|28 May 2013||Posted by Alex from Lagoon under Technical world|
Meir, a Lagoon 400 owner, asked me for advice concerning mast setting on his boat. So I took the opportunity to ask to one of the companies that prepares Lagoon catamarans in Vendée to summarize this complex operation. Here are explanations and recommendations by Yacht Care Services.
Modern cruising yachts use masts and standing riggings which look simplistic but require precise adjustment. The mast is an essential spar both in terms of performance and safety. It has thus seemed important to us to remind you of the proper masting process.
1 ° /
– The mast rests on two trestles, luff track down. We install all halyards and all electronic cables before mounting the rig (ensuring that all passages are free; attention to avoid crossing wires which should not chafe against other parts).
– We check carefully the halyard exits and passages of cables: remove sharp edges.
– We install the spreaders diamonds and the front martingale.
– We lubricate all turnbuckles!
2 ° /
Tensioning the diamond, the angulation of 20° to 25° spreaders induces a pre-bend of the mast. A high tension is necessary for the best lateral straightness. While tightening check that the spreader ends do not go down with the cables.
3 ° /
Adjust front martingale to straighten the mast and limit pre-bend to a half profile. Check all pins.
There are many ways to raise a mast with a crane. We see here a “header”. We remove all the air sensors (wind vane, anemometer … we leave the VHF antenna on but upside down). Attach the strap below the forestay attachment toggle and place a board with wheels under the foot of the mast so that it rises smoothly.
This rig type is common on catamarans. Its rake is rather important, so we need to ensure good contact between the base plate of the mast and the foot mast by raising or lowering the mast pre bend within ¼ to ¾ of profile. Beyond these limits, we will have to play with the forestay length to achieve a good contact. If the adjustment of the support is insufficient, we can also play very slightly with the front beam tension (+ or – 20 mm). Tighten the outer shrouds.
After tensioning the shrouds and securing the mast, we can climb to release the strap. We proceed to the installation of masthead sensors and control the lights. Going back down is an opportunity to check all rig elements a last time.
Few personal tips:
The basic setting of a catamaran mast is more complicated than a monohull. Indeed, a proper trimming depends a lot on the judgment and experience of the craftsman because no instrument can really measure the tension with this type of cable diameter. I strongly urge you to call a competent company to trim your rig.
To check if the settings are good: the mast should remain straight , without canting to leeward.
The leeward shroud can be a bit soft, which is normal. In this case, it should be secured with an elastic band to prevent it from swinging and weakened the rigid end.
More than words or pictures, here is a nice video of a Lagoon 450 masting edited by Thomas Rouzières from Yacht Care Services that you can contact here.