Gary,
I really like the euro-pin base extensions. They can get gummed up a bit with sand - though you can always fix it. I don't sail in places with lots of sand, and when I do, don't usually have too much trouble keeping it from getting gummed up (I usually try to take my whole kit directly from the water to the grass. If you think you'll be sailing in places where this won't be possible or easy, really wide sandy beaches, then you may prefer the US style. The euro-pin is easier to get the extension (and rest of the rig on and off) but, really, the US isn't that much harder in most conditions. The Euro-pin really shines when you're hands are cold or fatigued or both. Also, even though it's just a little bit easier, that can make a big difference if say, you tweaked your back during you session (happens to me some time). That being said, if you have to rig in a sandy place the Euro-pin might be jammed with sand,( rigging is the time when most sand gets in - once the sail is attached to the board it's not such an issue) then the US CUP might be easier whether it's cold or not,
The other time the small difference in ease of attachment detachment (US vs Europin) is if you have to attach or detach the sail and board while already in the water and not being able to stand. Euro pin is MUCH easier to do this with (some US bases and extensions fit with lots of slop - those are easier to attach too, but I don't like sailing with the slop . This comes into play at one of our local spots.
I don't think either system is better - it comes down to your needs and where you sail - cold water without much sand - euro pin will be a little easier - that little bit comes in during adverse conditions. Warm water with lots of sand - US cup probably a better choice. Cold water with some sand…. you may end up owning more than one type of base and extension.
As far as the one bolt or two, I think the one bolt is a better option for learning. Being able to slide the base forward just a little bit can make an out-of-control board skipping off the chop MUCH easier to control. Most of the guys that use the two bolt ones like to leave part of the base on the board because after years of sailing they have VERY strong preference for where the base belongs on a certain board and don't want it to move - AT ALL. They also probably have two or more boards for different conditions, and can cope with chop with major skill or by switching to an entirely different board. the one bolt ones sqrew on and can occasionally be loosened by your feet (accidentally while sailing). Most folks learn to avoid this, or learn to retighten it before it gets super loose. I think most people have had the experience of accidentally loosening the base with their feet, hitting a bit of chop and then while at speed, loosing the entire rig. If you're sailing on reasonably calm water, you may have to stubble to put things back together, have a good laugh and remember to check it in the future. If this happened to you in serious waves or shore break, it could be very dangerous and potentially lead to smashed kit. It could also happen in front of sexy bikini babes. For people unlucky enough for this to have happened in the latter two type cases, they probably swore off one bolt bases forever. For getting started though, a one-bolt base is most excellent - If you notice you're mast is moving fore and aft, tighten it down and try not to press your feet against the swivel tightener thingy so much.
The position of the base also helps determines the fore and aft trim of your board (moving it forward puts the mast pressure more forward and thus puts more of the board in contact with the water when you're planing - this keeps the board more firmly planted on the water for better control. If however, you can keep the board in control and keep the base back, less of the board will be in contact with the water, which will create less drag (less wetted surface area) and is ultimately even faster (if you can keep it under control). Way down the road you may be sailing waves were your base loosening up could be a mortal danger - until then you'll likely appreciate being able to easily adjust the trim on your board without tools and on the water. Moving the base can also help you tweak the center of effort (for different sized sails in relation to your centerboard, and later foot straps and fins (center of lateral resistance) - this can make it easier to get the board to point upwind or downwind - whichever may be presenting a challenge at the time.
For the extension length, I'd say buy a long one to start. You don't really know what your next sail acquisition will be. When it comes time to buy a new sail, you may end up having to buy a new mast, and potentially a new boom. These things end up getting purchased all at one time and readily add up. Even if you only need a short or medium extension now, if you get a long one, you can cover short, medium and long, which you may need in the future (and at which time, in addition to the sail you were planning on buying, you may end up having to foot the bill for a mast and possibly a larger boom as well.
I busted a Chinock aluminum extension once - it broke at about 12 cm and it was set to extend the mast 20 cm. A large wave and a sandbar were involved, and I feel very fortunate the extension broke as I imagine it would have otherwise been my mast. Windsurfing equipment is made pretty tuff, but it can't possibly be built to withstand all the possible forces that could end up acting on it (accidents, collisions, et cetera). Under normal sailing conditions how much extra force is an extension or mast subject when at a longer vs shorter extension? I presume a longer extension is built to handle these forces under normal sailing conditions (at least when the extension is new or undamaged). I weigh about 240 pounds and was a pretty aggressive learner (If I had good run going towards shore, I usually found out how shallow the water was by hitting bottom at full speed with my fin). For a long time a had a 520cm mast that I used at 38cm extension. I slammed that thing into every imaginable things I could (completely smashed the nose off a BIC 293D (which are made to withstand abuse) and also knocked some other chunks out of the rails. I'm less reckless with my gear now - but when I was learning I took so many hard falls without trying that it seemed silly to be careful at other times . I never had an issue with a long mast, highly extended, under normal sailing conditions including typical learning mistakes.
I bet a highly extended extension would be subject to more stress than a less-extended extension when loaded excessively in compression. Especially if simultaneously while being hit from the side (like if your rig gets slammed upside down (mast tip first) into a sandbar and your board, leg. or head whacks the extension or mast from the side at the same time while the board and wave are slamming down on your mast. I think this is what i did (though only moderately extended). If this happens to you, be grateful that you and any of your gear survived. In summary, I don't think highly extending a well made extension or mast should cause gear failure during normal sailing (excluding crazy crashes in large waves, shore break, or with other solid objects). HIghly extending a shorter than recommended mast to reach the recommend luff length on a sail may cause issues with the sail rigging and handling properly, but that's a different story. There are times when long extensions are appropriate, useful and as long as you don't clamp you're boom too low, safe.
As far as where the boom gets clamped to the mast - yes portions of the mast are built stronger for clamping a boom. If you tend to clamp your boom on the higher side, then you shouldn't have a problem with long extensions. If you're shorter and like a low boom, you'll want to be more careful with how far you extend your mast. Some masts have different graphics or weave patterns in the reinforced areas - others don't. Always use the least amount of pressure necessary to keep your boom in place, and if you use a skinny mast adapter with your boom, make sure it contacts the mast evenly, and that the boom head contacts the adapter evenly as well.
One more thing about extension - I picked up one of the North RATCHET type (2.0- the first generation had some issues with durability). They are a bit more pricey than other extensions, but, I'd say definitely worth it (Especially with larger sails or when tuning your downhaul (you can easily tune your down-haul (even on huge sails in the water, in deep water. Most sailors already have extensions that work well for them - in which case, I wouldn't necessarily tell them to run out and buy one. But if you ever tune your downhaul or use a rigging cleat, or certainly if you are thinking of buying a rig winch, and especially if you don't have ANY extensions at all, it's a great product. Most people adjust their outhaul from time to time on the water, but usually only tune the downhaul when rigging -then leave it for the day, or at least until they come off the water. The North Extension makes adjusting the downhaul as easy as adjusting your outhaul. Once it becomes this easy, you end up adjusting it as soon as you think it might help, and realize that, just like adjusting your outhaul, quick downhaul adjustments can make a big difference too. I'd strongly recommend this to anyone who does't already have an extension. I think I had to order mine from the UK. - still worth it.
Well Gary, you certainly don't jump into things half-cocked. I think you've inquired about nearly every bit of kit. That's wise …. just as long as you ultimately put all your new consumer wisdom to good use. …..I'm starting to suspect Garry isn't actually interested in learning to windsurf at all -he's conducting marketing research.
