Great sailing weather for me today. Unfortunately, I got as far as the boat launch when I realized I didn't have my mast pin for my Nacra 450. So I came home :-( Can't find it anywhere and don't know what size it is, but I found a long shank padlock that fits not quite snuggly. Don't think I'll try that.

Anyway, I thought the mast hinge pin was a safety feature that prevented the mast from coming off the ball. But after doing a search on this site, I've seen mention of leaving it off when sailing. So what's its purpose? I don't want to head out if it's supposed to be on.

Next question is what size is it?

Thanks :-)

It's a pin you use only when raising or lowering the mast. You remove it once the mast is up. The mast shall be free to rotate on the ball, so it can help form a nice aerodynamical shape to your mainsail. Hence the need for rotation control..

Your mast will not hop off the ball, unless something unusual happen. Just tighten the rigging before you go out, and you'll be OK. (you will be OK even if you forget to tighten your rig).

The compression generated by mainsheet, sails and sidestays are tremendous, and they all end up in the mastfoot, so dont worry about the mast jumping off the foot. If your are in need, a screwdriver does the job while raising the mast..

That makes sense, Rolf, thanks :-)

I also found that it's a 1/4 x 2" shaft. And I found a 1/4" x 2.5" bolt. Even has a hole drilled in the shank, but looks like it's not needed now.

Had I not lost it originally, wouldn't have learned this. One way to learn, I guess.

I also have that question: what is the purpose of mast pins?

They make sense on boats which have a hole drilled directly through the ball mount (some Hobies) - in that case, the pin allows the mast to be raised in a straight line without veering to the left or right. Then it can be removed when we want to the mast to rotate (i.e. when sailing). When the mast is small or light enough to put that kind of weight on a pin, this makes a lot of sense.

But on my Nacra, the pin only seems to hold the mast to the ball bearing, without controlling direction. Unfortunately this doesn't do any good whatsoever. One time we dropped the mast while raising it; the force was so great that it removed the mast from the ball and shattered the pin! (amazingly, the mast and the ball were both unharmed).

The lesson seems to be that you're "on your own" when it comes to raising the mast, and nothing is a substitute for manpower and a good winch.

The mast pin is crucial when steping the mast! It is VERY HARD to keap the mast base on the ball without it! I know a lot of sailors that use philips head screw drivers when stepping or unstepping the mast, and then just take them out. Nice and simple!

I worked out a couple of short lines with a loop on one end that hooks over the crew trap handle and a clip on the other that clips onto the barberhauler attachment loops that are clamped under the main beam clamps. Even if you don't have a barberhauler, you could add the loops for this purpose. The trap lines then keep the mast from swaying side to side from lowered to raised position. Don't make them too tight. You'll need several inches of slop to get them clipped on with the mast rotated and they need some slack to get the clip unclipped. Even with a little slop, the mast will only sway side to side a few inches. Works great for lowering in a cross breeze.

None of the mast step pins are designed to keep the mast in column while raising. The Hobie pins and plates are nice in that the mast can be pointed straight forward instead of rotated 90 degrees but are not strong enough to keep the mast from going side to side either. I had a 5.2 that didn't originally have a captive system for keeping the mast base on the ball during stepping and it was a PITA.

The reason that we remove the pin while sailing is a safety thing. Imagine that a shroud or forestay were to fail and the mast came down. If the pin was in the mast base, you've just built a 26' nut cracker - and you're the nut. If the mast base is free the rig comes down rather gently and slowly (not that I've experienced this personally, but I've seen it happen) without damaging anything.

My mistake - the hobie pins do NOT keep the mast in column.
I was confusing it with the pictures I saw in the Phepps cat sailing book on assembling a Dart.

Thanks for the "nutcracker" analogy. I'd just assumed that the mast pin would break in a situation like that.