I agree most folks over estimate current speed. The time I lost my suit, it might have been getting close to 5 knots. Most divers complain the current is too strong when it's getting up to ½ knot.
Where have you experienced the strongest currents?
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UCFKnightDiver
Contributor
Weeki Wachee Springs, Have also bad currents out of West Palm Beach 2-3 knots as well as diving on the Speigel Grove where I would estimate the current at maybe 2-3 knots as well.
Oh and in excess of 4-5 knots I seriously doubt you were diving there and if you were, you were in a world of trouble as just 2-3 knots is extremely hard to swim against.
Oh and in excess of 4-5 knots I seriously doubt you were diving there and if you were, you were in a world of trouble as just 2-3 knots is extremely hard to swim against.
It has been described as "like a dozen fire hydrants". Blue Springs in Orange City, FL flows 110 million gallons of water daily, from a hole the size if a matress. You can get a close look, but a diver close to and directly in the flow will be moved severely upwards and backwards.
Just to the knees.
fairybasslet
Contributor
Galapagos. Almost ripped my reg right out of my mouth.
Ana
.
From OSHA, it may be old but the updated rule is probably very close to this:
<<29 CFR 1910.424(b)(3). Each SCUBA diver must be line-tended when the current exceeds one knot. Three basic types of currents affect diving operations: river or major ocean currents; currents produced by the ebb and flow of the tides (which may add or subtract from any existing current); and underwater or rip currents caused by the rush of water returning from waves breaking along a shoreline. The CSHO shall determine that the employer has ascertained the strength of the local currents at the dive site from Tide and Current Tables, Coast and Geodetic Survey Charts, Coast Pilot Publications, or other sources. A SCUBA diver is seriously encumbered when swimming against a current exceeding one knot, and the standard prohibits such activity unless the diver is line-tended. A SCUBA diver may, however, swim downstream with a current when means are provided to pick the diver up (such as retrieval with a boat).>>
I followed the above rule from OSHA when working on bridges, 2 knots was the cutoff, after that work stopped. My employer at the time was very resourceful finding data that fit his needs and grossly underestimated current strength.
I now have access to equipment designed to measure current and realize how wrong I was each and every time that I figure 2 or even 3 knots current, based on speed from the boat gps while drifting and other methods that didn't involve a CTD device or similar.
It doesn't take a lot, to blow your mask off the face if you let the water hit it just right (or in this case, just wrong).
Human senses don't have what it takes to gauge the strength of water hitting the body, different parts of the body produce different conclusions. With practice we can estimate horizontal distances, weights of objects and a few other things fairly close, but try vertical distances... a lot harder without very exact references.
Estimating water speed is similar to wind speed, humans can only "feel" that they are strong, but not even the Weather channel guy can estimate a 60mph wind today and a 30 tomorrow and a 100 the next day.
You may swear that you dove on 7 foot seas and a 4knot current. But calibrated instruments don't lie.
It is weird to experience a 2 foot sea on a 100' vessel and then when it almost looks like is less than 2' transfer to a 12' RHIB. Suddenly that flat sea becomes not so flat anymore, you look at the wave-buoy data and sure enough still 2' or even less.
<<29 CFR 1910.424(b)(3). Each SCUBA diver must be line-tended when the current exceeds one knot. Three basic types of currents affect diving operations: river or major ocean currents; currents produced by the ebb and flow of the tides (which may add or subtract from any existing current); and underwater or rip currents caused by the rush of water returning from waves breaking along a shoreline. The CSHO shall determine that the employer has ascertained the strength of the local currents at the dive site from Tide and Current Tables, Coast and Geodetic Survey Charts, Coast Pilot Publications, or other sources. A SCUBA diver is seriously encumbered when swimming against a current exceeding one knot, and the standard prohibits such activity unless the diver is line-tended. A SCUBA diver may, however, swim downstream with a current when means are provided to pick the diver up (such as retrieval with a boat).>>
I followed the above rule from OSHA when working on bridges, 2 knots was the cutoff, after that work stopped. My employer at the time was very resourceful finding data that fit his needs and grossly underestimated current strength.
I now have access to equipment designed to measure current and realize how wrong I was each and every time that I figure 2 or even 3 knots current, based on speed from the boat gps while drifting and other methods that didn't involve a CTD device or similar.
It doesn't take a lot, to blow your mask off the face if you let the water hit it just right (or in this case, just wrong).
Human senses don't have what it takes to gauge the strength of water hitting the body, different parts of the body produce different conclusions. With practice we can estimate horizontal distances, weights of objects and a few other things fairly close, but try vertical distances... a lot harder without very exact references.
Estimating water speed is similar to wind speed, humans can only "feel" that they are strong, but not even the Weather channel guy can estimate a 60mph wind today and a 30 tomorrow and a 100 the next day.
You may swear that you dove on 7 foot seas and a 4knot current. But calibrated instruments don't lie.
It is weird to experience a 2 foot sea on a 100' vessel and then when it almost looks like is less than 2' transfer to a 12' RHIB. Suddenly that flat sea becomes not so flat anymore, you look at the wave-buoy data and sure enough still 2' or even less.
Cooper River, Charleston SC. Missed timing the tide and had a very interesting time. I had to dial my reg all the way down and hammered a spike into the bottom with a clip attached to me to stay in one place. Even then, if I did not bury it at least a foot into the bottom it would pull loose.
bobcatdiver
Registered
I would have to say the St. Lawrence river around Brockville ON. Great diving and super wrecks but you better hold on.
Cairns, Australia.
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