Fig. 1
now full flap movement to off and more lift available sooner but ride height speed has now increased to 2, too much for a smooth ride height trim but still it doesn’t match the response speed of the cam which can be 3.3 when needed.
Sailing with the Bugs Cam On the water once the boat has been set up right all you need to do is adjust wand length to whatever ride height is desired and do a bit of rudder trim. On occasions I may tweak control rod length between races (just some fine-tuning, usually after changing between foils I just reset ride height trim to suit) but I now never touch it during racing… my boat is free of excess control lines. Downwind it’s really interesting to play
with the combination of wand length and rudder trim. If you keep the wand long and you are high you tend to use a bit more rudder to keep the boat planted. This pushes the bow down and the wand further back, meaning the cam follower starts to engage with the faster zone 2 with plenty of control action and feels OK. But if you shorten the wand to drop the
boat a bit more, then back off the rudder lift, the bow comes up letting the wand move forward so the cam follower stays on the ‘lower ratio’ and in very slippery zone 3 – it feels as if the wand is out of the water but it’s still in and active. This is the zone to target and downwind the control zones are there ready to assist when needed; remem- ber it’s the wand position relative to the cam zones that you should focus on. Sailing with low gearing is really very stable. With less reaction to waves it’s as
56 SEAHORSE
if the waves disappear and so have less impact on the boat. The reserves of lift control need to be close enough to either side of what we could call the ride height ‘platform’ and there ready to put the boat back on the platform only if it strays off it while gybing or dealing with troughs, or the backs of larger waves. The extra lift coming in strongly is also a benefit while foil tacking (badly in my case). I fitted the cam system to a bowsprit on
my own boat in a way that utilised the old control rod when the original wand was mounted on the side of the bow, but in testing I came to the realisation that I was getting some deflection in the new longer control rod and with that a loss of lift at critical times, which leads to misinforma- tion between the cam and flap. Upwind just when you need to be
pushing off good solid lift to stay in trim it fades and tempts you to dial in more lift than you need, then on occasions you have too much lift when the pressure backs off and the rod straightens; downwind the boat can press down too much and then rebound back too hard causing you to look elsewhere for solutions. I have recently refitted my boat as I had
always intended it to be done if you were building a boat from scratch, and the results were incredible – so much more stability with the boat doing what it’s being told; a good lesson in making sure that no matter what control system or foils you use any loss of lift due to flex in control rods, wands, flaps and foils cannot be tolerated. The big change was removing the old
control rod that came in on a slight angle from the bow side and fitting the new
‘service’ tube from the bow to the bulk- head lining up with the bell crank. The bowsprit tube now slides into this at the bow and is a very stiff attachment method. A new control rod of stiffer carbon tube now goes from the end of the cam follower straight to just before the mast stump (the adjustable wand control lines also go down this tube and into the cockpit, much neater), then it becomes a short section of 5mm S/S rod and passes through a 5.5mm hole in the mast stump – this acts as a midway low-friction guide. The end of this S/S rod is threaded into
another section of carbon rod that contin- ues to the bell crank connection fitting that is threaded in the opposite direction – this becomes the adjustable part of the control rod. Getting that sorted eliminated any loss of lift due to rod flex and keeps rod movement friction to a minimum. After this change I sailed with the same
cam and foil and couldn’t believe the improvement. As the boat was more stable without the lift changing under load I was confident to re-profile the cam with a larger ride height zone 3. This keeps the faster control gearing zones either side more distant to create a larger sweet spot of fast trim.
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