FIRST, THE SPELLING. I thought the word was Accelerating but these are definitely Excellerating.
People who own Force Fins love them. They swear by them, in fact. When we equipped our Price-No-Object diver recently (The £11,000 Diver, December 2007), we featured a pair made from Tan Delta material. This translucent coloured polyurethane makes for a very sexy piece of avant garde sculpture that you'll enjoy running your hands over.
Each pair of Force Fins is moulded under the eagle eye of sculptor Bob Evans in California. The material he uses may account for much of the whopping retail price, but it's almost indestructible. Fins in Tan Delta may put you in mind of wine gums, but they don't melt in the mouth, because the material enjoys a 100% rebound from deformation.
This is significant, both when packing them in a bag and using them in the water. These fins could last you a lifetime.

Foot Pocket
There is no foot pocket as such. Your foot fits through an integrated stirrup so that there is no loading on the toes at all. The effect is to leave the fins looking a little floppy on your feet.
The underside has some raised dimples to reduce slipperiness on a wet deck, though they are not as effective as a slab of grooved rubber for walking on.
Remember that these fins are intended for use by both barefooted divers and drysuited divers with big boots. My feet demand XL when they're in a neoprene sock, but XXXL when I use a drysuit.
As it was, these Force Fins were such a snug fit after 45 minutes of finning that I had no hope of getting them off in the water, and because they were so slippery I couldn't stand on one on deck while I pulled my foot out of the other.

The blade shape is quite narrow, yet these fins get their rigidity by being progressively thick. They have the characteristic Force Fin fishtail and gentle fixed scoop.
The little raised dimples on the underside are what Bob calls vortex generators. These, he claims, cause micro vortices within the water flow across the blade, reducing turbulence and allowing the water to slip by easily, so accelerating the water-flow over the underside of the fin.
He copied the idea from the small bumps on the upper surfaces of the humpback whale. Whales seem to get through the water OK, though no one ever said they were that good on the deck of a boat!
On the downward kick side of the blade, you notice what Bob calls whiskers.
You can adjust these using a hexagonal wrench to tailor the performance of the fin to suit you. They can be set wide for a gentle effect or pulled together to give plenty of thrust.
Before I could even get near the water with them, Bob had sent me a pair of his latest bat wings. These replace the whiskers, which look a bit like ailerons, with something akin to massive twin tail-fins or keels.
Evidently, he first made these bat wings for Captain Billy Deans, the Florida technical diving pioneer, so that he could frog-kick more effectively with his Excellerators. They are quite flexible. Bob says they offer maximum thrust vectoring. Thats what I want. I set off to try both, knowing that I had two weeks aboard Royal Evolution to determine the best option for me.

Straps & Buckles
A simple elastic strap holds the fins in place when youre out of the water, but Bob assures me that the more you fin, the more the fins are pushed onto your feet, rather like the propeller of a boat screwing itself onto its shaft.
I believe him, but it would be upsetting to lose one, considering the cost of replacement alone.

I had intended to start with the whiskers set somewhere between the widest and narrowest settings, but I ended up pulling each pair of whiskers together during my first dive with them, to determine the level of thrust with which I felt comfortable.
My buddy, not realising that I was trying to get a feel for them, said he was fed up with me zooming away and then zooming back again.
As with the regular Force Fin Pro, I had to use a rapid flutter-kick for best effect, slightly out of character for someone with my long lazy legs.
I lent the fins to fellow passenger Ricky Owen, a regular split-fin user. He felt they were excellent in a current, and if you wanted to get going.
Next, I switched to the bat wings. They looked remarkably silly and drew some humorous remarks, but in the water I could feel the water being thrust behind me in a whoosh as I finned vigorously and powered forwards.
The bat wings were far more appropriate to my habitual long-legged finning technique, and I felt I could take on the most powerful of head-on currents, though at some cost in the form of ankle-strain.
I canvassed further opinions. Dive guide Simon Gardner, an avid Force Fin Pro fan, agreed with my conclusion. The other guide, Hesham Ayyad, thought the fins felt very powerful but found them uncomfortable.
Passenger Hugo Cariss said he could feel how effective the fins were, but it took him a while to get used to them.
He likened them to surgically enhanced breasts, in that they didnt look quite right and felt strange, but ultimately did the job. And after a number of dives, he thought they were very good indeed.
Another passenger, Margreet Verberg, liked the fins very much from the start, even though they were too big for her.
What we all found was that they were very slippery underfoot, when climbing a ladder or stepping onto the boat's swim platform.
These fins will not be to everyone's taste, but own a pair and your pals will be envious enough simply because of the money you've spent!

Scubapro Twin jet Max £139
Technisub Slingshot £100
Mares Raptor £100

Margreet Verberg with the batwing fins.
Quick - to the Bat Cave!

£350 (Batwings 54 extra)
WEIGHT 2kg per pair
OPTIONS Batwings
DIVER GUIDE width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100%