Is is safe to go aloft while on stands?

[Nodak7]

No amount of explaining can convince some people why something shouldnt be done, and they will risk life and limb trying to prove people wrong. If they get away with it enough times they may even be able to convince others to follow them. I would compare doing this to Russian roulette. You'll get away without a scratch, until you don't.

If you get the keel to slip or knock a jack loose, there will be no escape. Its not like its going to slowly roll over in slow motion and youll be able to simply let yourself down without harm. Its going to fall over like a giant domino and you'll probably be dead, or worse. If your real lucky it could have a domino effect with the boats along side, and you could knock a whole row over.

Anchor, do you know what the story is behind this picture? Where? When?

 

[Don12364]

Thank you Weinie - at least you understand.
Clanker:- As former Tech Director of medium sized company, now Chairman, I feel I do understand Newtonian Physics. See diagram below. Total ADDITIONAL force on each stand, assuming 2 in use, one fore & another aft = 44lb. i.e. 22 lb per support.
Dynamic effects aside, how would the climber get his C of G more than 2' away from the mast? Even standing on the end of a spreader only exerts the same force as standing on the gunwhale.
For interest in a strong gale and my boat on its mooring, my masthead sometimes goes outside of my max beam.


Davidsailor - Thanks for your contribution but moving one's head only makes same effect as moving it whilst standing on deck.
BTW Newton doesn't mind where one takes moments from.

 

[Nodak7]

Thank you Weinie - at least you understand.
Clanker:- As former Tech Director of medium sized company, now Chairman, I feel I do understand Newtonian Physics. See diagram below. Total ADDITIONAL force on each stand, assuming 2 in use, one fore & another aft = 44lb. i.e. 22 lb per support.
Dynamic effects aside, how would the climber get his C of G more than 2' away from the mast? Even standing on the end of a spreader only exerts the same force as standing on the gunwhale.
For interest in a strong gale and my boat on its mooring, my masthead sometimes goes outside of my max beam.


Davidsailor - Thanks for your contribution but moving one's head only makes same effect as moving it whilst standing on deck.
BTW Newton doesn't mind where one takes moments from.

Donalex, there is one thing that I was considering while reading this. If they are that delicate then it would be dangerous to put a cover over the boat since the windage may exert as much or more pressure than a person aloft. Your thoughts?

 

[Sumner]

Thank you Weinie - at least you understand.
Clanker:- As former Tech Director of medium sized company, now Chairman, I feel I do understand Newtonian Physics. See diagram below. Total ADDITIONAL force on each stand, assuming 2 in use, one fore & another aft = 44lb. i.e. 22 lb per support.
Dynamic effects aside, how would the climber get his C of G more than 2' away from the mast? Even standing on the end of a spreader only exerts the same force as standing on the gunwhale.
For interest in a strong gale and my boat on its mooring, my masthead sometimes goes outside of my max beam.


Davidsailor - Thanks for your contribution but moving one's head only makes same effect as moving it whilst standing on deck.
BTW Newton doesn't mind where one takes moments from.

I agree with you guys and would go aloft if the yard allowed it. I can see where they wouldn't even if the boat was set in concrete due to the liability thing and they just don't want someone falling for any reason in their yard.

One thing to consider on all of this is the size of the boat and who placed the stands.

Our boat is 20,000 lbs. and the yard placed the stands and they have done that for dozens of years. We lived on the boat for 3+ months this past year up on stands when working on her and were on her when Debbie went by, but the winds were only in the 50+ mph range. The boat vibrates some in higher winds, but that is it. It is rock solid. I'd feel safer going up where she is than in the water moving around. If I fell either way I'd hit the deck so the water doesn't offer an advantage.

With the Mac I wouldn't go up on the water or on land, but her mast comes down in a couple minutes so no problem.

I do need to go aloft when we go back to put a LED anchor light on. I'll take it from this that the yard probably won't allow it and I can see their point so will do it in the water if they don't allow it. If they do I'll go up.

I've spent tons of time on high ladders and roofs and construction so heights don't bother me and I'm careful how I move and what I do in those situations. Someone who doesn't feel comfortable in those situations for sure shouldn't put themselves at the top of some mast regardless of if the boat is on land or water,

Sum

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[David W]

I dont believe it is. I believe its a 3rd class lever making the fulcrum the keel, the top is the force (man at the top), and the jack stand is the load. That keel is not coming off the ground, and its not likely to skid until the hull contacts the ground, if at all. I believe the jack would simply push away allowing the boat to fall over.

Of interest is that even using your lower calculations, the man can easily produce lateral loads at the top of the mast that exceed the loads generated by a 100 mph wind.

In any case I just cant see how on earth its worth the risk. My life is worth more than any boat, and certainly more than whatever is on top of it. That jack slips and the boats going over, and the man at the top, 60 feet up, is going to have a very short period of time to contemplate his death.

Im not interested in the math, but I wonder what kind of velocity the man would reach at the top of the mast as the boat went over. Or, if the mans on a rope at the mast head, and the boat rolls over and slams into the next boat, will he twirl around the mast a bunch times like a tether ball before the mast breaks loose?

Ok, the last paragraph cracked me up...