Rudders
Making our Valencian Rudders
When we purchased Paikea, she had an LPintact Port Rudder and a temporary Starboard Rudder. While this situation worked fine, it was not ideal if chasing any sort of performance from the vessel. When we hauled out the boat in Valencia, we discovered that there was a set of America’s Cup yacht rudders in storage. They were the rudders from the Spanish America’s Cup challenger Ibidrola. We took splashes off the existing rudders to make new ones from foam and glass.While, these rudders are way too big for our catamaran, we were able to use these to make a mould for a matching set of rudder blades for Paikea.
As the cradle Paikea was on in the boat yard was quite low, we were unable to remove the entire rudder and stocks from the boat. Partly due to this limitation plus the limitations in our budget, we decided to reuse the existing stocks and build the blades to glue onto these. As you will already know, this shortcut ended up coming back to haunt us on our TransAtlantic crossing/
The first step was to remove the old blades from the existing stocks. The original rudder on the Port side was a hollow stainless steel tube, the Starboard side with the emergency rudder was made using solid stainless steel tube. The solid tube is a much stronger tube and a better solution than a hollow one. The rudders were full of water and were a mission to remove as we had no choice but to chip away the blades from the stock. https://youtu.be/7IndtywMSkM
The stocks then had to be cleaned and prepared for the new blades to be attached. To make the blades, we took a splash from the America’s Cup rudders to make a mold. The foam and glass blades were made in the mold and then fitted to the existing stocks. Our plan is to have winglets on our rudders to combat the hobby horsing effect that happens on catamarans of this size. As we were on time and budget constraints we decided to leave the winglet project for a later date. The solid inserts etc that we would need to attach the winglets to the rudders were built into the blades to allow us to upgrade the rudders at some point in the future.
See our videos on YouTube describing the process https://youtu.be/7IndtywMSkM
Materials
- Airex C70 80kg/m3
- Eglass 400g/m2 double bias
- Eglass 300g/m2 cloth
- Polyester resin
- Fillers Cabosil and Qcell
- Peel ply and laminating consumables
The process of prepping the rudder stocks and gluing on the blades is shown in this video here https://youtu.be/WhHi6bQtzzA
Losing our Rudder
Sailing with our new rudders has proven very enjoyable. They have improved the steering performance of the boat noticeably. Unfortunately, we lost our rudders while crossing the Atlantic Ocean a year later. The Starboard rudder stock was original and made from hollow stainless steel. Even though we had been very thorough in inspecting the stocks and there were no obvious cracks or corrosion, it would appear that the stainless steel tube was compromised. It failed and the rudder fell off 800nm west of St Lucia https://youtu.be/Nmbsd8tJ2gg
We are now looking at this project again. This time we will need to build new stocks and rudders in the Caribbean. Given the fact that materials are difficult to source in the islands, especially if you want to do the work yourself it is proving quite challenging. Also, the fact that it is not easy to ship things to the islands without an address is making our current project a challenging one! https://youtu.be/tdr2Zl2rKAQ
Carbon fibre stocks will be designed by us and we will get our buddies at C-Tech sailbattens in New Zealand to build the tubes for us and send them to us here in the Caribbean.
The Latest Thoughts for our new Rudder
After sailing over 4000nm and collecting a massive amount of data along the way, we now have a good idea on what shapes work better than others https://youtu.be/rH01rSAawbQ From an engineering standpoint it is fantastic to be able to produce and analyse our own data.
Rudders 2.0
Or that be 3.0? Whatever incarnation it’s time to begin the rudder-building process. This time in the tropical French West Indies. Now that we have a design we are happy with we can look at actually making them. We had the rudder stock made to Shayne’s specifications by our friends at Ctech in New Zealand. They were able to ship the 2 carbon stocks to us here in Antigua and while we were waiting for them to arrive we could start looking at how we were going to shape the rudder blades.
The first step once we have the foam is to start cutting out the shape using templates we printed on board. Next, we then had to laminate the eglass to the shaped pieces of foam. We then had to glue the foam to the correct thickness then glue on templates and start hand shaping.
More sanding and building the blades once the laminate is cured.
We also needed to make sure the dimensions we sent to C-Tech are correct. So we had to pull the broken stock out of Paikea to measure the dimensions. It’s crazy how quickly the growth takes hold here in the tropics.
The pictures above show the bottom end of the rudder stock where the rudder snapped off. You can see what remains of the rudder stock below the rudder bearing.
Shaping the Rudder Blanks
Once the basic rudder outline has been cut out and the pieces of foam glued together to get the correct thickness, it is time to shape the rudder blank. Obviously we could have got this all done had we had access to a CNC machine but since we are sailing through the Windward Island chain without access to a workshop we have had to hand shape the rudders.
Shayne cut the foam and glued templates at each point where there was a change in thickness. Then he could sand each piece of foam to the correct shape.
Shaping the Rudder Blank
Shayne cut out templates at the sections were there was shape change so he could hand sand the pieces to the correct shape. Once he had the shape he wanted, we then had to hollow out the rudder blank to fit the new carbon stock. The foam was very fragile in places where it was thin. Doing this job without breaking the foam was challenging.
Next step is gluing the three pieces of the rudder together and gluing the stock into the foam.
The last few pictures show laminating a torque tab over stock to foam.
