Originally Posted by Easyrider
The difference is that the sibs with speed tubes still have a centeral keel/hull-this is the part that causes the slamming in a chop.The Surfcat hull is a catermaran hull with a deep but thin sponson/hijacker either side of a flat deck-the best way to see the profile is to google an image search for "thundercat boat" or "zapcat" as these have exactly the same setup(slightly different profile though).
I should imagine that it is possible to add speed tubes, which will make it more stable at speed, but you will still get the pounding when out in a slight chop due the hull profile.
Hope this makes sence.
This is my Gemini 420 Surf/GRX at about 20-25kts on a flat day, no payload. Note how the base of the cat hulls are reinforced with a rubber triangular profile. The shape helps slice through chop.
As you can tell by my previous posts, I love this boat. Having helmed various SIBs and RIBs from 12-36ft, I haven't found anything that leaves me with the same smile at the end of a day on the water. No other boat I have come across combines the same single-handed practicality, speed, seaworthiness and payload capacity.
I bought this boat in 2003, primarily so that I could self launch from a surf beach, cross an exposed bay (11NM) and return safely at the end of the day. Bar a few capsizes (my fault, whilst playing in large surf with high onshore winds), it has proved to be a superb boat, capable of a significant amount of abuse.
It's now seeing use as a family day boat, a weekend expedition boat and a tow/safety boat for big wave surfers.
I will probably add to it with a Caesar Surfcat early next year (providing Caesar finally get back to me regarding whether they can produce the boat in hypalon). Expeditions around a few more of the UK's exposed coasts beckon in 2009!