Pulpit height?

[Gerald]

I am getting ready to bend the pipe for the pulpit and cut the guard rail posts. At what height should I place the cables?
The sailboat is 39' and I will be traveling down the coast and around to Chile.
Gerald

[Alan D. Hyde]

I'd say at least waist-high, lest they turn into trip hazards, but many here are likely to disagree...

Alan

[ 08-26-2005, 01:39 PM: Message edited by: Alan D. Hyde ]

[htom]

I suspect that the ideal height is just below armpit height, but I doubt that you'll do that.

[Dan McCosh]

The minimum height for offshore racing is 24 ins. This sounds low, and won't provide anything to lean against. The idea is mainly to catch a sliding body before it goes over the side. Double lines are required as well. In practice, the lower lines will end up stronger, although the key point here is a very strong anchor point at the ends, not the stanchions themselves. They are merely a backup to the primary jacklines and harnesses. Rigged taut, they can provide a steadying handhold. Minimum 1/4 ins. wire with the appropriate end anchors (about 5,000 lbs.) is good.

[ 08-26-2005, 01:50 PM: Message edited by: Dan McCosh ]

[paladin]

as a minimum have the top wire at least in the small of your back....and double the stanchions if you are going offshore....
Between Iceland and the Faeroe Islands a wave cought the keel of my 38 footer and did a snap roll...I was near the mast and my lifeline was attached..My body floated in the air while the deck moved putting my back against the top wire...the stanchions on either side went to about 45 degrees before the lifeline stretched tight and stopped me.....and my stanchions were tube inside of tubes.....

[Gerald]

For something that might save my life I would want them high. However, since this is a sailboat the genoa is also something that needs to be considered. I recently junked out a rotten 36' sailboat and it used 1" stanchions that were 24" high. The stantions look flimsy and out of place on my boat. I have purchased 1 1/4" 1/8" wall stainless. I cut hardwood dowel pins today to place inside the tube. Paladin .... I guess that sailing to Antarctica would be considered off shore? When you say double the stanchions .... I was planning on around a 30" high stantion and you are suggesting a 42" high stantion. My 200 pounds would probably bend 1 1/4" at the height you are suggesting but would do little at 24". My plan was to epoxy in the wood pins. Sound reasonable or weak?
Gerald

[Dan McCosh]

The tubing in stanchions isn't the main point that carries the load of a lifeline. If you look at the boat plan from above, you see the curve of the lifeline forms a kind of caternary. The load of someone pushing outboard on this curve at midpoint is translated to a tension load at each end of the line which is asignificant multiple--roughly 5-10x. If the line is tensioned, the stanchions act more or less like spreaders, more in compression than bending. The anchor points take the primary load. Too many lifelines are interrupted with weak clips, usually to make them removeable, the ends are not anchored to a very strong point, or they are left slightly loose. A heavy person can easily hit with an impact of 500-1,000 lbs., which would bend over virtually any simple pipe. With the line tensioned to very stong end-mounting points, the impact can be restrained and contained. The problem with lengthening the stanchions, while it makes the line higher, is that it also ends up establishing angles at the ends that are weaker. A truly strong, high, (over 30 ins. or so) system ought to include substantial bulwarks, not rely on tall pipes. The other problem with tall stanchions is that they leave such a large space underneath, the scenario where you slip and fall easily allows you to slide underneath.

Our lifeline stanchions are 30 ins. stainless pipe, with 1/8 ins. wall thickness. The bases are cast stainless, through-bolted to a structural beam with four 1/4 ins. bolts. The end points are on 1/4 ins. welded plates, likewise through-bolted with four bolts. Lines are bare 1/4 ins. 1x19 wire. There are no breaks or gates. The setup is designed around about a 6,000 lb. tensile load. When the lines are set up solidly, they also offer a reasonable handhold in most conditions.

[ 08-27-2005, 08:34 AM: Message edited by: Dan McCosh ]

[Ian McColgin]

I was admiring the lifeline and rail system of Deva (now for sale by the way) at the WoodenBoat Show yesterday. The stauncheon bases are an open pattern cleat of his design where the uprights recieve the stanucheons. The normal sailing top is a rail of ss tubing made neatly into the regular stanucheons (one per cleat). The lower line passes through loops welded to the stauncheon - no weakening holes. For off shore he adds a higher stauncheon to the other hold in each cleat and wire for the upper line.

Many boats have the lifelines come down a bit in the way of the pulpit to give the jib room. Except for racing where every bit of "free" sail area has its minimal advantage, I do not hold much with decksweepers. They obscure visibility, can hold tons of water on a wave, and have very high stress sheeting due to the clew's geometry. Have the tack on a little pendant to get it up a foot and have the clew at least high enough that where the foot passes the mast, it's at the same level as the gooseneck.

Such a sail will nicely clear the lifelines.

If you're a bit oldfashioned and go with hanked on jib, that tack pendant give just the space you need to turn your downhaul into the long line you need to lash the jib (sweedish furl knot - really a chain knot that surrounds the sail) to the upper lifeline very neatly. I've done that on Grana happily alone in the dark in a strong gale (Force 9) and it's surprisingly safe and easy if your lifelines and pulpit are good. It's still well to have a tether that's about one armlength long.

If it's not on a bow sprit, a pulpit with two horizontal rails that carries a harmony of the bow's curve is wonderful and you can get in front of the sail squatting secure, butt well held in the lower narrower rail and enough room for the chest with armpits just over the upper rail. From here you can haul down the most recalcitrant jib if you're too cool to have a down haul or if you're messing with a jammed furler. Remember to take a deep breath when you feel the boat drop out from under you.

G'luck.

[Gerald]

Ian
Thank you for all that great information. Are you saying that lines are pulled tight with a force of 3 tons?
Gerald

[Ian McColgin]

It was Dan, but he means that the wire and anchors should have 6,000# capacity. They are not tensioned that tight.

You do want them tensioned reasonably tightly, which is usually about as much as you can get on the turnbuckle by hand.

The gates should have proper struts on the stauncheons and good pelican hooks with keepers. If you have it tight enough, the hooks take some hand force to secure.

I think a 30" high top line is nice but then you should have two lowers.

If the lifeline is properly tight, then when you crash against it the strain at the tops of the staunchions will be minimized and the stress will be mostly in the anchor points, hense the emphasis of these being really strong. Simply shackled to a little welded loop on the pulpit is not strong. Better to have a proper U band around the pulpit tubing.

[Dan McCosh]

No. That's the working strength of the wire and fittings on my boat. High as it seems, a 250-lb. body hitting the wire can generate that kind of pulling force on the wire. Otherwise, I keep the lifelines tightened with turnbuckles until they feel solid.

[Dan McCosh]

I'd add that I have a personal prejudice against fastening the lifelines directly to the pulpit. I've only seen a few pulpits with the appropriate bracing to handle the anticipated loads. I prefer mounting the lines independently, leading down to a deck-bolted plate, rather than attaching them to the pulpits. This after bending and tearing out a pulpit.

[Gerald]

Thank you Dan. I am wondering how in the heck you managed to tear out a pulpit, other than hitting it head on?
Gerald

[Dan McCosh]

It was the stern pulpit, which came loose when the lifelines took some of the shock of a bad jibe. The pulpit was supported by four vertical posts. If I used a similar system, I would add a diagonal brace.