Attaching the mast step

Wharram seems to like interesting mast steps, and the Hitia 17 is no different. The mast as feet that lock it to the beam fore and aft and "locating chocks" that locate the base of the mast laterally. The front block also prevents the mast from rotating and the middle portion gives a curved initial contact point for the foot of the mast to hook onto as the mast is rotated up into place.

So here is the plan for the front block, I have made it a bit wider than the sketch which I think looks better and will give more epoxy surface area to prevent shearing along the glue joint.

Now the mast step doubling block and the block are epoxied on. The sequence here was fillets, doubling block then mast foot block.

The block liked to slide around particularly with the clamps on the angled faces. It took some adjusting but eventually it sat centered and flush with the top surface.

Now that the epoxy has cured it's time to make sure the proportions and shapes look right.

Overall I'd say the mast step is looking pretty good and I seem to be getting the hang of the fillets. The second round worked out much neater than the first though you can see that i need to go back and clean up some of the excess.

We're still struggling to find a free day with good weather to do the hulls, but they are poised and waiting should the opportunity arise.

Mast gluing and details

There are a couple of small details that need to be taken care of so we can get to gluing. The mast foot is already shaped so that end is done but the top end of the mast needs some attention.

Here are the two masthead sheaves nearing completion. The grooves were shaped with a rat tail file and a little patience. all told these took about 20 minutes.

A test fit with 1/4" line which is size of the future main and jib halyards (halyard = rope that pulls up a sail).

The plans call for a space between the sheaves but didn't specify what so here is our answer: a 1/8" thick piece of douglas fir ripped on the table saw from some beam scraps. The two sides of are coated in epoxy since they will be hard to reach.

The whole unit is then glued together and ready to drop into corresponding cutouts in the mast halves.

We don't need these quite yet, but right to left shows the process or making the thumb cleats which will hold the stays at the top of the mast. The grain is oriented parallel to the outside edge for maximum strength even though the stays will be pulling toward the mast and downward. Who knows one day someone, probably me,f may try raising the mast by pulling on one and I'd like them to not break.

Which all lead up to the big event of gluing and clamping the mast halves together. I have quadrupled my army of bar clamps but still don't have as many as I would have liked for this job.

All told it came out nicely though and it's good to have the spars roughed out and ready for finishing when the rest of the boat is farther along. We're still waiting for the day when we have something that looks like a boat, hopefully that day will be here soon.

8-Siding the Mast and adding fillets

The mast halves have cured and were run through the table saw with the blade at 45 degrees to get down to eight sides. The mast foot fits into recesses cut into two halves and here is the rough fit.

The next step is to support the inside corners of what is essentially a rounded box section with epoxy fillets mixed with 50/50 colloidal silica and micro balloons. There will be a lot of fillets when we get to the hulls (soon!) so this is good practice.

Filler blocks are used to make the mast solid at the ends where the foot and sheaves are supported. The plans call for 1/2" ply but we had 1 1/2" x 1/2" fir scraps so we're using those instead which should be stronger and lighter. To reduce stress points from the sudden change in stiffness at the filler pieces we used the excess epoxy mix to taper the transition.

When we're happy with all the fillets we leave the mast halves to cure.

The recesses for the foot are done, the recess for the masthead sheaves will be next and then we can glue the mast halves together and put it aside until later for the final finishing.

Gluing the mast halves

Yesterday I rounded the edges on the sprit with a router which means the gluing table is clear so now we can work on the mast. The plans call for a box section with epoxy fillets which is then rounded using the normal progression of 4-sided to 8-sided to 16-sided to round. 

The first step is to make the two 'U' shaped halves, insert the mast foot and halyard sheaves and then glue the two halves together. Wharram suggests using screws to temporarily clamp the square pieces onto the larger flat pieces then remove and fill with thickened epoxy. Here is our plan to avoid screw holes showing in the final piece, though we ended up angling the screw to provide more depth.

The last thing we want is for the fir to split so each screw location s pre-drilled with a countersink bit. Here is the bit set for the right depth and the angle we decided to use.

To get the spacing right we used 1 1/2" wide cutoffs as spacer blocks. the square pieces are 1" square so that makes a 3 1/2" diameter mast.

Once both halves were aligned and screwed we could back out the screws, coat epoxy and then re-assemble.  It was a long day but getting the spars done will be a huge landmark on the way to sailing this spring.

Assembling the mast foot

Wharram uses a foot on the bottom of the mast and cleats on the cross beam to easily locate and establishes the rake of the mast. The mast foot also holds the cleats for the jib and main halyards as well as the mains'l downhaul.

The Hitia 17 uses two layers of 1/2" plywood for the foot, here the is the outline for one half drawn out on the plywood. You can see that the top of the cross beam is doubled where the mast steps and that a rounded block is added to the aft face which allows you to hook and then rotate the mast into place.

Here it is cut out including shaping the opening where the down-haul line runs down through the foot and back up to gain more purchase when tensioning the luff of the sail.

Next the two halves are epoxied together and clamped while keeping all the edges aligned.

Extra epoxy and wood flour mix is spread around the down-haul hole to make sure that the plywood is protected from any abrasion.

Once it dries it will be ready to glue between the two mast halves during final mast assembly.

Making the mains'l sprit

While buying the wood for the beams we went ahead and got enough for the mast and sprit as well. All the spars will be made out clear vertical grain Douglas Fir. These are the best sticks I could find in the stack at Hingham Lumber and man are they pretty.

The 2x6s will become the beam tops and bottoms, the 2x4s will become the mast and sprit.

Before going any further, I should point out what "mains'l" and "sprit" mean for non-nautical speakers. "Mains'l" is short for "main sail" which and the "sprit" which we are building now is the pole that holds up the peak of the main sail and is marked in green below. It is curved to allow the sail to have some shape when the wind is blowing towards the side the sprit is on.

I took advantage of the modular workbenches to re-arrange the basement for spar making. Right after this picture I rolled out a sheet of plastic over the work surface to get ready for lots of gluing and all of a sudden the workshop looked like a scene out of Dexter.

The two halves of the sprit were each coated with raw epoxy and allowed to tack up. I then realized that I hadn't turned one board end-over-end to reverse the grain orientation. So one board went very carefully back out of the basement through the bulkhead, spun around in the back yard and put back on the workbench.

The ends are propped up with boards and the middle held down with a paint can to get the right amount of curve based on the plans. The spring back for a two layer laminate should reduce the height of the curve by 1/4 to 1/3 so that has been factored in. The tape method of clamping is adapted from Michael Storer of Goat Island Skiff fame where you clamp then wrap  in tape to hold. The tape will support quite a bit of pressure, certainly enough to get a good amount of squeeze out.

Next I put on clamps over the taped sections, not to hold the two boards together, but to align the edges and keep them from sliding. Here you can see how the grain has now been reversed to prevent warping.

The next steps when the epoxy dries will be to round over the corners with a router, trim to final length, attach the thumb cleats and start varnishing.