Okay, so I think I have come up with some pretty good workaround.
I have been working with a machine shop and they basically cleaned up and rejuvenated my bolts and internal thread inserts (inside the mounts/brackets) - to work like new. The insert/internal threads are shorter (minus approx. 2 threads that were stripped/cross threaded in my tower) but the guys reassured me this is going to be better than redrilling/reinstalling. Please bear with me!
First off, this is NOT meant to be a SOLUTION, just a temporary fix. But I think it is pretty darned good, actually. The only drawback - this will NOT be ideally suited for those who need to put the tower up and down frequently. The mod will STILL WORK, but full implementation involves a special, final "tightening maneuver" that would be impractical for frequent use. (see below - at the end)
The idea is super simple - basically to lengthen the usable thread of the factory hand-wheel bolt - to increase the usable thread count from 6-7 turns per factory to approx 14+ (here). Moreover, a special implementation sequence ascertains those bolts are going nowhere! as far as potential pull out (no early withdrawals).
There are no new parts involved, just some modifications of the existing (two) bolts. If necessary, those hand-wheel bolts can be replaced for some $40 a piece (Screw, Knob F3F-U724D-00-00 $39.27) - so there is an easy way to go back to the original setup. Those are the only parts that get modded - the two bolts.
Here is the long and short - in one picture - factory on the left, modified on the right:
Here is couple more pics, different angles:
Here is the difference (qualitative view) in the reach on the inside
Unmodified (before):
And modified (after):
Here is how the bolts sit inside the tower - approx 3/8-1/2" deeper than the factory (after):
Before:
After the bolt modification, the spring and plastic washer NEED TO BE REMOVED. Also remove /do not reinstall the nylock nut. This is to permit a deeper reach of the bolt - a critical part of this mod/approach.
Here are two short video clips showing the movement range of the modified bolt with and without the spring/washer.
First one is of the bolt (modified) WITH the spring and plastic washer in place:
This does NOT work well - not enough threading depth.
And here is the exact same bolt W/O the spring and washer:
This is good - can be threaded in aprox 14+ turns.
And here is the most important part.
Hand wheel wrapped in a towel and tightened with a wrench - into the base/mount/bracket. However - BEFORE the modified hand-wheel bolt is put in place and tightened, the under-the-hull-cap bolts holding the bracket are loosened up. Those are 3/4 nuts, deep socket, can be reached with and extension bar or by removing the speaker in the coaming above the rear seats.
(don't worry, in most boats those will be a bit loose already... so just do not re-tighten UNTIL after tightening the hand wheel bolts)
Those bolts (under the hull cap) are tightened AFTER the hand wheel bolts are in place - this puts sideway pressure on the bolts making it essentially impossible for them to pull out!
And there you have it. Let me know what you think.
EDIT: I finished after dark so no more pics. I also do not want to post pics of the whole job for other reasons.
EDIT 2 (for clarification):
Within the existing mechanism, increasing the length of thread engagement seems to be the key to safety.
One can do this easily by (
adopting @McMark's new bolts idea or) grinding/filing the factory bolt plastic stem (as in above) AND removing the spring/washer/nut from the factory bolt to enable it to thread in deeper.One can get almost an inch of engagement with the modified factory bolt. That would pretty much guarantee some much greater level of safety without any additional mods.
The only inconvenience really is longer time for deployment (14+ turns vs 6-7) and the inconvenience of not having the spring to bounce it and the possibility of loosing the bolt (which would not be secured with the nut - internal, inside the leg).
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