by Doug Pemberton

When I first started wearing the Pro model Force Fin three years ago I endured several months of chuckling and snide comments about my funny looking new fins. But I found them to be very comfortable, providing me with all the power I wanted without any leg fatigue. Since DIVER Magazine first covered the Pro model Force Fin (May 1994) they have become increasingly popular at the dive site and those who laughed the loudest have been converted. But now we have the Extra Force Fins, the next generation Force Fin, bristling with the latest in hydrodynamics including adjustable whiskers and vortex generators. And now again, I'm hearing "What the heck are those??!" and "So, can you pick up Tokyo on those things?" Yeah well, sticks and stones...

Extra Force Fins, the result of seven years of research, are made from a Uniroyal chemical liquid-cast prepolymer, the same material used to make the translucent Tan Delta Force Fin. This compound has excellent memory and like all other Force Fins will always maintain it's shape. The Extra Force Fins retain the open heel and toe design and trademark fish tail shape but the blades are longer, narrower, thicker and stiffer than those on the Pro model Force fin, giving the Extra Force a little extra "snap", which is one of the properties that gives the Force fins their power.

At the ends of the Extra Force blades are two spoilers or whiskers which can easily be turned inwards or outwards to direct the flow of water over the blade of the fin. The whiskers have four settings which I refer to as first, second, third gear and overdrive. The presence of the whiskers ensures that more water is channelled off the end of the fin rather than being spilled off the sides. By turning the whiskers inward the flow of water is directed towards the centre of the fin and thrust is increased as the channelled stream of water creates a ram-jet effect. For normal diving the whiskers can be kept aligned with the outside of the fin or moved one notch in for first gear but if extra power is needed, then second, third or overdrive might be required.

The bottom of the fins are as different as the topsides. A series of bumps adorn the undersides and, no, these are not cleats for golfing, as some have suggested, they are vortex generators. The idea is that they create water turbulence and assist in breaking the resistance of the water, thereby reducing the effort during the upstroke.

One of the smaller changes to the Force Fin is that there is now a choice in heel straps. A new elastic cord with a padded heel piece can be substituted for the familiar webbing strap.

Overall, I liked the Extra Force Fins. As with the Pro model of the Force Fin, they take a little time to get used to. Due to the reduction in resistance with Force Fins, some divers have commented that they didn't feel as if they had the control compared to their regular fin but this is quickly overcome after a few dives. The Extra Force fins offered noticeably more resistance than the Pro model and the resistance increased as I moved into higher gears but they were very comfortable and still gave me all the power I needed without any leg fatigue.

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