find an old version of H-40 here