interesting mast step option

[benz]

Discovering after weeks of searching that no mill or distributor will sell me less than 1000 lbs of the tubing I want for a gaff mast in the length I need, I found a light pole company whose pole is exactly what I want (same thing, different Google search. If only I had known!) It comes welded firmly to a base designed to be bolted to a concrete footer. I was going to simply cut off said base, when it occurred to me that I could perhaps just stand the base on deck and bolt it to the partners, with a suitable compression post beneath. It seems unconventional, which makes me ask: does this raise all sorts of red flags among you riggers? I'd love to hear any pros and cons.
Thanks,
Ben

[Brian Duff]

there is no reason you cannot buy the lengths of pipe you need (of course only in 20' poles). we do it all the time. no need to buy 1000 lbs - that is just nuts.

More info is needed on the step design to determin if the one already on the flagpole can bear compression in additon to bending stress.

[benz]

Hi Brian,

There is certainly no shortage of twenty-foot lengths out there, but I want a forty-foot length. I'm leery of a butt weld or a sleeve joint, or anything that involves welding on tempered aluminum (yes, yes, the base is welded on, but since the specs call for T6 temper, it's re-tempered after welding). Anyway, the base plate casting is ASTM A356 aluminum alloy; no reason why it shouldn't take far more compression than would make the pole buckle. I'm concerned more with tweaking the deck at the partners if the windward shrouds should ever be slack for any reason, though I can't think of a scenario where they would be.....
Ben

[Brian Duff]

my concern is not that the base is not made of hard enough material, but rather that the pole butt compression is not transfered from the mast to the deck . If you look at many of those light pole bases, the only contact points are out at the four bolts and not through the middle ( this is to make it easy to adjust them to stand level, they are often fit onto threaded studs with nuts above and below. just be sure the step they sell can bear compression. As to the slight movement that might be realized as the boat moves in a seaway and the rig/hull flexes, just bolt the step down with hard rubber bushings between the step hole and bolt with a large heavy washer on the bolt head that ensures the bolts cant get throught the fastener hole, that would solve things. (think engine mount). A step on that boat only need be 4 -3/8" bolts, where the lamp pole probably has 3/4" fastener holes ( I haven't check what the lamp pole might have , just guessing)

There is no reason to be concerned about the hardness difference from welding the joints, especially if the correct sleeve is fit to reinforce the welded butt joint. I have seen many masts that are just butt welded joints without sleeves, and they didn't fail there ( we have one we repaired two years ago that bent/buckled about 6' down form a plain butt joint on welded 5" alum pipe (if I recall the size ) suprising that the butt joint didn't break, but it didn't.

of course there is the added advantage of a nice taper on those flag poles...

[benz]

Thanks, Brian

The rubber foot thing is a good idea. Your instinct was correct: the base has holes for 3/4 bolts. Since I designed the partners to have a pole go through them instead of on them, I'll probably still just chop off that base and keel-step the thing, but still, I like to fully explore all the options.
I've heard good testimonials on welded masts, but being the worrier that I am, I know I would spend every dark and stormy night just waiting for that weld to fail, and balefully eyeing the place on the mast where I knew it to be.
When you sleeve two poles, do you manage to find a separate piece of tubing with just the right OD to fit inside the two pieces being joined, or do you take a bit of the same tubing and slit it lengthwise to make it smaller around?
Ben

[Brian Duff]

Ben,
sometime just the right piece of tubing is available. Most times we buy a piece of the same size but double the wall thickness, and turn it down on the lathe to fit inside perfectly. We achieve a seriously tight fit this way, and then we 'rosebud' weld throughout the splice area and butt weld the seam.

keel stepping would be the way to go, imo

[benz]

Thanks, Brian. I've always wanted a lathe.....
I, too, think keel stepping is the way--it just seems like a waste of a really burly base. Maybe I should mount the pole upside down and bolt a bushel basket to the base for a crow's nest. I've always wanted a crow's nest.....
Ben