Twin fin fins: keels, uprights and hybrids by board type

Updated 2026-09-19

Twin fins split into three rough groups: performance uprights, half keels (also called hybrids), and full keels. The fin you want depends on the board's tail width, how far apart and how far forward the fin boxes sit, and how big or heavy you are. Twin fins are the largest fin config in the log, at 42-plus of 150 boards.

The three categories

Performance uprights sit close to vertical with the least area. They suit a narrower tail, a more pulled-in board, or a smaller rider. As at November 2023, the Alkali classic twin was named as a good pick for a smaller rider, while the Futures EN (a beige, larger-area upright) was named for a bigger rider or a wider tail. Channel Islands twin fins with a small trailer fin worked well on a performance twin in the same review.

Half keels, sometimes called hybrids, are the middle ground, and they are the category that works across the widest range of boards. Favorites named across two reviews (as at November 2023 and June 2024) include the Futures BMT (Britt Merrick Twin, designed for the Channel Islands Twin Pin, 23.58 square inches, 6.5 degree cant, 276 grams, about AUD 174 or USD 110), the Jim Banks Hooker (a long-based, swept-back fin built for Jim Banks' deep-concave boards), the NVS Ono keel and Ono convertible (G10, 6.5 degree cant), the Captain Fin Co Chris Christenson honeycomb hybrid keel (204 grams, the lightest fin in the June 2024 lineup, 5 degree cant, 24.18 square inches, about AUD 140 or USD 92), and the Soar Australia G10 half keel (311 grams, the heaviest in that lineup, 6.5 degree cant, 23.22 square inches, about AUD 230). The Soar was called the fin with the biggest sweet spot of anything tried, working on boards from a diamond-tail EPS twin to a deep-concave future-form board.

Full keels carry the most area and sit furthest back, built for wide swallow tails and boards that want maximum drive over pivot. The True Ames Hobie keel was named as a classic, large option for a very wide swallow tail or a big board. Glassed-on keels, which cannot be swapped, showed up on a 7'8 fish and gave that board drive and speed at the cost of turning as sharply as a removable fin.

Matching fin to board, from the log

A few patterns held across the two reviews:

• A wider, longer board with fins further apart generally wants more fin, moving toward a keel.
• A board with channels needs less fin than the same board without, since the channels act like part of a fin.
• The closer together the fins sit, the less fin area is generally needed.
• A stiffer, more forward-set fin like the Christenson honeycomb keel suited a fast, responsive board with thinner rails and a rounded tail.
• The Jim Banks Hooker was picked specifically for a future-form bottom with deep double concave and vee, where a regular upright or the S-Wings twin spun out.

Materials and cant, from the same boards

Fiberglass is the standard and easiest to reshape by sanding. Honeycomb versions of the same fin shape run lighter, useful for smaller to medium waves. G10 fins, built from a single laser-cut sheet, run thinner for their stiffness. A 6.5 degree cant sits a fin wider than a 5 degree cant, which affects both feel and how far out the fin tips sit when sitting up in the lineup.

Questions people ask

What is the single best all-round twin fin?

Across the fins tested, the Soar Australia G10 half keel was named as the one with the widest range, working on a diamond-tail channel-bottom twin, a future-form deep-concave board and an EPS diamond-tail twin alike. It is also the most expensive of the fins reviewed, at about AUD 230.

Do I need a trailer fin with my twin?

Not necessarily. A trailer, set behind the two main fins, adds hold and control on a more performance-oriented, narrower-tailed twin. Several boards in the log ran well without one; a Mark Richards style board with a very pulled-in tail was described as needing the extra control a trailer gives.

Why do some twin fins feel squirrely?

A twin fin with too little area for the board's width, or fins that sit too close to vertical on a wide tail, will feel loose and hard to control. Moving toward a half keel or full keel, with more area and more rake, settles that down.

Should I get FCS or Futures fins for a twin?

The single-tab Futures system has a far bigger range of twin fin options available than FCS, and the boxes hold a two-fin twin setup with only two attachment points rather than three. See FCS or Futures for the full comparison.

For the finer split between keel and upright, see keels or upright twin fins. For how rider size changes the pick, see fin size and rider weight. The two reviews behind this page are How To Choose the Best Fins for Your Twin Fin Surfboard and 8 Best Hybrid Fins For Your Twin Fin Surfboard. The full twin fin lineup sits in the current quiver.