main mast step placement

[JeffM]

CS Builders,

I made a template to spec for the main mast step, dropped in into place where it fits well, measured back from the prow 22" to the location of the mast, dropped a plumbline and -- oops! The base of the mast lands right at the pointy end of the step. How big a problem is this? I could locate the step as is, but wonder whether the forces on the step would be better distributed over a larger step area (i.e. farther back, nearer the center of the triangle). When I try to position the step so the base of the mast is centered, it doesn't fit properly, and also runs into the foremost pair of bottom stringers. (On the plans, the step appears foreward of the stringers, whereas it fits better between the first and second pair.)

I could make the step wider and notch it to fit over the stringers. That would mean forgetting the step specs, and going for more correct placement.

Ideas?

[Designer]

Jeff,

You need to keep the mast in the designated position. Because the mast step fits in the curved forefoot, you can move the mast step fore and aft along the stem area like an arc. The object is to have a flat base for the mast to land on. The mast rakes aft 3 degrees and it is ideal to slope the top of the mast step 3 degrees aft so the mast will meet the step at 90 degrees. I usually put in the stringers after the mast step but it is not important, you can notch the step around the stringers if they are in the way. The mast is free standing so there is very little compression load on the step but there is lots of fore and aft and side loading.

Position the mast step so that the tube is about 2" forward of the aft end of the step* when the tube is raking 3 degrees and the top measures the right distance back from the stem. If the step doesn't fit the stem when in that position then you must adjust the step to make it fit. It is one area in the boat that it doesn't hurt to overbuild, in other words put in plenty of glass when you are tabbing it in. Also, I like to put about 3 layers of glass across the top of step for the mast to land on before I glass in the tube, because you never know when the mast will be dropped in and you don't want to expose wood fibers in an area that will be hard to get at later on.

*This gives you lots of area to glass to when putting in the tube.

[JeffM]

Thanks, Graham! That's exactly what I needed to know, and exactly why!

-Jeff

[Rob Blackburn]

I got a small disc of stainless steel about 2mm thick cut that fits inside the mast tube. It is about 78mm in diam to allow it to drop down and then the mast base sits on that. Same for the mizzen. That way no grinding on the glass at all.

Rob

ps Graham, boat is leaving for Fraser again on Friday. This time father daughter and girlfriend (hers that is) trip.... We are going with Mary Bryant again that has just had a rig change from sloop to twin masted junk.... More news later.

[Designer]

That sounds great Rob, look forward to hearing about your new adventure.