Mast track for early planing

grantmac017 · Joined: 04 Aug 2016 Posts: 946

I've search for about two days to try and find something definitive or at least some theoretical knowledge with regards to mast base position as it relates to early planing and possibly pumping.
It seems that there are people who recommend just about any position and then offer a fairly poor explanation for why it works. Others simply say try it and see (do I need a single screw base for experimentation?).
Boards are an older 155l freeride 80x270cm and similar vintage formula 135l 100x268cm. Both being used with 9.5m 2 cam freeride sail and an objective of planing in light and gusty conditions with mixed success.

Any input from the brain trust would be great.

Thanks,
Grant

coachg · Joined: 10 Sep 2000 Posts: 3550

Mast track forward increases wetted surface of the board and decreases fin pressure. Mast track back decreases wetted surface of the board & increases fin pressure.

Early planing is all about board area (wetted surface) which is why wide boards plane earlier. Max speed is about decreased area which is why all speed boards are narrow.

You want to plane early, increase your board surface area.

Coachg

grantmac017 · Joined: 04 Aug 2016 Posts: 946

See that makes sense when you describe your reasoning. But then other sources claim it makes the board sticky and you should run the track as far back as you can control. Do I assume they are speaking of planing faster out of maneuvers in fully powered conditions as opposed to achieving plane in marginal conditions?

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

First, you ask a basic question, track location for early planing.
Then, you ask a expert question, final tuning for top speeds.
Two different audiences there.

grantmac017 · Joined: 04 Aug 2016 Posts: 946

NOVAAN · Joined: 28 Sep 1994 Posts: 1551

Mast track position is more about having you sail in a balance position in relation to sail size and line placement. larger sails have the center of effort farther back than smaller sails. Hence big sail forward and small sail a bit back. Get this set right and you have everything in balance. Makes for effortless sailing in the straps and harness and frees up the board to ride the fin...

coachg · Joined: 10 Sep 2000 Posts: 3550

Other than my Kona, mast track position is irrelivent to sail size. In onshore conditions I put my wave board mast base forward even with little 4+ meter sails to get out through the break. I plane earlier and longer water line slogs higher upwind.

Think of board area as airplane wings. Bigger wings get a plane flying earlier but limit top speed because of drag. Smaller wings require more power to fly but are capable of greater speeds because of less drag. That "sticky feeling" at the high end is earlier planing at the low end. Can't have both without on the fly adjustment like an F 14.

Coachg

jingebritsen · Joined: 21 Aug 2002 Posts: 3371

a dichotomy for sure.

base back until you get no bow wake splashing you in the face when hitting chop is my best shorthand response. another symptom of too much whetted surface: off the wind rail tripping or sudden arrest of boat speed.

fin large for conditions? base fwd, boom down, if needed.

fin small? base back, tend your boom height and lessen your draft with slightly more out haul.

PeconicPuffin · Joined: 07 Jun 2004 Posts: 1830

Mast track position is not a determining factor in getting you planing, though it can help you stay planing in marginal winds. For any given sail on any given board the optimal mast track range is going to be quite small...like 2-3 cm. I'm all about early planing, AND making subtle adjustments to my mast track position, but I never do it to get planing earlier. Mostly I keep the base in its "golden spot" (as found through experience) but I'll slide it back a bit if I'm on flat water and I'm willing to trade control for a teense more max speed.
As per Novaan, the position is fundamentally about balancing the rig against the board/fin.

Early planing is more about sail tuning (less outhaul for more pocket, but don't let the downhaul out too much...the sail still needs to vent) a bigger fin, and even more so: technique. Learn to pump, learn to stay still with your arms extended.

DanWeiss · Joined: 24 Jun 2008 Posts: 2296 Location: Connecticut, USA

Repeating others, mast foot placement on a planing board has nothing to do with getting in a plane per se. Rather, mast foot position must be a part of a balanced rig that keeps you planing with proper body position. After all, we all would choose to stay on a plane rather than be forced to repeatedly pump back.onto a plane only to fall off shortly thereafter.

As Ingbritson wrote, many factors influence mast foot location. Indeed this is true, as relief from a very "sticky" board may require running the base very far forward and raising the boom height when doing so. It all depends on your technique and gear.

Every board is different but a constant remains: planing best occurs at an angle of attack of 4 degrees between the board's flat and the water. Maintaining something close to 4 degrees for more often is the goal of mast bade location.