What is it?

[Jim Walsh]

Here are two photographs I took about 300 miles north of Bermuda. I noticed something on the surface at the furthest extent of my vision. As each swell passed I kept looking in the same direction as I lost sight of it frequently because it was so distant. Over a period of time it appeared to get closer and when still quite distant it was clear it had made a course change toward me. I took several pictures, all but one were of swells, not the subject. The one decent photo is shown below and I cropped the same photo so you can see the fin clearly. It is not a porpoise or whale. It continued toward me until it was a couple boat lengths from my stern. I surmised it was 15 feet long but that is a rough estimate. Apparently it's curiosity was satisfied and it resumed its previous course. It was on a mission.
Anyone familiar with this fin? It is rather distinctive.

[Sea Hunt Video]

Jim:

That is the "sail fin" for the deployable antenna of a Borei-class Russian attack sub. They were obviously pinging and probing your vessel. You are lucky you survived.

It's not enough the Russians are hacking into our emails and election process. Now, they are also going after our pleasure craft.

[jen1722terry]

Could be a sub, but my guess is the giant sunfish, mola mola. We saw one in Cape Cod bay in 2013. I thought it was a whale or shark with the big dorsal fin, so I slowed to idle and let it approach. I've seen a few of these in that area over the years and recognized it. They can get big - a ton or more.

Or maybe it is a sub trying to steal the military secrets of the Cape Dorys. Now you might say that you know of no military secrets on our boats, but if you knew about them, they wouldn't be secrets, would they?

Terry

[bottomscraper]

I'm thinking ocean sunfish also. There is a funny video on Youtube (with some colorful language so I won't post a link) that you can find by Googling "Boston Ocean Sunfish". Melissa and I saw one on our way from P'town to Maine back a few year ago.

[Jim Walsh]

Jim:

That is the "sail fin" for the deployable antenna of a Borei-class Russian attack sub. They were obviously pinging and probing your vessel. You are lucky you survived.

It's not enough the Russians are hacking into our emails and election process. Now, they are also going after our pleasure craft.

I'm glad to see you made it through the hurricane. It appears your sense of humor is intact
Hope the house and boat are intact also.

[Jim Walsh]

It never occurred to me that it could be an ocean sunfish because it maintained course and speed over a long distance and altered course to check me out. I have seen them many times over the years and have seen them move very quickly when they thought I was getting too close but they always appeared and reappeared on the surface. I never saw one "cruising". I presumed it was a species of shark but you may be correct. I thought the fin resembled a mako's dorsal fin but it just didn't come close enough to be sure. It was clearly intent on establishing what I was before resuming its course. That's why I never swim at sea.

[Lisa G.]

The description of its movement does not sound like the sunfishes I have seen. Mako's are very. very fast moving sharks and rarely seen on the surface. It could be another type of shark that do often travel on the surface, like a small blue shark. Marlin are frequent surface feeders too. The fin shape, to me, looks not quite triangular enough to be a sunfish ? and maybe not quite sickle shaped enough for a white marlin? Hmmmmmmm, I think those that said it was a Russian sun might be on to something

[Joe Myerson]

Could it be a basking shark?
One surfaced next to Creme Brulee as I approached the eastern (Sandwich) end, and it was longer than my little boat. I thought it was a whale, my companion insisted that it looked like a shark; I asked a fisherman and he said she was correct. He called it a "whale shark."
Just a guess.
Roberto could be correct, it might have been a Russian sub loaded with hackers.

Joe

[JWSutcliffe]

Looks like the ocean sunfish (Mola Mola) we saw off Block Island a number of years ago. Wild sight, never saw one before.

[Doug Gibson]

We see sunfish on a frequent basis outside the Golden Gate in the Gulf of Farallons. Here's one we saw this August just off Point Reyes. A pretty large one! The real highlight was large numbers of Humpback whales. The last two summers, some have congregated in the Gulf (rather than moving north to Alaska). My estimate was about 50 whales, all feeding on/near the surface. We were surrounded!

[Sea Hunt Video]

While Jim W.'s photos clearly and unquestionably depict the sail fin of a Borei-class Russian sub preparing to deploy one of its antennas, for those of you who still hold to the now debunked thought that the photos depict a sunfish I offer the following brief video:

http://www.cnn.com/videos/travel/2015/1 ... -vstan.cnn

[mgphl52]

Roberto, I can't believe you fell for the lame camouflage the Ruskies use on their subs!

[Steve Laume]

IT is hard to tell from Jim's pictures. The action of a fin is often as important as it's shape in determining who it belongs to. Sunfish fins always look like drunk sharks to me. They kind of wobble around without a predetermined coarse. Shark fins look purposeful and seem to slice through the water with no wobble. There is kinds of stuff out there, Steve.

[Jim Walsh]

IT is hard to tell from Jim's pictures. The action of a fin is often as important as it's shape in determining who it belongs to. Sunfish fins always look like drunk sharks to me. They kind of wobble around without a predetermined coarse. Shark fins look purposeful and seem to slice through the water with no wobble. There is kinds of stuff out there, Steve.

This fin remained as it appears in my photo throughout the encounter.

[Dino]

NOAA has a good guide to identifying sharks by their dorsal fin at http://www.nmfs.noaa.gov/ia/species/sha ... _guide.pdf.

Perhaps a hammerhead or thresher?