If 'the toerail is not holding the boat together' it's because it's 'sealed' with butyl tape. If you used 5200, it would in fact be holding the boat together.
In
Best Boats to Build or Buy, Ferenc Mate applauded our three-dimensional fiberglass flange on the C44s. He noted that, in theory, the three faces of flange (horizontal) and bulwark and hull topsides (both sort of vertical) are all held in compound curves and laminated together so that none of them can become distorted without complete disintegration, which would take vastly many times the load rating of any other structural element on the boat. In empirical fact, I know of exactly
ONE Cherubini 44 on which the flange was ever significantly damaged, and that involved a much larger vessel (barge or something) dragging into the C44 during a hurricane and then holding the C44 against a very handy concrete bulkhead to (attempt to) crush the C44 between itself and the bulkhead. The rigging pulled out and the rig came down, but the boat remained floating and underwent restoration at the shop. This is also the only C44 I have ever seen that sustained any puncture or fatigue of the actual hull; and for related reasons.
The three-faced aluminum toerail on production sailboats approximates the function of the fiberglass flange and bulwark. Properly bonded to the hull flange, topsides and deck (and not just sealed to keep water out), this becomes a
phenomenally strong structural member that permits
incredible holding power for anything fastened through it (like my shroud U-bolts and stanchion bases), prevents hull and deck distortion, prevents leaks, and resists damage due to collisions, groundings, and rather rude close encounters with even
stunningly severe and stubborn concrete quays. (Note the words I use: '
phenomenal', '
incredible', '
stunning'. These are known as
understatements.) Short of lifting the boat 30 feet in the air and dropping it squarely onto its beam ends, I will (perhaps arrogantly) submit that if you've sustained any bending of the toerail or crushing of your topsides at the level of the deck, your toerail is probably only (tenatively) sealed with butyl tape or (worse!) silicone and not structurally bonded to the fiberglass with polyurethane, as it should be by design. I can't answer for what Hunter did after about 1978; but one reason I bought the particular HIN I did was because after 37 years (at the time) that thing was still structurallly bonded with 5200 and
NOT LEAKING (and that still hasn't changed).
Short answer to the question:
- If you use butyl tape, torque specs are meaningless. You can 'tighten' it as hard as you like and the butyl will just keep squeezing flatter till it's microscopically thin. The bolts will never be truly 'tight'; and in this case lock washers, thread locker and locknuts are a must lest they rattle loose(r).
- If you use polysulphide, prepare for it to not bond to the metal well. Polysulphide was meant for wooden boats. It does not work well with nonporous surfaces.
- If you use a hybrid (Life Seal), this is pretty good. Tighten to 'first grunt' using a ratchet of about 6" and let it alone after that.
- If you use a polyurethane, ditto; but it will provide more strength than Life Seal will; otherwise they are similar in this application.
- If you use silicone, SHAME ON YOU. See the butyl tape answer; but add in the complete inability, when you discover how terrible silicone is in this application, to be able to ever replace it with anything else due to the slimy residue it will have left in this extremely vital structual bond. And it loves mold. And it breaks down in seawater. And... but I have posted on this before -
https://forums.sailboatowners.com/index.php?threads/silicone-removal.189943/#post-1435386