Spruce Box mast

[Akacake]

Just wondering how a "spruce box mast" is rated as a mast? How does this design hold up; does the fact that it''s a box and not solid have any advantages; is spruce better/worse over other types of wood; wood over aluminum??

Thanks in advance,
Akacake

[Jeff_H]

Generally Sitka Spruce is considered the best wood for building masts because of its high strength per pound. Hollow spars generally are lighter for a given stength and so are preferable to solid spars in most cases. Box Spars are the easiest hollow wooden spars to build and result in a pretty good strength to weight for a wooden spar. They give up quite a bit from an aerodynamic stand point.

In small boats, (under 20 feet)wooden spars can be quite comparable in weight to the normal run of the mill aluminum spar but as rigs get larger woden spars quickly become substantially heavier, less strong and more flexible than aluminum.

The down side of wooden saprs is that the glues have limited lifespans, and they can look perfect on the exterior and rout out from the inside. Their greater weight reduces stability and increases roll angles.

Jeff

[MArch]

The boat that we just bought has a spruce box mast on it, so I just went through the research you are doing. Generally, I found that spruce masts were well regarded strength-wise. They do weigh a bit more than aluminum, but one source indicated that the extra weight aloft actually made the roll of the boat more comfortable. On some older, short-masted gaff-riggers they used to haul anchors aloft during storms to reduce the roll...

Anyway, the thing that I would really be concerned about is the rot. We thought that our mast was in pretty good shape--the owner had just had the boat partially re-rigged 3 years ago and had kept up the mast painting since then. Well, during survey we discovered that the mast had such significant rot at the gooseneck that the rigger would not even go aloft to examine the rest of it. The rigger told me that my experience was typical--he finds rot in almost every wood mast he examines.

If you are looking to buy this boat, I would get an experienced rigger to go aloft and check the whole spar. Examine every pentration and pay particular attention to the masthead. In our case, we found that we needed a whole new mast--and the next one will be aluminum!