I picked up a used kit last year (Bic Rumba 150l (daggerboard) and a 4.5m3 UP sail) and while I wasn't able to get out last year, I made it out yesterday and will be doing more this year (as long as the wind is light enough to learn with). I know that this board is not an appropriate board to learn with, but it is what I have and I will continue to torture myself with it until I get better.
I am wondering what the best mast foot location would be for me to use. I have seen recommendations that farther forward gives a person more control of the sail, but what would you recommend? My skill level is that I am able to uphaul the sail and get the mast into the secure position, but I have yet to master turning around (hopefully the next time I go out I can do this).
Right now I have the mast foot about in the middle of the track; would I find it easier to push it farther forward at my limited skill level?
Thanks for your insight.
Select to expand quoteImax1 said..
Middle is good.
Youtube videos will help you understand how to turn around .
I understand the theory of how to turn around (tack), but being able to do it is another issue...
Oh, boy. This is a big topic to try and deal with on the internet.
The short answer is that the middle of the track is a good starting point.
The better answer is to go and type 'windsurfing' into google and you then do your own research to understand how a windsurf board works.
You can eventually come to understand how the centre of effort has to align over the centre of lateral resistance. We then shift the centre of effort forwards or aft to steer.
Or else you could get some basic lessons off a qualified windsurf coach.
Also a rank beginner here, and I would strongly second getting some coaching on this.
Unless you've got a background in sailing (and even if you do) I really needed the physical explanation to work through issues like that as there are a lot of different factors at play, as Basher said above.
forget about the "control" advice. that's more applicable to fully powered fast planning.
At this stage what you need for sub planning conditions is to be in the middle of the board so that the nose is just out of the water. Then leaning sail forward will turn you downwind, leaning it back will turn you upwind. If you sink the nose walking around the front of the mast, just shift the mast track back
Select to expand quotedecrepit said..
forget about the "control" advice. that's more applicable to fully powered fast planning.
At this stage what you need for sub planning conditions is to be in the middle of the board so that the nose is just out of the water. Then leaning sail forward will turn you downwind, leaning it back will turn you upwind. If you sink the nose walking around the front of the mast, just shift the mast track back
This^^^
stick it in the middle for now. Moving the mast base around comes later in learning when you can get planing.
Select to expand quotedecrepit said..
forget about the "control" advice. that's more applicable to fully powered fast planning.
Thanks Decrepit, I had a feeling that advice was for skill beyond mine at this point. Select to expand quoteAt this stage what you need for sub planning conditions is to be in the middle of the board so that the nose is just out of the water. Then leaning sail forward will turn you downwind, leaning it back will turn you upwind. If you sink the nose walking around the front of the mast, just shift the mast track back
Perfect, that makes sense, thanks again.
I just went out and looked at the board, and while the center of the mast foot track is not aligned with the center of the board (it is in front of that point), the front of the board is wider than the back of the board. Given this width difference, the center of flotation is going to be farther forward than the actual "center" of the board.
As a general rule, is the center of a mast foot track generally aligned with the center of flotation of a board? That seems to make sense, at least for my board, maybe it is similar with other boards as well?
Select to expand quotejonnycat said..
As a general rule, is the center of a mast foot track generally aligned with the center of flotation of a board? That seems to make sense, at least for my board, maybe it is similar with other boards as well?
Maybe for boards not designed for planning, just floating, but I have no experience with them.
Once planning it's a totally different ball game, the forces involved are quite complex, but basically, as you start planing the entry point moves backwards, the riders weight also moves back and the sail also gets racked back. The rails no longer have a big influence over lateral resistance, the fin takes more and more of the load. Until good riders reach the point where only the very back of the board is in the water.
So the mast position needs to be such, that the sail centre of lift, is very close to the riders harness. This doesn't have much relation to board buoyancy.
Middle of the mast track is generally good advice - but not in your case.
The Bic Rumba is a pretty ancient board, from a time when booms were much longer. You're using it with a pretty small sail, which means the boom is quite short, unless the sail is as old as the board.
To get things balanced, you'll probably need to move the mast foot towards the back - possibly even all the way to the back. When not planing, stand with the front foot in front of the mast foot, or next to it. If the board nose turns into the wind all the time, or the tail of your board sinks, move the mast foot forward until that stops.
Select to expand quotejonnycat said..
As a general rule, is the center of a mast foot track generally aligned with the center of flotation of a board? That seems to make sense, at least for my board, maybe it is similar with other boards as well?
Maybe for boards not designed for planning, just floating, but I have no experience with them.
Once planning it's a totally different ball game, the forces involved are quite complex, but basically, as you start planing the entry point moves backwards, the riders weight also moves back and the sail also gets racked back. The rails no longer have a big influence over lateral resistance, the fin takes more and more of the load. Until good riders reach the point where only the very back of the board is in the water.
So the mast position needs to be such, that the sail centre of lift, is very close to the riders harness. This doesn't have much relation to board buoyancy.
Thanks again, Decrepit. I got out on the water again today (did some tacks and gybes) and looked for what the nose was doing with the mast foot in the middle of the track, and sure enough it was lower in the water than the back of the board. I will put it a little farther back the next time I go out. Select to expand quoteboardsurfr said..
Middle of the mast track is generally good advice - but not in your case.
The Bic Rumba is a pretty ancient board, from a time when booms were much longer. You're using it with a pretty small sail, which means the boom is quite short, unless the sail is as old as the board.
To get things balanced, you'll probably need to move the mast foot towards the back - possibly even all the way to the back. When not planing, stand with the front foot in front of the mast foot, or next to it. If the board nose turns into the wind all the time, or the tail of your board sinks, move the mast foot forward until that stops.
Hi Boardsurfr, this is definitely an old piece of kit (I'm guessing mid to late nineties), and I am using a Bic Sport mast that is 4.65m in length (I am guessing this is the mast that came with the board). The sail itself calls for a 4.40 mast, so the top of the sail cap is extended by about 25cm to compensate for this. I also have a Bic 6.0 sail which I'm sure came with the board. As I mentioned to Decrepit, I will move the mast foot back from where I had it today, and thanks for the tips on what to watch out for to dial it in pre-planing.
