I've been using K4 Stubbies for quite a while now and I've been a big fan of them in my Moo custom quad. Recently I have been fortunate enough to have been able to test some K4 prototype Rocket fins. I got these from Steve in September to use in my trailer/twin Moo Custom.
The Board is 100l and 62 wide, and the prototype K4 Rockets were 17cm. So we are talking a big board and big fins.
I'd tried the board previously with some G10's so I was really keen to try out the new K4 Rocket fins.
First time out with them was at Gwithian, tiny waves that were really hard to find but cross off. First impressions were really good, significantly more lift from the fins than the previous combinations I'd been trying. It very much gave the impression of the board riding much higher out of the water. The tail of the board felt nice and solid and really felt like there was something to push against when trucking back upwind. Now when it came to screaming back downwind looking for a bit of a wave to wiggle at, the board behaved really predictably in the turn, and with a push on the back foot the fins certainly still released into a slide on the top turn.
Having used the K4 Rockets with 5.8/5.3 a few times I then got to try them full power 4.2 (could easily have been on 3.7) board and fins behaved beautifully, can't believe I could use such a big board with a 4.2 and still have so much control, drive and momentum with the K4's in place I didn't feel over finned once. I could drive frontside on board speed alone and not loose speed frontside. With my Hot Sails Maui Superfreak I am able to let the sail go neutral or reduce the power which in onshore conditions meant I was surfing the board to keep speed. Even with the big board and the 17cm fins I had complete control.
Having had the Big Moo and K4 Rockets for a while, I have been planning that much earlier using the Big Moo than I'd been used to. It got to the stage where I haven't used my Witchcraft Chakra 114, so it was time for a side by side test. Now part of this is down to the fact I have lost a little weight but I can be up and going just as quickly on the moo with a 5.8 as I can with a 5.8 on the Chakra, I think the extra lift from the Rockets in the trailer fin really helps in getting planning that bit earlier. I'd even gone back to the big G10 22cm centre fin in the Chakra and still felt I was quicker at getting planning with the 5.8 on the Moo.
Finally we got some more DTL Gwithian action and I got the pic below on the big Moo and K4 Rockets, stoked, the fins just drive off the bottom and through the top turn beautifully. Next step will be getting some to test in the Moo quad. I fear I am becoming a fin geek...
If you want to find out more get in touch with Steve Thorp at K4Fins