long island sound

[dave]

i was sailing the sound this weekend and noticed something weird. I'm new to sailing so this might not to weird to the rest of you. Out of the marina the water was real calm. But once I got out about a mile or two, the water was extremly rough. It wasn't gradually getting rough but there was a distinct line on the water where it was much darker and the waves much bigger. As far as I could see the water past this break was darker and the waves were much bigger. What causes this and is it alright to sail into this? Thanks, dave.

 

[Will]

Rough waters

I don't have my charts with me as I write this, but there is an area about where you describe that has rocky ground and is usually rougher than the surrounding waters. The fish apparently love it, and you will often see powerboats fishing there. I rafted up with a powerboat friend there once and started getting seasick after about half an hour of the wave motion. I don't know how they can stay there long. I sailed around Faulkner Island on Saturday, and noticed a similar area eadt of the island.

 

[Tom]

You'll get used to seeing it, its the tide

But its good that you noticed it, it shows that you are paying attention to the environment around you.I don't know specifically where you are referring to, but I can hazard a guess to the cause of the "extra disturbance" in the water around you. It is caused by the tide "rolling" over a change in the sea bottom below the "rippling" of the water. Typically you will see it running *mostly* north and south in the Long Island sound, due to the tidal current being mostly east and west.I was just out your way 2 weeks ago and there was a very distinct disturbance in the water ahead. When I looked at the charts I noticed it corresponded very closely with the bottom depth changing abruptly from over 100 feet deep to about 30 feet deep. So when the tidal current (which can be over 1 knot in Long Island Sound) gets going its like mini-rapids occuring on the sound. You really see the effects of this in the area called the "Race" one minute its perfectly calm the next you are in steep 10 foot waves.Just beware....this rippling can also meen that the water is getting *very* shallow and that there might be an underwater reef/sand bar to be carefull of.So go back to your charts and the approximate place where you saw the change in the water and let us know if there is a significant change in water depth and also is this a place with a tidal current running across it. (remember if its slack tide -- you wont see it)

 

[Garry@S/V TASHTEGO]

Dead Water

Many years ago, in 1972 or 73 there was a hurricane which caused a minor flood in the Connecticut River on the fifth of July. I took a 21 foot Aquasport over to Saybrook to sample the flood waters and as I went in toward the mouth of the river I came on a very distinct line in the water and, once inside the line, found the big Johnson outboard had lost its grip and the boat would hardly move. This was the phenomenon of "dead water" which larger vessels sometimes encounter entering harbors. The cause was the fresh river water floating on the denser and saltier water from the sound. The line was decorated with twigs and other junk and showed that the river water was flowing out over the saltier water carrying the twigs and leaves and the "rolling over" itself like thin pancake batter spreading on a griddle. There were no waves on the surface of the river water at all. It turns out that the density contrast promotes the formation of internal waves on the salt-fresh interface which eat up energy put into the fresh layer. The prop was right on this interface when I entered and was flailing away making these internal waves. Once up in the river the boat ran fine again. I bet this was what you experienced. Had it been raining hard recently? Was the boat harder to drive in the calm water near the line?