scary surge/tide experience - Rockport, MA

[sunapeebob]

I tell friends interested in diving, that the negative experiences teach you more than just positives and it takes a long time to become proficient in diving. This is one of those. My son and I were diving at Back Beach in Rockport, MA Saturday morning. This is a common training area. This was our first ocean dive of the year ( had had dives in fresh water this year). It was primarily a shake down dive. My son has about 250 dives and is rescue certified and I have about 100 dives and am AOW. We were diving dry. We entered the water at high tide. In fact, I had not seen it that high at Back Beach before. My son tells me afterward that he thought it was near full moon recently. We went in and the vis was <5 feet. We went out a ways, hoping the water would clear some - no dice. We went about 150 yards off shore. We decided to call the dive. We started back in and that is when we noticed that there was a large surge and the tide was really ripping going out. We had a very hard time coming back in. We tried to go to the bottom and hug this, but it was even worse vis now and we couldn't keep an even compass heading due to the receding tide and surge. We decided to surface swim it in. However, we were not really making headway. I decided to come closer to the breakwater, thinking that would get me out of the receding tide - then got thrown onto the rocks. I caught my breath and then resumed swimming in. We finally made it past the breakwater and into a private little harbor area for some sort of condo. My son essentially pulled me into this area. Kudos to my dive buddy! We unrigged and talked about what had happened. We clearly had misread the tide. I do not know if the moon had any effect on this tide. There was a small onshore breeze, but it did not seem much. I was a little overweighted, which might have contributed to the increased workload.

I do find that my own negative experiences teach me to be safer, but I am not sure what I would have changed, other than calling the dive sooner, staying away from the rocks towards the center of the beach area, better weighting (new tank - was not sure of the -lbs), etc.

I have read other threads about surges elsewhere, this is the most I have experienced to date as well as the tide going out. It was not a rip current, but acted a little like one. From the time we entered to the time we left, about 1.5 hours, it had dropped somewhere between 4-6 feet.

Thoughts, suggestions, etc would be appreciated.

Bob

 

[iztok]

I do not know if the moon had any effect on this tide.

You should be pretty sure that Moon had just about everything to do with this tide as it does with any other tide it is exactly why tide is happening (Sun does to extent as well.)

 

[divin'dog]

Glad it all came out ok. I wouldn't have thought that the Back Beach would have such a strong current but live and learn. There are some of my favorite dive spots where I know enough to take the tides into consideration. Dive slack tide when in doubt.

 

[TSandM]

We deal with tides and currents all the time in Puget Sound, and one thing you learn is that, for any site you want to dive, you need to learn the idiosyncrasies of that place with respect to the tides. There are sites you can dive on any flood, but not on any ebb; there are places you can dive on any tide 90% of the time, but every once in a while, you'll get caught in an aberrant current that can end up landing you hundreds of yards from the normal exit.

I guess my question is, how much did you know about this site? Is this one you have many dives at, which behaved in an unusual fashion? Or is this a site you don't know well, where having talked to people who dove it frequently might have keyed you in to tidal conditions where it is not good to dive there?

Once you are in the water at the wrong time, all you can do is cope. Getting down on the bottom and crawling, using knife or light to grip the sediments, can be a strategy. This is where wrist gauges are priceless, because you can watch your depth and your heading while you are pulling. Surge marks on the bottom or depth contours are useful, too; sometimes you abandon the hope of returning to your precise exit, and are just happy to get to shore anywhere.

Glad you're okay. These problems are best solved by planning, but if you have to cope, you at least stayed calm and had enough gas to get out.

 

[sunapeebob]

Thanks for the responses. It is an area I have dived numerous times. I did part of my AOW training there. It is very common for classes to take place there. I do admit that I had never seen the water that high before. I know that the moon and sun are responsible for the tides, but I believe that it was just about fullmoon and this in combination with perhaps an onshore breeze drove the larger tides. I am glad to learn. It has made me much more conscious of observing the big picture, even in areas I think I know. In a less known area, the radar would be up a bit more. Live and learn.
Bob

 

[iztok]

I believe that it was just about fullmoon

Full moon doesn't matter. Gravitational force of the moon doesn't change if the moon is full or not

 

[bleeb]

Full moon doesn't matter. Gravitational force of the moon doesn't change if the moon is full or not

Not sure you mean that the way it reads literally. As you said, the gravitational force of the moon doesn't change, but as the OP implied, a full (or worse, new) moon does indeed affect the size of the tides, since the Moon and Sun are aligned at those times, and the tidal effects of the two are combined.

 

[Hank49]

Full moon doesn't matter. Gravitational force of the moon doesn't change if the moon is full or not

I remember reading about tides off North Carolina after someone asked about tides and currents there. I seem to remember looking at tide charts for there and some areas weren't that affected by the moon phase as far as extreme highs and lows.
But every place I've been has more tide, higher highs, and lower lows, during full and new moons.

 

[openmindOW]

Thank you for your post, Bob. In posting here, you are helping other divers to learn. Thanks.

Sometimes, the enormous power of a tide or current is something that you just have to experience in order to fully appreciate.

It has happened to me surfing - twice. Each time, I was happy to be in a wetsuit because I knew I was positively buoyant.

Keeping, diving.

 

[dumpsterDiver]

Tidal currents can really screw you up. I had a learning experience in the Orcas Islands on a solo dive i did from shore, wiith zero clue about tides. Also had a memorable experience in the Bay of Fundy.

Local knowlege is very important, but it sounds like the OP had that. Going to the surface to swim in was the WRONG thing to do if you could navigate underwater. It is much better to carry an extra 8 lbs of extra lead and hug the bottom and crawl in on the bottom, compared to trying to swim on the surface against a current.

Cold water (heavy suits) and big currents always scared me, because if you screw up bad and get offshore, you might die of hypo-thermia before anyone knows you are missing. Sometimes there is no substitute for physical fitness and being able to muscle your way out of a bad situation.