View Full Version : position of mast base on the board
2nd July 2008, 03:00 AM
I sail for some years already, but still did not find a good answer. on my F2 board there were marks of sail size - 6.4 forward, 4.5 backward. I therefore conclude that as the wind gets stronger the base should be shifted backward. Is this correct? what are the parameters and how they affect the base position? how to find the optimal setting for a certain wind/sea conditions?
2nd July 2008, 03:40 AM
Usually on the previous boards they come with a recommended base positions.
And I think that these are the best positions to put your mast base.
At the positions they find that the board works best.
Usually in choppy windy conditions you can lower your boom for extra control on the gears.
2nd July 2008, 04:40 AM
Ah, if it were only that simple.....
I rode F2 for quite a number of years (before Starboards came on the WS scene)
and I never could get the "move it forward for larger sails....back for smaller sails" to work.
There are too many variables that you need to balance for it to be a simple matter of moving the mast foot forward for larger sails and back for smaller sails.
Most boards have a "sweet spot" and to get the best speed and smoothest ride you need to keep the mast foot near that sweet spot.
But the "sweet spot" may move depending on the following important factors:
Sail size (and type of sail)
Sailing discipline( wave; slalom; freeride; freestyle; formula racing).
Many older race boards (racing longboards) had an on the fly/on the water adjustable
mast foot. If you raced, you quickly found out that putting the mast foot all the way forward to increase the waterline length of the board was very necessary to get good upwind speed.
Conversely, if you were on a reach or running downwind, moving the mast foot nearly all the way back was nearly always the "fast way".
So, now we have shorter wider boards, and no longer have an on the fly adjustable mast foot, so it becomes necessary to first find the "sweet spot" for a sailor of your size, with your rigs.
Usually it's best to start at (or near) the back of the mast slot.
If the board is hard to control, move the mast foot forward in about 1-2 cm (3/8"-3/4") increments until the board settles down.
Now you are "zeroing in" on the "sweet spot" (for you, with your weight/stance/rigs in your kind of conditions).
Once you find the sweet spot for a particular rig size on your board, try a larger rig.
Start at the previous "sweet spot" and work from there.
Often, you can move a larger rig forward a little and get slightly better performance, but at some point, you will get to a point where the board and the sea conditions get a bit out of balance and the board begins to "pound" into the chop.
Then you need to move the mast foot back a bit.
You will "search" for the perfect mast foot postions for your various sails and boards forever.
Mark where the sweet spots are, so the next session you don't have to start all over.
Make small adjustments as the condtions (windspeed, chop, tide or current developed chop, etc.) change.
You are looking for the best position for the mast foot that gives you "just enough" control that you scare yourself a little, but you can handle it.
If you settle the board down too much (by moving the mast foot forward of the sweet spot by too much) you will lose some speed and probably begin to encounter a hard (pounding into the chop, or a pound then rebound over the chop) ride.
If you keep the mast foot too far back, then you won't have the control you need to really "send it", and you will be backing off all the time to maintain control.
So, you have to experiment, and find out where you are "comfortably fast".
And, having someone else set up your kit may or may not be a good idea.
If they are more skilled, they will be able to make your board "too fast" for you to handle and you won't like it.
If they are significantly different in weight or height, this will affect where and how their sailor weight gets to the board, and again you won't like the way they have it tuned.
It's not because they didn't tune it correctly (they tuned it for themselves, obviously) it's just that you are a diffferent height/weight or you have a different stance and the whole package doesn't balance out the same.
So, enjoy experimenting. It's the only way.
Oh, and a common myth (since formula boards came on the scene) is that you can run the mast foot right at the front of the track.
This is true, if you are a formula racer, on true formula gear.
But formula racers need to get to the upwind mark first, and they will put up with alot of
"shenanigans" on other points of sail to get to that upwind mark first.
Also remember, when you are tuning, that mast foot forward often makes you board more "sticky" and will slow you down where as mast foot back generally frees up your board and helps it to be faster, So, you need to learn what "sticky" feels like, what fast feels like, and what lack of control because the board is too free feels like.
Then start "fine tuning".
Hope this helps,
2nd July 2008, 10:46 PM
Thanks for the detailed answer, which unfortunately leaves me uncomfort...
Compare these two cases:
1-20kts wind, 2-28kts wind (I encounter it a lot recently here). Same board AHD 265 90l, same sail NP ZEN 4.9 (no problem holding it and fly at 28kts!!), same fin 28cm slalom, same me 65kgs, 166cm high. Assuming I surf at the SWEET SPOT in case 1, what should I do in case 2? FWD or BCKWRD or none? or still no straight answer....
Thanks for the best answer I got out of all forums!!
3rd July 2008, 07:25 AM
If you are in full control of the rig, and the board begins to get hard to control, move the mast foot very slightly forward. This should calm the board a bit.
Or, better yet, change to a smaller fin and leave the mast foot at the sweet spot.
The sweet spot may change slightly as you change fins, and tune your rig for more wind, but not much.
It's all about balancing things out.
If you have more wind, use more downhaul and outhaul to reduce the power in your sail.
If you are having trouble controlling your fin (i.e. the board is "tailwalking" or you simply cannot keep the board going straight) changing to a smaller less powerful fin can make a huge difference.
Hope this helps,
4th July 2008, 12:28 PM
Roger and others -
Thanks very much for al the tips
12th July 2008, 09:56 PM
For what it is worth here's a contrary opinion. Try the positions suggested here and race a buddy that you know is approximately the same speed as you. Now change only the mast foot position and don't be afraid to try very forward positions. A forward position may add some wetted surface area and make your board a little more "sticky"; however, it may also reduce drag at the rear of the board and this may more than compensate for the added "stickiness", since you may plane through the lulls better and maintain a higher overall average speed. There's a fine line here with lots of variables - sail size, fin size and board size, sailor size, technique etc. just to name a few.
14th July 2008, 03:01 AM
Grant and others - thanks for the tips, I'll try them.
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