K4 Fins Review

K4 Fins Review

K4 fins is owned and run by intrepid vagabond wave warrior Steve Thorp. Hailing from the middle of England (Leicestershire) you’d be forgiven for thinking that the chap got hardly any water time – and yet you’d be mistaken. Thorpy clocks up more hours travelling to where it’s firing than most people have hot dinners.

Steve Thorp @ Fistral – pic courtesy Ricard White

Steve also happens to have a stake in a plastics company and it was only a matter of time before he started pressing out fins to be fitted to his arsenal of wave slaying equipment.

A few months ago Loco stand up paddle boarding announced that all Loco sticks would be coming equipped with these mellow yellow foils. But how do they actually stack up? We got freelance watersports journalist, Tez Plavenieks, to do a little write up based on his experiences. Over to Tez for the goss…

Fins – those things in the bottom…

Most wave riders (of any craft) will no doubt tell you exactly what they expect from their vehicles of choice. In fact nearly all stand up paddlers will have an exact picture in their mind’s eye of how they want their paddles to perform as well, and yet, ask the majority, and they probably couldn’t tell you a lot about fins.

K4 14″ 

The topic of fins is actually a minefield, which may go some way to explaining why SUPers tend to avoid the subject.

Man walks into shop with defined knowledge of what stick he wants, discusses performance attributes, hands over readies, walks out of shop, gets new board wet – hardly gives fin set up a second thought.  Sound familiar?

Worth a thought

Stock fins, for most SUPs are usually very good. They offer a decent level of performance and will most likely be well manufactured. But chances are SUP surfers won’t be getting the most from their equipment until they switch something up.

Changing your fins can be the easiest way to improve your stand up paddle board’s rippability and overall performance. Likewise, it could kill it all! The point is though, you won’t truly understand your set up until you start tinkering.

As a rule of thumb smaller fins will loosen up your SUP while bigger fins will improve grip. You can start getting really techy by chatting about fin placement, angles and flex, but to keep this simple, we’ll just talk about size.

K4 SUP fins

One big difference between Loco stand up paddle boards and many others is that Joe Thwaites (Loco boss man) firmly believes in providing wave sliding toys with the proper foils.

Rather than go too big, he believes that all boards should be sold with optimised fin sizes which is why for most high performance Loco surf SUPs you’ll end up with 14”s or 16”s – depending on the size of board overall and weight of rider.

Mellow yellow, K4 fins

A 14” central fin with 10” side bites will give a super maneuverable stick that loves being squirted into full power tail slides while a 16” middle foil, with 12” side skegs, will hold more through turns and give a drivier feel. (You can of course change the size of the side skegs as well, which will also reveal even more performance characteristics).

Obviously rider weight also makes a difference and heavier paddlers will be best served on the bigger types. If things aren’t quite working for you then trying one size either up or down should reveal that best fit.

K4 fins come in a variety of incremental sizes and the perfect combo is available for you.


The conditions for both sets of fins was between knee high and head high waves with everything from off shore to on shore junk.

Three different Loco stand up paddle boards were used for the purpose of reviewing the K4 fins – an 8.11ft, an 8.4ft and 7.10ft. All three boards feature slightly different volumes, tail widths, lengths and feel, but inherently are what many paddlers will be riding in the surf. (Loco’s 9.5ft is also worth a look for heavier riders or progressing intermediates).

Tez checking out the spray chucking potential – pic Tez

The two sets of K4 fins were swapped between all three sticks with two riders from both the mid weight and light weight spectrums testing them out.


Both sets of K4 fins work well depending on your SUP surfing style and feel you’re searching for.

I actually found myself going to the smaller set most of the time. The K4s all grip extremely well and can hold a full rail speed blur bottom turn without too much trouble. Coming back up into the throwing pocket was fluid and smooth with just a small amount of pressure needed to push a load of spray into the sky.

For those who prefer a more skatey sensation, then stamp on the tail a little harder and the K4s release, fins break free and you slide for miles.

Sticking the bigger foils in the box I found helped loads when conditions were less than perfect. With an onshore breeze and bumpier wave face the added length meant that spin out was avoided and smoothness remained.

Our lighter tester (56kg) checking out the K4 fin set up – pic Tez

While not being quite as loose as the smaller K4 fin set, the bigger sizes were equally as impressive in performance and were my go to junky wave skegs. Bigger riders may appreciate the added grip and drive.

Summing up

Both the 14” and 16” K4 fins are top shelf fin set ups that will see you ripping on your Loco SUP. Depending on the sensation you’re looking for will ultimately dictate what size you choose.

K4 fins – getting section with Loco SUP

If you’re struggling to decide which fins are best then give the guys at Loco a call and they’ll point you in the right direction.

Get sectioned with Loco and K4.

K4 fins are available to buy direct from their online shop. You can check out the full Loco stand up paddle board range by visiting the products section.

Tez Plavenieks is a freelance writer who loves windsurfing, SUP, surfing, snowboarding, drums, art and beer. If he’s not out sliding sideways then you’ll find him producing articles, stories and content revolving around his passions. Check out more at www.tezplavenieks.com