Sunday, November 30, 2014

November, 2014

The Rubbing Strakes (Continued)

Next I sanded and finished fairing the entire outer face of the rubbing strakes. Then, I trimmed the rubbing strakes to width per station based on Keith Callaghan's drawings. I would recommend leaving only 5 mm extra material on each end for margin of error.

Unfortunately I didn't do that and decided to cut the excess material after fitting the rubbing strake. I used my circular saw and used an aluminum ruler as a rip fence. It worked well.

Between Station 2 and 3, the rubbing strake begins to widen. I chose to begin the transition at 13 cm before Station 3. Then, at Station 4 it reaches its full 50 mm in width.

I marked the profile of the rubbing strake with a pencil and using my block plane I proceeded to shave off the excess material until the desired width was achieved.

Between Station 6  and 8, the rubbing strake's width changes from 50 mm down to the width of the gunwhale. I again decided to do a step down design from Station 7 to 8. Using Dad's old French curve ruler, I traced the curve I selected. Here's to you Dad!

Using a coping saw, I sawed along the curve...

...and then along the line for a few inches. Then I shaved and sanded the excess material left towards the rear.

After the rubbing strakes were cut to their width per station, I proceeded to round off the outer edges using a sanding block first followed by free hand sanding.

Port side rubbing strakes after rounding off the edges.
Starboard side rubbing strakes after rounding off the edges.

Aft view of starboard rubbing strakes.

Starboard side rubbing strake around mid-section.

Aft view of port side rubbing strake at transition point from from full width.

Port side rubbing strake at transition point to full width mid-section. 

I still have to fit the small rubbing strake section on the bow, right in front of the spinnaker chute. But I'll wait until I can fit a larger piece so I don't waste epoxy resin mix.  

The Carlins

The carlins on my boat are made of 60 mm x 9 mm solid Mahogany wood stock. I purchased a 17' x 8" x 3/4" board and cut an 8' piece for the port and starboard carlins.

But first I had to make the pattern. For this purpose I purchased an inexpensive 8' x 4' x 1/8" sheet of Lauan plywood at the local home center and cut a 12" wide plank.

It was very easy to bend it over the carlin's pine stringers around the side decks and later trace a pencil to outline the shape of the carlin.

Later I used my scroll saw to cut out the template. I added 5 mm on both sides of the lines for margin of error. This is the template I cut out for my port and starboard carlins.

Next, I clamped the template over the stringers to test its fit and realized I had to cut out 3 small notches for clearance where the space frames and the jib sheet cleat meet the carlins' pine stringers.

Then, I placed the template over the Mahogany plank and traced the pattern with a pencil.

Using my scroll saw, I cut along the traced lines on the Mahogany plank.

Here is the carlin stock at 3/4" thick.

Using my table saw, I cut the carlin stock in two identical halves. One for port and one for starboard. 

Next, I clamped the starboard side carlin in place to test its fit.

Here is an image of the process during the dry run. To get a tight joint against the deck line, I had to use bar clamps against the rubbing strakes. To protect the wood work, I used an 8' x 2" section of pipe insulating foam around the rubbing strakes.

View of the starboard side from the transom.

I'll use small clamps to hold down the carlin against the lower pine stringer.

Thank you for visiting.

Happy Holidays and Happy New Year!

Friday, October 31, 2014

October, 2014

The Rubbing Strakes (Continued)

 After removing the clamps and cleats I had to step back and spend some time thinking about what I had to do next. This is delicate finishing work. I can't afford to make a mistake since that would probably mean replacing a rubbing strake piece.

I had to develop a technique that would take me down several steps to achieve a smooth flush surface between the deck and the rubbing strake. I decided to do it in 3 steps, each subsequent step slower than the previous one.
  1. Shaving with my Stanley block plane
  2. Coarse sanding (80 grit paper)
  3. Fine Sanding (220 grit paper)

The blue tape served as protection during the entire process and prevented me from getting too close to the deck. Shaving took me close to ~0.5mm off the deck. From there, coarse sanding took me down to the blue tape until it started to peel off. Then, light sanding to a smooth finish between the deck and the rubbing strake.

Getting to the joint was like uncovering a treasure in the sand. Anxious to get there but cautious not to damage it.

I'm pretty happy with the joints I achieved for being this the very first time I do this type of wood work.

Always sanding along the deck grain too avoid scuff marks.

View of the port side as I sand down the rubbing strake.

The scarf joints came out better than I expected.

View of the port side rubbing strake after the initial 3 step process.

View of the aft port scarf joint between the aft rubbing strake piece and the next piece.

Photograph of port side rubbing strake piece #4 while sanding the excess material off the front, before fairing.

Next, the aft section of the same piece before sanding and fairing.

View of port side rubbing strake piece #4 after sanding and initial fairing.

Working down the aft scarf joint with the belt sander.

Same scarf joint after sanding and initial fairing.

View of the aft starboard scarf joint after sanding and initial fairing.

View of the forward starboard scarf joints after sanding and initial fairing.

Here she is today.

Next steps are to sand and finish fairing the entire outer face of the rubbing strakes. Then, trimming the rubbing strakes to width per station based on Keith Callaghan's drawings.

Until the next update... Fair winds and fun sailing!

Tuesday, September 30, 2014

September, 2014

The Rubbing Strakes (Continued)

Last month I fitted the forward and aft rubbing strake pieces on both starboard and port sides. Then, I scarfed the inner ends in preparation for the mid-section piece. I projected a tangent line off the gunwale to the rubbing strake and proceeded to shave and sand until a smooth flat scarf joint surface was achieved.

Next, I placed an 8 ft long x 120mm x 9mm rubbing strake piece against the starboard side gunwale. The curvature of the required rubbing strake piece becomes evident here. I placed the aft end of the rubbing strake piece against the end of the scarf of the aft piece and held it in place with a bar clamp over the side deck. Then, I bent the board around the gunwale and clamped the forward end the same way.

I left about 5mm of excess material over the deck on both ends. Then, I traced a pencil line on the rubbing strake right over deck line and under the  gunwale.

Here I'm holding the rubbing strake piece against the side deck and the beginning of the forward piece scarf to test the fit.

Unfortunately, it will require 4 rubbing strake pieces to do each side since the rubbing strake has to be at least 50mm wide from the edge of the deck.

Had I measured that requirement sooner I would've cut longer aft pieces or cut a board about 180mm wide by 9' long for the mid-section.

Once the lines are traced, I moved the piece over a temporary workbench to measure the width of the piece I'll cut and make sure it is at least 60mm in width (50mm + 5mm extra on top + 5mm extra on the bottom).

Using my band saw I cut along about 5mm off the pencil lines. Noticeable is the banana shape of the mid-section rubbing strake.

Dry run to test the fit prior to applying an epoxy resin with colloidal silica mix. Again, I use 1" scrap strips of 4mm marine plywood to protect the deck from the bar clamps. 

Front view of the clamping setup.

View of the clamping setup from underneath. Making sure the rubbing strakes are tightly held flat against the gunwale is critical to ensuring a tight joint with the top of the deck and the bottom of the gunwale.

Before fitting the rubbing strake permanently to the gunwale, I apply blue tape along the edge of the deck for protection.

Inside the boat, my cedar timber counter weight to offset the weight of the clamps while I'm working.

All clamps on deck!

Over the inner edge of the side deck, I place the scrap strips of plywood for protection.

And here is the view from down under from the rear.

This time the view is from the front.

Next, I followed the same method on the port side.

Another view of the port side from the front. The second time it goes a lot faster.

And the port side view from down under.

For the last piece on the starboard side I used again the 4" x 4" cedar timber over the forward deck to clamp the bar clamps from for the counter torque technique and hold the rubbing strake piece tightly against the top edge of the deck.

View from the front...

View from down under... I used small clamps to ensure the scarf joint was held tightly during gluing.

Same process was followed on the port side.

Thank you for visiting my blog! Happy sailing!