I have sailed cats and trimarans all my life and the SeaCart looks absolutely cool. Can anyone provide a first-hand account in regards to speed, stability, overall experience? I may look into buying one in a few weeks.
Welcome to sailnet. I'd highly recommend you read the POST in my signature to help you get the most of your time here.
That said, the Seacart 30 is one of the few small trailerable trimarans I haven't had a chance to play on. However, it really depends on what you're looking for in a boat. If you're looking for an out and out racing machine that is designed for sailing with four-to-five people... the Seacart 30 is probably a good choice.
Also, unlike the Corsairs, Dragonflies, and Telstar 28, it is a demountable rather than a folding design, and as such will require more work to trailer. Currently, AFAIK, there are less than 20 built world-wide. So finding one to take a test sail on is going to be rather difficult.
However, if you're looking to go cruising for a week, it is probably a pretty lousy choice. Like the Corsair 24, 28, it doesn't have standing headroom down below. In fact, the interior on most Seacart 30s, from what I've seen, is basically unfinished. There is no galley, there is no head, and the accommodations are primitive at best.
It really depends on what kind of sailing you want to do. The Seacart is probably far more likely to capsize than say the Telstar 28, due to it being designed as a near pure racing machine. It has a much higher sail area to displacement ratio.
To give you an idea, let's compare it to a cruising trimaran of about the same size. The SC30 weighs 2090 lbs. excluding crew weight... and it has 645 sq. ft. of sail for upwind use. The Telstar 28 weighs in at over 3500 lbs, has an upwind sail area of 525 sq. ft.—and is considerably more stable IMHO. The Telstar 28 also has a full marine head, with holding tank, a full galley, and standing headroom of about 6' for most of the cabin.
Another point working against the Seacart is the price... as a pure racing machine that has to be imported from Sweden, it is going to be fairly expensive, especially given how weak the dollar is at the moment. The price according to one website for the Seacart 30 is $224,000. That is over twice the price of a fully kitted out Telstar 28.
BTW, I've gotten my Telstar up to 15 knots without trying.. and we normally sail at 9-12 knots without a problem, often in 7-9' seas.