Fin Guide – All the basics you should know

Fin guide

Fin Guide – All the basics you should know

When you first start surfing you don’t need to pay a lot of attention to your fins. More often than not you surf a regular three fin setup also known as a thruster or tri fin setup. Even most softtops learning boards have a thruster setup. After that fins can quickly become a difficult topic. That’s why we’ve created the best fin guide to cover all the basics. More experienced surfers might already know most topics we cover.


Fin Guide – The basics

In general there are five key elements to each fin:

Base: The width of the base of the fin determines the amount of drive. Drive is the force that creates down the line speed. A wider base creates more drive than a narrow base. Fins with a wide base have a lot of drive, feel powerful and stable but are harder to turn. Less base width feels more responsive and easier to turn but offers less control. Shorter wider surfboards with less rail line benefit from a wider base.

Height: The height of a fin determines the amount of hold. In other words a higher fin sticks deeper into the water and gives you more grip. If you want to blow the tail or push a turn into a slide then you need the fin to release more easily. If you want to carve long arcs and like to feel engaged through turns then look for a fin with hold.
Note, less hold also means less drag so smaller fins are faster but offer less control.

Rake: The rake of a fin determines the length of your turns. The further a fin leans back, the longer the arc of the turn and vice versa. For beach breaks or vertical surfing look for an upright fin to allow sharp direction changes, ie. a loose feel. Fins with more rake are better for point breaks, larger waves and long fluid rail surfing – carvey feel. A surfboard for smaller waves or groveller will go better with a more upright fin, while a board for better waves can use a fin with rake.

Size: The size of your fin is a combination of the base and height together. A larger fin is taller and had a wider base compared to the same fin template in a smaller size. In general you select a fin to suit your weight, but this also comes down to personal preference, kind of board and the conditions. As a rule of thumb; a larger fin will give you more stability. A smaller fin will turn more easily.

Flex: Flex affects stability, drive and how lively a fin feels. The right amount has both powerful drive and springy release from turns. A stiffer fin is more responsive and less forgiving. A flexible fin is less responsive but also more forgiving. The flex is determined by the materials used to fabricate the fin.

Fin Setups

Thruster: The most common fin setup of them all. Also known as a tri-fin. These are the most stable and predictable, a good all round style and the go to for most shortboards, grovellers and surfboards designed to fit a range of conditions.

Twin: Although historically the Twin preceeded the Thruster, think of a Twin as Thruster without the stabilising back fin (but larger side fins to compensate). The result is a much looser feeling board, able to turn much more sharply with a single pivot point on each rail. Twins are especially good in small wave boards.

Quad: These sit somewhere between a Twin and Thruster in board feel. The lack of back fin makes them a bit looser than a Thruster, but the additional fin on the rail makes them very drivey. Quads are fairly versatile but especially suit fast, down the line waves and barrels.

fin guide i love surfing

Quad Rears: As the name suggests these are the two rear fins from a quad setup. Often, you can purchase these seperately to use create a quad setup together with the two side fins from a thruster set.

Tri-Quad: A 5-fin set that contains a thruster set and two quad rear fins so you can choose between surfing these fins as a thruster or quad.

ROAM quad rear fins
Quad Rears

Side Bites: Often confused with the quad rears because they are very similar. Some brands sell them as under the same label. Side bites though, are meant for a 2+1 setup like on longboards and mid-lengths. The biggest difference between them is that a side bite usually has a flat inside foil and a quad rear has a foil on both sides of the fin.

Single: A single fin that’s mostly used for longboards and mid-lengths.

ROAM Single Fin
Single Fin

Other factors that come into play for more advanced surfers

Fin Cant is the angle of the fin relative to the base. If a fin is perpendicular to the base ie. vertical, it has a cant of 0 degrees. More cant creates more responsiveness, less cant feels more powerful. This is something that you rarely have to deal with unless you’re a shaping or having a custom board shaped.

Fin Toe angle, or Toe In is the direction the side fins point in relation to the stringer or centreline. More toe in feels looser but adds drag. Less toe in is faster with less drag but is harder to initiate a turn. This also is something you rarely have to deal with unless you’re a shaping or having a custom board shaped.

Foil has a huge bearing on performance affecting lift, drag and flex.

Choosing the right fin for you

1. Choose the right size. There are several ways in selecting the right size, but in general the easiest way is to do this by the surfers weight. Most brands have a scale to guide you through the size selection. ROAM fins for example recommend small fins for under 60 KG, medium 60 – 80 KG, and large over 80 KG. FCS offers similar recommendations. Small under 65 KG, medium 65 – 80 KG, large 80 – 90 KG, and extra large 90 KG and over. If a brand recommends you to surf a large fin, you could alwyas still go for a medium fin to surf more loose or vice versa.

2. Choose your setup. Depending on the board and personal preference.

3. Choose the fin behaviour. Read the description of the fin and select a fin template on its performance or behaviour. For example, you can choose a nice all round template, a template for making longer and bigger turns, a template that generates a lot of speed, or a performance template.

4. Choose the right material. Depending on your level and wishes you can choose from different fin materials. A softer material provides more flex and a delayed response. A stiffer material (like carbon) has less flex and offers a immediate response.

That’s it…

for this fin guid about the basics. There is plenty more information out there and you can endlessly discuss al theories with your surf friends, local shop employees and shaper.

More detailed information about fins

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