RE: Starboard Carve 145 Set Up (noob)
Welcome to the Starboard Windsurfing School!
Glad you f0und us.
OK, I'm guessing Eastbourne is in the UK, correct?
Are you sailing in a freshwater lake or in the sea?
This makes a little difference as the board has more floatation
per liter in salt water.
Now let's get down to some "parameters" so we are all speaking in the same terms.
12 Stone is 76.2 Kg. or 168 lbs.
That's not real "heavy" as far as windsurfers range of weight goes, so you are pretty much a "middle weight" sailor.
This is good as you will find that the Carve 145 may be a little less stable than whatever 175 liter board you've been learning on, especially if the 175 ltr is wider and has a wider more squared off tail.
So, let's discuss your questions one at a time:
1-What difference does the size off fin make and how do I choose an appropriate one?
For sails in the 6.0-8.5 m2 range, the stock fin (normally about a 48-52 cm freeride design fin) should work nicely.
If you use sails larger than 8.5 m2 you might want to upgrade the fin size (use a longer span (length) fin) to achieve a better balance between the sail size and the fin size.
If you choose to use smaller sails (< 6.0 m2) you may want to drop down to a 44-48 cm fin as this will "balance" better with smaller sails.
For a board as wide as the Carve 145, there is a limit as to how small a fin you can use as at some point you will be riding "on the fin" (not at your current skill level) and having the correct fin size can enhance the overall performance of your board. But, as sails sizes are changed, fin sizes also need to change to achieve a balance.
If you have very shallow water, or sea grass (weeds) you may need a shallower fin with more fore and aft surface area.
For simply shallow water, there are "wide chord fins" that give more area.
For weeds and sandbars, a good weed fin is both shallower, sheds any weeds that wrap around the leading edge (LE) of the fin, and provide a bit of a safety feature as they will "ride up" over sandbars, giving you a less abrupt "stop" and limiting any potential for damage to sailor/board/fin.
2-What size/type/make of sails do you think I need to get me going?
What size sails you need is very much "linked" to the amount of windspeed you are dealing with.
Board size can also be similarly "linked".
The more wind you have, the smaller the sail you need and pretty much the smaller the board you can sail efficiently.
I'd think, at your weight, that a 7.5 m2 would be a good starting point if you have wind in the 12-16 knot range.
If your windspeeds are < 12 knots, you will need a larger sail to be able to plane.
If your windspeeds are > 15-16 knots, then your 7.5 m2 rig is going to start feeling a little large and a 6.5 m2 rig would be better for sure.
If the 5.8 m2 sail you've been learning on is an older design, you can most likely get away with a 6.5 m2 rig.
Any rig larger than the 5.8 m2 you are accustomed to will seem large right a first, but you will quickly adjust your sailing technique, and I feel it's better here to have a sail that you can definitely "plane" on.
3-If I bought a 50/75% 460 carbon mast can I rig all size sails or do I need a smaller one for smaller sails?
Masts are categorized by both the length and the bend characteristics (IMCS/MCS).
Smaller sails use shorter and softer masts as this is what they have been designed on.
If you only want to get one mast, look for a good 75% min. carbon content 460 cm IMCS 24-26 mast as this should fit sails in the 6.0- 7.5 m2 range, and you will have a mast with the appropriate bend characteristics for the sails. This gets the most performance and value from both the sail and the mast.
Try to get the highest carbon content you can afford, in the "recommended best" size and brand of mast for the sails you are using. It should be printed right on the sail or the sail bag what the "best" mast length and bend characteristics (MCS/MCS numbers) are.
4-Is there any difference in UJs or will any do the trick?
While the "function" of the various types (rubber, polyurethane tendon,
mechanical) is pretty much the same, you will need a good solid joint that will ensure that your rig stays attached to your board.
UJ's is not a good place to save money. Get a good one. Your life could depend on it at some point.
I prefer the polyurethane tendon joints as they seem to last the longest are are very bombproof and secure.
Whether you use a Chinook (2 side release pins) or a Euro Pin (single metal pin with a locking device up inside the mast extension is completely up to you. I would check with other sailors in Eastbourne and see what they are using and get something similar.
You will for sure need a "mast extension" so you can set the extension to give the correct mast length for various sails.
Better to have a couple of these in different sizes so you can cover a wider range of sails without having a lot of very stiff mast extension up inside the bottom of the mast. On some sails, having too long an extension "stiffens" the bottom of the mast and can cause lower batten rotation problems. Also, if you have more than one, you'll have a "back up" that will get you back out on the water if something breaks oe gets left at home.
5-Can I rig a smaller sail on a larger boom or do I need several different sizes?
You should be able to find a boom that will cover the range from round 6.0 m2 up to 7.5 m2. For larger sails you will need a longer boom, and for smaller than 6.0 m2 you will need a shorter smaller boom.
6-How do I know where to place the UJ ie front or back of the slot and what difference does this make?
At first, I'd suggest placing the mast foot in the center (fore and aft here) of the mast slot in the top of your board.
If the board doesn't balance well with the mast foot in the center (i.e. it tends to head upwind all the time, or downwind all the time) up can move the mast foot to compensate to some degree.
If the board always seems to sail upwind, move the mast foot forward a bit and see if this helps. If the board always seems to want to sail more downwind, move the mast foot back a little to compensate.
What your are doing here is applying the "pressure" (force) from the rig a bit more forward on the board (and further from the fin) to push the nose away from the wind.
If you move the mast foot back, you are putting less pressure on the nose of your board and applying that pressure closer to the fin.
There's quite a bit more to this, but at your level, perhaps the simple explanation is better.
Hope this helps,