2 knot current

[Soggy]

Man, it makes me laugh in people's faces when they tell me how they were diving such and such wreck in a 2 or 3 knot current. 2 knots is ~200 ft/min. Does anyone really think they can swim 200 ft/min on SCUBA? 2 knots is the speed of a Gavin at full tilt. If you've ever been towed by one of those things, you'll know, there is no damn way anyone is going to be swimming that fast. People are so FOS sometimes.

 

[MXGratefulDiver]

I think people mostly just don't know how to estimate those things.

Last week we were kicking into a stiff current ... working to hold position for our safety stop. When we got in, one of my dive buddies asked me how strong the current was. I said maybe a half-knot or so ... she looked really surprised and said "I thought it was 2 or 3 knots".

I don't think people are intentionally exaggerating, I just think it's one of those things that's easy to overestimate until you get some practice at it.

... Bob (Grateful Diver)

 

[jonnythan]

I learned what a 2-3 knot current was a couple of weeks ago when I was diving Lock 23 on the St Lawrence. Cat and I were kicking our butts off (neither of us are exactly slouches), dragging along the rocks in our wetsuits, and still making 0 headway.

3 knots is #!*!@$ fast.

 

[Soggy]

3 knots is #!*!@$ fast.

300 ft/min...swimming the length of the Doria in around 2 mins. Or, the length of the Cornwall in 30 seconds. In a 3 knot current, everyone is going backwards, I don't believe anyone could make headway against that in SCUBA.

 

[FreeFloat]

A quick 'n' dirty way to estimate current (from this reformed dinghy racer) is to check how long in seconds it takes something to float one foot of distance.

Floaty going 1 foot/sec = 1 knot.

We used to do the reverse to judge our boat speed : pick a point and time how long it takes the boat to pass it (you have to know the length overall of your boat)

It's not exact, it's yet another "rule of thumb".

 

[Soggy]

Floaty going 1 foot/sec = 1 knot.

It's not exact, it's yet another "rule of thumb".

That rule of thumb is almost half of reality. 1 knot = 100 ft/min.

 

[MXGratefulDiver]

My rule of thumb ... in 1 knot of current I can hold my own for maybe a couple of minutes. More than that, I'm gonna go with the flow ... :11:

... Bob (Grateful Diver)

 

[Charlie99]

A quick 'n' dirty way to estimate current (from this reformed dinghy racer) is to check how long in seconds it takes something to float one foot of distance.

Floaty going 1 foot/sec = 1 knot.


It's not exact, it's yet another "rule of thumb".

I agree with the method, but use 1/2 meter (or yard) per second = 1 knot.

Another way to estimate is to remember that 10 feet in 6 seconds is 1 kt, which is easy to convert to other distance-time combinations such as 5'/6 secs; 10'/3sec, 5' in 3 sec (1/2kt, 2 kts, and 1 kt).

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Another easy way to make a good estimate of the current is to take the consensus on the dive boat, then divide by half :banana:

Charlie

 

[partridge]

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Another easy way to make a good estimate of the current is to take the consensus on the dive boat, then divide by half :banana:

Charlie

I guess your signature says it all. Maybe even 1/3.

 

[Uncle Pug]

Well sir, we had a fella here on Scuba Board a while back who could dive in a 6 knot current and hold his own... according to him.