RK3 HDs and diving.

[BoatingDave]

I would be interested to hear if anyone can speak to the stiffness of the RK3 HD fins compared to some of the other stiffer fins out there like the Jets, Eddies, XTs, Slipstreams etc.

So I ended up getting the rk3 HDs. I'm diving with them this weekend. I'll post back about floppiness/bouyancy and power.

 

[BoatingDave]

Ok the follow up. Completed 4 dives in key largo, mostly shallow reef diving. Moderate surge on all of them, two dives with moderate current. The rk3 HDs were great fins, definitely a little negative, but not ridiculously so. However, I always wear 6.5 mm booties so not sure if that cancels out the negative buoyancy. I loved the fins for frog kick, they seem tailor made for it. less power than I expected with flutter kick, maybe because they are shorter fins, but still very good power. Moderately stiff fins, but not as stiff as you’d expect. Overall excellent fins. Very happy with the purchase. Not overkill for warm wetsuit diving, probably perfect for diving dry or for more technical precise finning diving.

 

[RobPNW]

Ok the follow up. Completed 4 dives in key largo, mostly shallow reef diving. Moderate surge on all of them, two dives with moderate current. The rk3 HDs were great fins, definitely a little negative, but not ridiculously so. However, I always wear 6.5 mm booties so not sure if that cancels out the negative buoyancy. I loved the fins for frog kick, they seem tailor made for it. less power than I expected with flutter kick, maybe because they are shorter fins, but still very good power. Moderately stiff fins, but not as stiff as you’d expect. Overall excellent fins. Very happy with the purchase. Not overkill for warm wetsuit diving, probably perfect for diving dry or for more technical precise finning diving.

Thanks Dave, that was helpful. What size boots and fins did you get in the 6.5mm? I have the ScubaPro HD full sole boots in size US 9 and was thinking the large fins would be a good size and still be big enough for Rock boots dry diving.

 

[BoatingDave]

Thanks Dave, that was helpful. What size boots and fins did you get in the 6.5mm? I have the ScubaPro HD full sole boots in size US 9 and was thinking the large fins would be a good size and still be big enough for Rock boots dry diving.

I got the “large” size using a US size 9, 6.5 mm boot. Fits me perfectly, and the stainless steel heel spring makes donning and doffing so much easier than my old fins. Medium was definitely too tight (toe squeeze) and the super size was too big. My LDS suggested that you might need to go up a size if you used rock boots but i did not try them with rock boots. I’d say I still have room in the fin if I were to wear a thicker boot/shoe and they might work for you given the spring strap would be able to stretch more.

 

[Pearlman]

Today I got a change to try-on the RK3 in a local dive shop using a 2mm bootie. Perplexingly - The medium which had the perfectly sized surrounding foot pocket and weight (and acceptable strain on my leg muscle with a lifted leg crossed at 90deg in seated position) had my toes pushing into the foot pocket to the point of folding and curling them over. The large was too heavy and gave an uncomfortable strain and weight on my lifted leg with the spring strap leaving a 3-5mm gap behind my heel! I wear a US size 10. There was no way to adjust the spring strap on the medium size to not push my toes into a crunching fold. The large was clearly too loose to consider.

What’s with this weird fit?

 

[BoatingDave]

Today I got a change to try-on the RK3 in a local dive shop using a 2mm bootie. Perplexingly - The medium which had the perfectly sized surrounding foot pocket and weight (and acceptable strain on my leg muscle with a lifted leg crossed at 90deg in seated position) had my toes pushing into the foot pocket to the point of folding and curling them over. The large was too heavy and gave an uncomfortable strain and weight on my lifted leg with the spring strap leaving a 3-5mm gap behind my heel! I wear a US size 10. There was no way to adjust the spring strap on the medium size to not push my toes into a crunching fold. The large was clearly too loose to consider.

What’s with this weird fit?

Hmmm, not sure. That’s odd. My 6.5 mm boots (size 9 shoe) fit the large perfectly so maybe your 2 mm bootie is much thinner/different shape in the heel?

 

[Pearlman]

Hmmm, not sure. That’s odd. My 6.5 mm boots (size 9 shoe) fit the large perfectly so maybe your 2 mm bootie is much thinner/different shape in the heel?

So sturdy boots are a must? I was hoping I could substitute a 2mm bootie with a neoprene sock when shore/boat diving for whatever fins I buy…

 

[BoatingDave]

So sturdy boots are a must? I was hoping I could substitute a 2mm bootie with a neoprene sock when shore/boat diving for whatever fins IMaybe you’d be able to find a happy medium a

So sturdy boots are a must? I was hoping I could substitute a 2mm bootie with a neoprene sock when shore/boat diving for whatever fins I buy…

Sounds like you may need something a little thicker if you want to go to the large.

 

[buddhasummer]

Not a fan, in my size the blade is tiny, very comfortable and I'm sure in a tight environment they'd be great but I couldn't generate enough power in a current. FWIW My go to wetsuit fin is the DR XT.

 

[CaptainChris]

I swapped out Scubapro jet fins for RK3 HD as I found the jet fins too heavy and struggled (though I do have a knee replacement) Find the RK HD excellent and I use them for deep diving either in my drysuit or in my 5mm wetsuit and 5mm boots. I use trim weights on my wing and adjust as necessary.
I find them easy to get on and off and not tiring on the old legs and knees!