Friday, April 15, 2016

Launch Notice and Final Build Update - April, 2015



Pícara Sails!



Pícara, my Hazardous Zero-9 Merlin Rocket build and a Keith Callaghan design, was successfully launched and sailed this morning on Lake Travis, near Austin, Texas, USA. She gracefully sailed in light winds and quickly responded to mild gusts.



More photos, videos and a big blog update (after a year in hiatus) will come in the days ahead!


Pícara and I on launch day.

Pícara after her first sail.

Splash!

A little bit of bubbly...



2015 - The Missing Files (Coming Soon!)

Varnishing The Decks

I selected EPIFANES Clear Gloss Varnish for being a traditional marine varnish, based on tung oil, phenolic-modified alkyd resins and having maximum U.V. absorbers. Being in Texas and going sometimes through significant temperature variations within a single day, not to mention the hot Texas Summer, I wanted a product that not only had the ability to handle our weather but also had superior flow, gloss and durability.

Preparation, per Epifanes, included sanding the deck and rails, and cleaning the clear epoxy thoroughly with alcohol and Epifanes Thinner.








Thinning ratio varies depending on the the number of coats applied. No sanding is needed if re-coated within 72 hrs.




I used a  good quality, clean, natural bristle brush and applied 4 coats of Epifanes varnish.

The product is very easy to apply and results are of great quality if instructions are followed.



I'm very pleased with the high gloss finish she now displays.

Pícara is now ready to handle the Texas weather. 



Rigging Pícara

Perhaps the most expensive aspect of boat building, and for a good reasons: Safety & Performance . It can't be said enough, choosing the right rigging hardware is key for accomplishing both. Buying parts as the build progresses can save money and help offset the big cash outlay at the end. Many of the suppliers have discounts throughout the year and I took advantage whenever possible.

Hardware

For Pícara, I followed the recommended hardware listed in Keith Callaghan's drawings. In some cases where the exact part was not available in the US or in the UK, I consulted with Keith to select a comparable or better replacement. Hardware wood screw holes or machine screw holes were filled with epoxy and 404 High-Density filler, which is a thickening additive developed for maximum physical properties in hardware bonding where high-cyclic loads are anticipated

My main suppliers in the US are Annapolis Performance Sailing (online) and West Marine (local).


The Jib Cleat Brackets were fitted each with a Harken 150 Cam Cleat and a Harken 092 Cheek Block.

The cam cleats and the cheek blocks were bolted through the brackets.  


Bow tank deck covers fitted with stainless steel screws and recommended silicon sealant.

Ronstan 5/8" jib track x 18" fitted with corresponding track ends. 


Allen Webbing Bridges (2" Grey) were fitted on the plan landings to secure the buoyancy bags. 

Harken's swivel base with H150 Cam-Matic

Starboard side Harken H306 & H302 wire through deck blocks and covers for the shrouds and lowers.



Port side Harken H306 & H302 wire through deck blocks and covers for the shrouds and lowers.

The Tiller & Rudder Stock

These parts for the Merlin Rocket are relatively easy to source in the UK. In the US, however, this is not the case. After an extensive search  and contemplating the costs of buying one from the UK and shipping it over to the US, I decided to build my own until I can source one (new or used) for a reasonable price.

Having some extra marine plywood, mahogany and epoxy available from the build, made my decision a bit easier. The design requirements were simple; a breakaway system of relatively light weight but strong enough to house the rudder blade.

For the specific measurements and characteristics, I used advanced composite models as reference. Here, I start by laying out the rudder case assembly shape and fitting the 27mm mahogany spacers to house the 25mm rudder blade. Above the case is a pocket for the tiller carbon tube.

Once the spacers where fitted, I applied three coats of epoxy resin to the entire rudder case.
I proceed to select the pivot point and trace the breakaway turn radius.


After cutting the breakaway radius, I simulated the movement of the rudder inside the case and found out I had to make slight modifications to allow the free movement of the rudder blade.

Almost there... I had to cut the aft spacer of the rudder case at an angle where the trailing edge of the rudder blade swings inside the case during breakaway.

I drilled a 10mm hole at the pivot point on the rudder blade. Since the pivot point was at the trailing edge of the foil, I cut a 27mm carbon fiber spacer from a 10mm carbon fiber tube. Later, I inserted the carbon fiber spacer with epoxy and colloidal silica to make a strong rudder blade screw hole. I also applied three coats of epoxy resin to the exposed radius on the rudder blade.
Closeup view of the spacer and screw hole.


Here's a view of the rudder case with a slot on top for the carbon tiller tube and screw holes to secure it. The pintle and gudgeon screwed onto the case at the right location after fitting their equivalents on the transom. I also cut 10mm carbon tube inserts for the pivot screw holes.

An aft view of the rudder box showing the single block for the control line to keep the rudder down under way.

Final fitting test to ensure free movement on both directions before tightening the screws. 
Clearance test over the transom in all directions for the tiller's 1m x 30mm O.D. / 26mm I.D. carbon tube.


Installation of the Ronstan Battlestick carbon tiller extension and camcleat for the rudder control line. 
 The final article less the rudder blade.


Next... The Hoop

Thank you for watching! More to come soon...


Sunday, March 8, 2015

January, 2015

Finishing the Spinnaker Chute

In retrospect, I should have provisioned for a more holistic approach to finish the spinnaker chute and make sure I designed a 1 piece cap to fit nicely over the rough opening, covering the breasthook, the stem and the gunwhales. I envision this piece now of solid Mahogany stock with pre-finished rounded edges so that only minor touch ups are needed afterwards.

Well, hind sight is 20-20. My reality called for adding small pieces of solid Mahogany stock to round off the corners and line the sides of the opening. 


Adding the pieces to round the corners. I also clamped an L-shaped jig over the deck from the gunwhales to provide a surface to clamp the corner pieces from. Also placed a wood block at the stem to prevent the clamps from damaging the deck.

Fitting the side pieces.

Next, I bevel the deck at the bow to make room for the nose cap.

Epoxy Coating The Deck & Strakes


Prior to varnishing the deck and rubbing strakes, I apply 3 coats of West System 105 epoxy with 207 Special Clear Hardener. This will be the base for the layers of Epifanes clear varnish I'll apply once the average daily temperature warms up within the manufacturers recommended range.

View of the foredeck.

View of the side decks.

Aft view from the bow.


View of the foredeck and the carlins from the transom.

View of the spinnaker chute opening.

Full view from the bow.


Carlin detail on the aft port side as it turns around to the transom.


Carlin detail on the aft starboard side as it turns around to the transom.

Carlin detail on the port side as it turns around from the side deck to the foredeck.

Carlin detail on the starboard side as it turns around from the side deck to the foredeck.


Foredeck after applying 3 layers of epoxy with West Marine 207 Special Clear hardener.

Thank you for visiting!

Wednesday, December 31, 2014

December, 2014

The Carlins (Continued)



After testing the fit of the starboard deck carlin, I taped the deck edge and setup a dry run with the clamps to see where the clamps needed to go to ensure a tight joint.








Prior to fitting the carlins, I scarphed both carlins' ends to 13 cm off the ends to round off nicely around the front and aft curves and be ready to receive the next pieces.

To protect the gunwhales I used a pipe insulation foam tube that comes with a slit on one side.

View of the transom from the bow. I marked the location of the different clamps along the carlin.

I used a cedar timber as counterweight on the port side as the starboard side clamps were heavy enough to tip the boat a bit over the cradle.

Depending on the angle of the carlin, I used a smaller clamp to secure the bar clamp and prevent it from slipping

Same counterweight technique used on the starboard side when clamping the port side deck carlin. 


Then, the all important dry run to set up the clamps at the right place to obtain a tight joint between the carlins and the top edge of the deck





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The dry run setup view from the front.

Placing the clamps near where I'll use them during fitting.


View of the port side from the stern after fixing with epoxy resin and colloidal silica.


View of the port side from the bow after fixing with epoxy resin and colloidal silica.



View of the port side carlin after removing the clamps. I used the hand plane as the first step to remove the excess material.


The hand plane does an excellent job at removing the excess material and the blue tape at protecting the top of the deck.

View of the port side carlin after removing the clamps.

The inboard edge of the forward deck is covered with a 60 mm wide x 2 mm thin Mahogany veneer I cut with my table saw. The veneer goes around from the inner edge of the king plank to the end of the scarph on the starboard side carlin. The veneer bent nicely around the curves without problems and were held in place with clamps during the dry run show on this image.

Because of the torque applied during the three-dimensional bend, small gaps appeared between edge of the deck and the veneer.

To ensure a tight joint between the deck and the veneer, I used the same counter torque and clamping technique used when fitting the rubbing strakes.

I carefully clamped a cedar timber over the deck where the timber was not actually touching the deck. I used scrap pieces of wood in between to prevent imprinting on the deck. Later, I used bar clamps to pull the upper edge of the veneer tightly against the edge of the deck. 

View of the counter torque and clamping technique used on the forward starboard side.

 View of the counter torque and clamping technique used on the forward port side.


When building the deck frame it really pays to plan where to place the reinforcements blocks to also serve as clamping blocks perpendicular as much as possible to the tightest curves.

Another view from behind.

And a final view from the port side, completing a 360° view of this clamping technique.


I have collected a small amount of Mahogany dust from my belt sander to mix with epoxy and apply it to any of the deck joints. This ensures almost invisible joints once varnished.

For the transom veneer I used two separate pieces since I didn't have a plank wide enough (about ~16 cm) to trace the transom curvature and cut it out in one piece.

View of the transom after adding the protective blue tape and ready to fit the transom veneers.
View of the transom from the starboard mid section after applying epoxy resin and colloidal silica to fit the transom veneers in place and securing the pieces with a few clamps.


View of the transom from above after applying epoxy resin and colloidal silica to fit the transom veneers in place and securing the pieces with a few clamps.

The ends towards the port and starboard carlins were scarphed to meet the corner pieces.

For the aft corners around the transom, I followed a similar technique (if not the same) as used by Laurie Smith on Rob Holroyd's MR 3708 Wicked.
Designer Keith Callaghan was kind to share the reference photographs and explain the technique.
A veneer is fitted to the port side rounded corner with epoxy and colloidal silica.

A veneer is fitted to the port side rounded corner with epoxy and colloidal silica.

View of the concurrent fitting of the venner over the aft corners.


View of Pícara from the bow after fitting all the carlins and inside veneers.


View of Pícara from the bow after fitting all the carlins and inside veneers.

Next, as with the rubbing strakes, I followed the same process to remove the excess material until the top of the carlin is flush with the top of the deck.

1) Shaving, 2) Sanding with an electric palm sander, 3) Hand sanding.

Here's an image of Pícara after sanding down the top edge of the carlins and inside veneers.



Next, I traced the bottom line of the carlins from the top edge of the carlins and veneers based on the dimensions recommended by Keith Callaghan and the ones I chose around the curves to give Pícara the stylish look she deserves.

For tracing the bottom lines at the forward and aft curves, I used a piece of scrap 3 mm plywood I had previously cut across the grain. It proved very flexible and did the job without a problem. 

Rough finish view of the aft starboard rounded corner after shaving off the extra material.

Rough finish view of the aft port rounded corner after shaving off the extra material.


Rough finish view of both aft rounded corners after shaving off the extra material.



I went around the inside shaving and rough sanding of the bottom edge of the carlins. Rough finish view of the inboard edges of the forward deck after removing the excess material on the bottom edge.






View of both aft rounded corners after rounding off and smooth sanding the top and bottom carlin edges.



View of the inboard edges of the forward deck after rounding off the edges and smooth sanding the veneers.


Carlins accomplished!

I then fitted a rough block of Mahogany to cap off the end of the king plank.


Later, after sanding the king plank's end cap down to about 13mm of thickness, I fitted a 15cm x 4cm x 12mm piece of Mahogany stock to be the wedge under the mast step.



View of the Mahogany stock wedge for the mast step.
Selden mast step over the wedge.



Thank you for visiting my blog! Until next month.



Cheers and happy sailing in 2015!