Wednesday, April 23, 2008

Building the Mast

(Posted by Scott B. Williams)

I'm back in Jupiter, Florida this week, hired by David to build the mast for his Tiki 30 project. Working in the Boatsmith shop is always an interesting experience, and even more so on this project, which I've been involved in from the beginning in setting up this blog. A lot of progress has been made since I spent four days here helping assemble the hulls back in February.

Since I've already built the mast for my Tiki 26, Element II, I'm familiar with the process and so far the construction of the new mast is going smoothly. David and most of the crew have been out of the shop this week, working on a teak deck for one sportfishing yacht and the interior for another as described in his Liberty 42 blog. Most of the work I've done so far has been with one helper, Francisco, and it has been considerably easier than building a mast alone as I did for my boat.

David buys most of his lumber as rough stock. Below are the Doug Fir planks we started with. These are 18 feet long by 6 inches wide and a full 8 quarters thick. The mast walls for the Tiki 30 are 25mm (1-inch) thick, so we had to first surface this material with the planer and then resaw it to the proper thickness.

This is easy when you have the kind of serious tools David's shop is equipped with. The table saw shown here made resawing easy and also made it easy to saw the triangular wooden fillets required in the mast interior.

After processing the wood, the next step was to set up a form for laminating the mast parts to insure that we would end up with a straight spar. I used a similar system for building my Tiki 26 mast. The key is to insure that the form is perfectly straight and dead level. This insures that the finished spar will be true after all the individual parts are laminated.

David already had plenty of the large bending knees shown below that make up the form. The Boatsmith crew uses these for laminating teak covering boards for yachts and for such projects as the massive teak pergola we built last summer for a Palm Beach mansion. I set up the form to accommodate a length of 32 feet, as we are extending the mast by a couple of feet to provide more clearance for a bimini. Shade is essential for a boat that will be sailed in the tropics, and many other Tiki 30 builders have raised the mast height for the same reason.

On the backside of the table with the mast form, we have enough space to cut and glue the scarf joints. Here the side walls are being stacked four high to cut the scarfs. All the scarf joints are cut to a 12:1 ratio, so they are 12" long for the mast walls and 18" long for the square stock the triangular fillets are cut out of.

Cutting scarf joints is really easy with David's 6-inch Makita power planer. Here I'm using the stacking method with the planks each set back 12 inches, cutting them down to a smooth ramp using the planer.

By the end of the day yesterday, we had the two side walls completed, clamped on the forms with the triangular fillets glued in place.

The next step on the two mast halves shown above is installing the masthead crane and the pivoting mast foot. Below is the crane, laminated from solid teak, one layer in the middle 16mm thick and two outside layers 12mm thick oriented with opposing grain.

The mast foot and the matching step for the mast beam were also laminated today. These too are teak.

During periods of epoxy drying time when nothing else can be done on the mast, I'm also working on various other parts for the Tiki 30 while I'm in the shop this week. Today we laminated the rudders to the finished thickness of 40mm from two pieces of 9mm ply and two pieces of 6mm ply each. The laminations cured by late afternoon, and as shown below, I clamped them to a work table with the leading edges facing up so I can fit the hardwood inserts at the lashing points, as I described in my blog about building my Tiki 26, Element.

No comments: