An answer to bridge clearance
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I see
If you look closely, they have the bags tied to lines and tensioned slightly (they arent hanging straight down). My guess is that the bags are heavy enough without beign restained, any heel maks them fall "downhill" and causes the boat to heel over until they lay in the water and then tighten them up, or perhaps only until they reach the extent of the lines. To stand back up, you just reel them in! It's in in weither or not the bags have enough weight to overpower the heel even at a small angle of heel (the systme is stable - the bags have more heeling moment than the boat at any angle of hel. If they were only stable when far out, it would be a pretty dangerous rig and I dont think you could keep it there with line - you'd need a whisker pole or something.
If you look closely, they have the bags tied to lines and tensioned slightly (they arent hanging straight down). My guess is that the bags are heavy enough without beign restained, any heel maks them fall "downhill" and causes the boat to heel over until they lay in the water and then tighten them up, or perhaps only until they reach the extent of the lines. To stand back up, you just reel them in! It's in in weither or not the bags have enough weight to overpower the heel even at a small angle of heel (the systme is stable - the bags have more heeling moment than the boat at any angle of hel. If they were only stable when far out, it would be a pretty dangerous rig and I dont think you could keep it there with line - you'd need a whisker pole or something.
Mike,
54.5' from the waterline plus the antenna and wind instruments. We are headed that way next summer (to NYC). I might try it if the tide is real low. I'd still have to be aware of powerboat wakes while going underneath. I can see it now, my masthead sticking up through the roadbed because a powerboat went by and jammed me up there. Tom s/v Orion's Child
54.5' from the waterline plus the antenna and wind instruments. We are headed that way next summer (to NYC). I might try it if the tide is real low. I'd still have to be aware of powerboat wakes while going underneath. I can see it now, my masthead sticking up through the roadbed because a powerboat went by and jammed me up there. Tom s/v Orion's Child
That's iffy
Tom, at that height your right it's iffy. We've made the run for the last 3 years and will probably do it again in 08. Our 361 needs 50' plus antenna so the canal is not a problem. I'm surprised that you need 55' with your Hunter 33. I do agree with the power boat comment. We've had guys come through the railroad bridge on plane while we were waiting in line. Needless to say it made things ugly. They're not very courteous in the canal. Also met a guy at Utchs in an Island Packet that cleaned off the mast head light under the first bridge in. He waited 2 hrs for the tide to run out before trying the second one. Mike
Tom, at that height your right it's iffy. We've made the run for the last 3 years and will probably do it again in 08. Our 361 needs 50' plus antenna so the canal is not a problem. I'm surprised that you need 55' with your Hunter 33. I do agree with the power boat comment. We've had guys come through the railroad bridge on plane while we were waiting in line. Needless to say it made things ugly. They're not very courteous in the canal. Also met a guy at Utchs in an Island Packet that cleaned off the mast head light under the first bridge in. He waited 2 hrs for the tide to run out before trying the second one. Mike
Mike, a correction...
I have not personally measured it but the specs for an H33.5 provided by this site have it at 53'5" above the waterline, not 54.5' as previously stated. That's still pretty close when you add in the wind instruments and the VHF antenna but enough of a difference that I'm re-thinking the whole thing. I just gained a 13" advantage on the problem so maybe with a low tide, full tanks and the wife & kid swung out on the boom for a bit of heel, I'll be OK. What do you think?? Tom s/v Orion's Child
I have not personally measured it but the specs for an H33.5 provided by this site have it at 53'5" above the waterline, not 54.5' as previously stated. That's still pretty close when you add in the wind instruments and the VHF antenna but enough of a difference that I'm re-thinking the whole thing. I just gained a 13" advantage on the problem so maybe with a low tide, full tanks and the wife & kid swung out on the boom for a bit of heel, I'll be OK. What do you think?? Tom s/v Orion's Child
The stress is actually limited
The actual stress on the spar is limited by the boats righting moment curve. If they use water in the bags, then when the bags go into the water, the force is limited to the force or moment that normally would heel the boat due to wind action on the sails. I would guess that most boats can be heeled by force at the top of the mast without damage to the rig, unless maybe a fractional rig and a tapered mast. My above opinions are eyeball engineering, maybe (maybe not?) a NA would have a different perspective? The approach looked pretty creative to me. Since this guy has not bent anything, it looks like he is on to something. OC
The actual stress on the spar is limited by the boats righting moment curve. If they use water in the bags, then when the bags go into the water, the force is limited to the force or moment that normally would heel the boat due to wind action on the sails. I would guess that most boats can be heeled by force at the top of the mast without damage to the rig, unless maybe a fractional rig and a tapered mast. My above opinions are eyeball engineering, maybe (maybe not?) a NA would have a different perspective? The approach looked pretty creative to me. Since this guy has not bent anything, it looks like he is on to something. OC
In the days of wooden ships and iron men
it was common practice to careen a ship to work on the bottom . Ashley has a good discription of this proceedure. I simple terms it involved an eight part tackle rigged to the mast head and to a hard point on shore. Power was applied to the hulling part of the tackle and the ship was laid on her beam ends. In this case the greatest load on the mast is when the boat is on an even keel. As soon as she heels over the strain is shifted to the shrouds and some of the strain comes off the mast. At some point the load is equally shared by mast in compression and the shrouds in tension.
it was common practice to careen a ship to work on the bottom . Ashley has a good discription of this proceedure. I simple terms it involved an eight part tackle rigged to the mast head and to a hard point on shore. Power was applied to the hulling part of the tackle and the ship was laid on her beam ends. In this case the greatest load on the mast is when the boat is on an even keel. As soon as she heels over the strain is shifted to the shrouds and some of the strain comes off the mast. At some point the load is equally shared by mast in compression and the shrouds in tension.
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