James Boyd Photography /www.thedailysail.com

New Hollom-designed International 14

Proud owner and designer tell us all about it

Wednesday March 24th 2010, Author: James Boyd, Location: United Kingdom

For a supposed development class like the International 14, new designs are something of a rarity. However Composite Craft in Cowes are now marketing a new design – or a new hull at least – from one time America’s Cup designer, Dave Hollom.

Composite Craft used to build the dominant Bieker 5 design but having worked with Hollom on building some new rudder T-foils three years ago, last year committed to build his new hull. Hull no1 was built on spec, but has since been acquired by present Merlin Rocket National Champion, Glen Truswell, who’s day job is working for LaserPerformance as their Technical Project Engineer.

While the new boat – distinctive (to put it mildly) with its hot-rod ‘Pimp My 14’ paintjob – has a deck from an existing mould Composite Craft had, the new hull shape represents an entirely different approach, with a V-section in the middle of the boat tapering out aft and morphing into a U-section at the bow, with the aim of achieving a higher prismatic co-efficient and less wetted surface area.

“The U-section enables you to get a higher prismatic without making the bow too bluff – you’re putting volume into the ends,” explains Hollom, for whom this is his first 14 design. “If you read William Proud’s famous experiments he reckoned the place to put displacement was low down in the bow away from the water surface and high up near the water surface at the stern – hence your typical powerboat hull with a deep forefoot and a very flat stern.” He says he has tried it successfully in the past on model yachts - one of his specialities.

Composite Craft’s Bob Preston enlightens us some more: “The theory behind it [the U-section bow] is that you are getting a lot of lift on your rudder T-foil that’s pushing the bow down, so you are riding on the bow a lot more. The V-section at the daggerboard area is to reduce the wetted surface area and so when it heels over it picks up stability. So stability at rest is less, but as it develops lift it picks up stability.”

Like other contemporary 14 hulls, the Hollom design is “spot on” the International 14 rule’s rise of floor measurement point half way along the hull and this is where the chine ends.

Of course it features an inverted T-foil rudder and this follows the same thinking as the lifting rudder foils Hollom conceived 2-3 years ago. Uniquely (when it was introduced) the lateral, lifting element of the foil is mounted half way up the height of the rudder but on its leading edge.

Hollom explains: “You are producing lift at the back of the boat, which is giving you a bow down pitching moment, so you have to move the crew as far aft as possible. But if you could move the crew further aft you could have more up force on that [the foil]. The limiting factor fact of how much lift you can get from it is the fact that you will nose dive or you won’t be in an attitude to plane if you have too much on. But the further forward you move that fin is akin to moving the crew aft, so you are able to work it harder if you put it on the front [of the rudder] rather than the back.”

The profile itself has a straight trailing edge and an elliptical leading edge. “Essentially it comes from model aircraft technology. We also design model glider foils, and it so happens that the Reynolds number that the horizontal foil on a 14 runs at is about the same as an F3B competition glider,” says Hollom. The section was also used by Jo Richards on his successful Dead Cat Bounce Nation 12 (which Composite Craft have also taken into production), although, ever the innovator, Richards cut it in half and swept it back... We understand the lateral foil is quite flexible and this should help prevent it stalling out.

On the build side the rudder was made in pre-preg and made in Composite Constructions’ new C&C machine.

There are some other new features such as the rack arms which are a carbon fibre, tapered aerofoil section with the shrouds taken out to them (like the Bieker 5).

Glen Truswell masterminded the on deck fit-out and the boat is now at the ‘more complicated’ end of the International 14 spectrum in terms of its sail and rig controls, Truswell admitting that part of his inspiration for this came from long term 14 sailor and Hyde Sails boss, Mike Lennon (who likes a string or two...) “His advice to me was that you’ll want all the same adjustments that you’ve got in the Merlin Rocket,” says Truswell. “The boat I have doesn’t do anything the Merlin doesn’t in term of lowers control or rake control, led out to the side of the boat. His advice to me was that it is even more imperative to get those things right with the 14, because even if you don’t use them all the time during racing, you’ll find them a very valuable tuning aid, to hone in on your fast settings in the first instance.” He adds that the large amount of cordage is perhaps more evident on the 14 because the cockpit is so much smaller and shallower than the Merlin.

The kicker strut is designed so that the take off can adjusted increasing room in the cockpit for the crew. The boat also features a daggerboard lifter and downhaul, allowing the board to be lifted up partially to reduce drag once a maximum warp factor upwind and lowered again easily prior to tacking.

The jib is self-tacking, nothing new there, but the track forms a shallow W-shape in order to maximise jib area.

The new hull costs £13,500 and fit out can vary greatly on top of this.

Newbie 14er's perspect

Glen Truswell says he is moving into the 14 now because he won the Merlin Nationals last August, after 15 years of trying and wanted to get into a boat that was a “bit more lairy” before he got too old. “I’m always very interested to do World Championships when they are coming to the UK and with the 14s coming in 2011, it seemed like a good point to get a boat and sail it for 18 months and to be part of a massive GBR type event and to enjoy that.”

During the change he is now sailing with a new crew in RYA High Performance Manager, Chris Blackburn, with whom he finished third at the SB3 Nationals.

He went for the Hollom design partly because it was something new, but also because the shell was already complete.

The new 14 went yachting for the first time last weekend in Poole Harbour. Not only was it the boat's maiden voyage, it was also Truswell’s first time in a 14. “The boat performed exceptionally well – we’ve already managed 12.5 knots upwind in it, which I believe is pretty competitive. No breakages at all, which is quite good for a 14 first time out I gather,” he enthuses.

Stepping up from the Merlin, the 14 is obviously narrower and more tippy, but the most daunting feature was the rudder T-foil. In this respect Truswell says they were fortunate because they quickly found its ‘neutral’ setting, which he understands can be a problem when setting up a 14 fresh out of the box. He has heard many nightmare stories of what can happen when the lifting foil is not aligned properly.
“You have only got so much throw and travel in the system so we were very lucky that when we measured it up and made a guestimate based on a bit of experience, we found that we managed to tune the foil right in the middle of the range straight off. I’m sure there was some luck involved there.”

With the foil in its neutral position he says the only give away was how clean the wash was coming off the transom and the smooth transition between planing and non-planing.

In the second half of the training session they started to crank on some foil, creating lift at the stern and impressively the GPS read-out showed them to be 2 knots faster upwind...

“We were hitting 10.3-10.5 knots upwind in the first session and as soon as we started to go into lift mode, the bow started looking less like a Fireball – bit bow up and slapping along - and a bit more bow down, more like a Merlin, the bow just kissing the surface of the water. We saw the GPS jump up by 2 knots, which we thought was absolutely astonishing.”

Downwind without any foil they had found the boat was losing some directional stability as the bow passed through waves but by using the foil to trim the stern down fractionally it released the bow and alleviated this, making it much easier to steer downwind.

“It is a very fine tune adjuster [for the foil] we have on the boat, which is brilliant because it is very well geared and there is a lot of purchase, but to adjust it significantly is quite a few turns,” says Truswell. “We have gone for a very compact little gear box on the front end of the tiller arm, it physically is a gear box with bevel gears and a worm drive rather than a string system.”

According to Truswell, the boat’s first competitive outing is likely to be the Weston Open on the second May bank holiday weekend. However he will be spending most of this year training in the boat down in Weymouth. “There were so many things we were doing wrong in terms of the manoeuvring of the boat, the set manoeuvres, it is very transparent and very easy to see where you need to be and what you need to be doing right, which we are not doing at the minute so we are just going to continue to train on our own in Weymouth and maybe encourage one or two other boats to come down and boat tune against us.”

Latest Comments

  • 769117 25/03/2010 - 03:58

    HHFS. I wonder what the late great Stewart Morris would have had to say about this. Maybe Stuart Walker would like to comment. Bob

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