I had plenty of confidence in the Italian-made Seac GP100 fins that were sent to me for test. They looked conventional, with their paddle-blades, and they had big comfortable foot-pockets that would suit my big feet.
Not only that, but there was an option to have them supplied with stainless-steel spring-straps (euphemistically called the 4x4 version) and that is what I went for. Call me old-fashioned, but I always use diving fins off-road.
Spring-straps make all the difference to the performance of a pair of fins, because no energy is wasted on wobbling the fins on your foot with every kick.
However, we who have other stainless-steel fin-straps know only too well that the loop of rubber that enables you to pull them on in an instant usually breaks by the 20th or so dive.
Not on these Seac GP100 4x4 fins. The loop arrangement is very substantial indeed. There is no way they will break soon, and the loops for pulling each of them on have a remarkably high profile, yet you can pull them round to the side to make it easier to get hold of them.
The Italians are world leaders in injection-moulding thermoplastics, and these fins are a great example of their work at its best. Three different thermoplastics are employed with GP100s.
They are certainly big fins; about the same size as a pair of Mares Plana Avanti Quattros, but significantly heavier at 3kg for a pair in size L-XL.
They have a three-channel blade measuring 42cm before they integrate in a smooth shape with the foot-pocket.
The foot-pocket itself took my feet snugly and supported them all the way to the heel with an internal measurement of 30cm. The fins became part of my foot and thus an extension of my legs.
Non-slip grips are integrated on the underside so that there are no embarrassing moments on the wet dive platform of a boat. These fins sucked onto my feet so well that I sometimes had considerable difficulty pulling them off after a dive.
I took them on a trip with me to the Brother Islands aboard Grand Sea Serpent in the Red Sea. Some significant currents gave me a chance to see how well I could perform with the GP100s to propel me along.
I reflected that even had I been supplied with the same bike on which Bradley Wiggins flew past my house during the Olympics, I would still take as long as I do now on my old hybrid bike to reach Bushey Park. That’s because I’m getting older and more knackered.
It was the same with the Seac GP100 fins.
I continually had the feeling that on the right pair of legs they would be magnificent performers. On mine, at times I felt I was swimming in treacle.
There was certainly no tendency to slide sideways on the downward kick, thanks to the strong side-rails on the blades, and I did feel that all my strength was being transferred to shifting water. I could have done with a little more strength, that’s all!
So if you’re looking for a pair of fins and you don’t have legs like Usain Bolt’s, you might find GP100s less than satisfactory. Every day in the water, they reminded me that I should give up swimming and use a DPV.
On the other hand, you might find that the rigidity of the blades combined with the fit of the foot-pocket and the robustness of the spring-straps make these the best fins you’ve ever tried. As I said, choosing fins is a very personal affair.
Seac GP100 4x4s are seriously tough fins for seriously tough divers. They might look expensive but they look as if they will last forever.

Comparable fins to consider (without spring-straps):
Mares Plana Avanti Quattro, £85
Aqua-Lung Slingshot, £90
Aeris Velocity X3, £90

PRICE £89 (4x4), £79 with conventional rubber straps
COLOURS White, red, blue, yellow, black
CONTACT www.blandfordsubaqua.co.uk
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