The unit is capable of producing whole spars or spar sections of up to 121ft in length and up to 4ft 1in in diameter.

Current work in progress includes masts, spreaders, boom and poles for everything from 33ft yachts up to superyachts.

The company says it is also busy building production masts for Oyster 62s, 56s and 49s. The largest filamentwound mast recently delivered was for a Swan 86, while the smallest to date was for a Groupe Finot-designed 35ft race boat.

The process winds prepreg carbon yarns - tow-pregs - over a mandrel profiled to the internal size of the finished spar.

With the mandrel spinning between lathe chucks and supported by rolling belts over floating, pneumatic towers, the tow-pregs are run back and forth alongside on a saddle, which has the effect of interlacing them over the whole length.

The winding process can effectively lay the filaments down anywhere along the mandrel at anything from ±5 degrees to ±90 degrees; the angle determining the combination of longitudinal and hoop strength.

"The machine can lay down material at about 20kgs per hour, " says Mike Orange, Hood's technical chief, "and will, typically, wind a 30 metre spar in about four days."

Orange says the company is currently using T700 12k carbon fibre with epoxy prepreg at 70% carbon to 30% resin by weight.

After oven curing at 120infinityC, the finished spar is slipped off the mandrel and lacquered or painted as required.

Hood says the strand by strand process gives "fantastic" consolidation of the laminates and eliminates any possibility of tucks or voids within the spar walls. The process at 60-70psi, they say, is the equivalent of 75% of autoclave pressure and exceeds standard vacuum bag pressure by four to five times.

The finished weave can also have additional prepreg reinforcements added undirectionally or to boost hoop strength. So spinnaker poles that need some degree of impact protection can be sheathed with aramid reinforcements, such as Kevlar or Twaron According to composite design engineers, High Modulus - which acted as consultants during the project - the design performance parameters set for the first spar, for an Oyster 62, were exceeded by 16%.

Hood Yacht Spars is also currently experimenting with the machine to produce composite rigging and complementary rigging components, although curing carbon shrouds may, according to HYS president John Boyce, have to be done in vertical ovens.