Don't push on stanchions! Here's why...

[mkriley]

Originally Posted by Suijin

How have I turned a defect into a feature?

"The stanchion where I fell backwards was bent out at 45 degrees. If it had not bent, I might well not have been able to get my feet out and ultimately get myself back on the boat. Who knows."

[senormechanico]

If they even HAD stanchions, they were probably short and light to save weight.

I know they didn't...but if they did, they'd be a "feature".

[Island Time O25]

I believe stanchions which can't take a pull in or a push off sort of like a balcony railing which cannot take the weight of a grown person without that person falling down below. Kind of the defeats the whole purpose for which they are put there in the first place. And telling people not to use them as a lift up to the boat is like telling your house guests not to lean onto a porch railing thus admitting you have a faulty or weak railing to begin with. I don't see any difference. And just as with a house porch railing, perhaps after 30-40 years it is time to re-bed or replace as may be necessary.

And if you have a 20 ton 40 ft boat perhaps its stanchions should be that much more robust than a 5 ton 30 footer. But definitely they should not suffer or deform from being used as a hand hold for getting onto the boat.

[Scot McPherson]

Originally Posted by thinwater

Nice, actual math. Yes, the force will likely be more than 250 pounds.

a. An 8-knot stumble (13 ft/s) = 200 x 13^2/64 = 528 ft-pounds. Add a little down wards fall (2ft x 200) = 400 ft-pounds) and the 800 ft-pounds might even be a little light, demanding on the size of the boat. But clearly the correct order of magnitude.

b. The stretch will be a lot more than 3 inches, since the stanchions will bend. The force will not be steady, but gradually increasing in a difficult matter to predict. Let's assume the stanchions bend 6 inches and the actual absorption range is more like 9 inches. Assuming the The force increases linearly, the peak force will be about 2 x 800/(0.75)= 2133 pounds. Since the BS is 4500 pounds, we are past the WLL of the cable (900 pounds), but this is normal for foal protection equipment, and within the range generally accepted by military and climbing standards (generally around 1200 pounds for harness impacts).

So in a worse-case fall, rails will bend, but the sailor will be retained.

And for those who believe they are a hazard, no one said you need to stand tall when it gets wild--get low. You can't fall over a rail if you are crouched, kneeling, or crawling. This is obvious. Your first reflex when you loose your balance should always be to get low.


As for using the lines, I'm a big believer in pulling up. It will not loosen them and can give a lot of stability.

Agreed, the math can get complex when you add factors for the lines, stretch, slack and absorption of forces across several stanchions in progression and all that, but I was trying to keep it simple and demonstrative that the forces on stanchions is often a lot more than 250 lbs, and even more than 600lbs. Depending on the fall, it can exceed several thousand lbs of impact force.

[rhubstuff]

Just added to my crew briefing: "If you're on the weather rail and we take a knockdown, do NOT grab the lifelines. They're not designed to be pulled inboard like that. Just let yourself fall to the lee side lifelines. Maybe they'll hold you."

[hpeer]

On our big boat some of the stanchions developed cracks. They didn't appear to be stress cracks as they were in straight unbent tube. I found them when one tube bent very unexpectedly and I then examined the rest of the tubes. 30+ years old.

I made new ones to replace them and all other straight stanchions. The gates and pulpit looked OK. So the ones I replaces I raised 2 inches. I also inserted a piece of about 8" ss heavy wall tube several inches long into the bottom of the stanchion tube. That reinforces the bottom section of the tube making the lever arm shorter. Being a steel boat the stanchions fit over solid rod pins and are supported by a ring welded to the toe rail. I've used heavy dynamene as lifeline, it's thicker and easier to grab, and softer if you fall on it.

So far seems to have worked out well. One stanchion was bent by a yard mishap, and then rebent in a kerfuffel during a bit of a gale, main sheet hooked a long bolt on an attachment, now gone. I was able to straighten, with some determined effort. I may replace that one as I made a couple of spares.

We do lust after tubular railing. Once we win the lotto it goes on.

[Suijin]

Originally Posted by mkriley

"The stanchion where I fell backwards was bent out at 45 degrees. If it had not bent, I might well not have been able to get my feet out and ultimately get myself back on the boat. Who knows."

Not my boat. Was a race boat.