Carbon Front Beam and Longeron
As you can see we have played a lot with Paikea and what we thought would be an improvement to the design. Much of it has been developed from an idea once we found that certain piece. In the case of the front beam and longeron, we wanted something that would allow us to use the longeron for sailing rather than storage. Finding cut sections of carbon mast allowed us to think creatively on how we can use them to improve Paikea.
The pictures below show Paikea formally known as Andromede before we purchased her, and half way through her front beam and longeron modifcations.
This new front beam arrangement we installed increases the stiffness of the front of the boat. The attachment points are no longer bolts but laminated into the hull structure. The longeron also improves the ability to increase sail inventory with the addition of inner forestay. If you would like to know more about the loads on our front beam and you haven’t seen our beam loads video you can see it via this link.
The Seagull Striker holds the Martingale strap in place. The Martingale is the strap of carbon that spans the front beam on a catamaran and helps distribute the load from the forestay.
Materials
- Front beam 2 pieces of ex – 2007 America’s Cup carbon fibre mast
- Longeron top section of ex – 2007 Americas Cup carbon fibre mast
- Laminating consumables
- Resin system Proset Lam 125
Finding our pieces
A good friend of ours was a key part of the administration team involved in the America’s Cup in Valencia. Since then, many racing campaigns regularly use his facility as a base to service and repair their race boats. He saw these beautiful masts being cut up and thrown away and had similar thoughts to us. Surely these can be repurposed and used again? His solution was to use them as fence posts at his rural property but he was kind enough to let us scavenge around and take a few pieces for our own project. The photos below show the pieces where we found them half buried in the dirt awaiting their new life.
Replacing the old beam and longeron
The first step was to remove the old longeron from Paikea. It was a pretty easy process to undo the bolts and take it off the boat. Next part was to secure the mast since we were about to remove the beam that held the forestay in place. We did this by attaching the main and fractional halyards to the front cleat of each hull. The mast head kite halyard and forestay were attached on the starboard side, while the jib halyard and fractional halyard were attached to the port.
Once we had the mast and forestay with the furler secured, we could glue in the longeron piece. This centre piece for the longeron was the top section of the Spanish America’s Cup contender Iberdrola. We used the deck of this same boat to make our hardtop. We cut the mast so that it was the correct shape to glue straight to Paikea.
We sat the new longeron piece on top of the old front beam and laminated the aft end of the mast section into place. As we had kept the old beam in place we could use this to clamp the new longeron piece to while we worked at laminating it to the boat.
The lamination of the junction of the beam to Paikea is shown above. You can see we also added some carbon plate on each side. This is not a structural part of the longeron, instead, it is part of our new trampoline net lashing points. You can see we also laminated the track for the trampoline at the same time.
Once we had glued the centre mast piece on it was time to remove the front beam. We supported the newly laminated longeron with a halyard attached to the end while we unbolted and removed the aluminium beam piece.
The carbon front beam was glued in two separate pieces. This was due to the fact that there were no salvagable pieces that were long enough to make one continuous front beam. Each side was done one at a time. We started by cutting out the hole in the inboard section of the bow to slot the beam section into. Each beam penetrates the front bow and is laminated to the inside outboard section of the hull.
Once we had fitted and glued into place, we could work on laminating the beams to the central longeron. This was tricky as keeping the beams in place while the resin cured without moving proved difficult.
Once we had glued the beams into place it was time to laminate the entire structure to the boat. As we were using a wet laminate technique we wanted to use a vacuum pump to consolidate the laminate. This requires some skill as you are not laminating a flat surface. In these videos we showed how we laminated around complex geometry.
Carbon Seagull Striker and Martingale
Materials
- Carbon fibre TP52 spreader cut to size for Seagul Striker
- Carbon Unidirectional for Martingale strap
- Laminating consumables
- Resin system Proset Lam 125
We recycled an old carbon spreader and carbon unidirectional fibre destined for the rubbish bin to make our seagull striker and martingale. The spreader was from a TP52 rig and could no longer be used as it had been damaged. It could, however, be used as a seagull striker for our new front beam. For the martingale strap we used many layers of carbon unidirectional cloth and handlaminated them to the shape we needed. We used lengths of aluminium extrusion we found lying around to create a mould to make the martingale and a broken carbon spreader was reinvented as an aerodynamic Seagull Striker.
As a side note – we do get some harmonics from the martingale but not much. If you are in the forepeak you may be able to hear the vibration on a windy day.
Forestay detailing
We cut slots into the longeron to fit the forestay toggle to the front beam. The pin we machined from some of the old nitronic rod rigging from our America’s Cup mast we had previously cut to fit Paikea. We did need to add extra reinforcing inside of the front beam at this point for added insurance and peace of mind. We then cut some nice covers out of carbon plate to lock the nitronic pin into place within the carbon tube.
