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Old 18-10-2015, 11:20   #16
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Re: Dolphins smashing into rudder

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Originally Posted by Zaria View Post
We recently purchased an Elan Impression 384 on Lake Macquarie, Australia, and the old owner mentioned to watch out for the dolphins in the lake attacking the boat. We obviously thought he was joking. But sailing today we encountered 2 large dolphins smashing into the Rudder. I was very concerned that they might cause damage, so I rang the old owner who advised to turn on the motor, which did cause them to stop.

But due to dolphins being attracted by sonar, we think the depth sounder, or chart plotter/satellite is what attracted them? Has this happened to anyone else and if so did they stop once the instruments were turned off?
It does sound like odd behavior.

My suggestion is what I would do if in your boat shoes: Post a photo of your rudder and hull design here on this forum as part of the discussion. Then send same with your report to marine biologists at local and other marine labs addressed to scientists who study Dolphins. Odd behavior like this may help them in unforeseen ways.
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Old 18-10-2015, 11:28   #17
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Re: Dolphins smashing into rudder

Sure sounds deliberate (not an accidental collision which would be very unlikely and wouldn't be repeated). Unless this dolphin species is very, very different from others, they don't attack due to any boat instruments.

It honestly sounds like they're playing and have discovered that they can turn the boat by messing with the rudder.
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Old 18-10-2015, 11:50   #18
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Re: Dolphins smashing into rudder

I would think hitting the rudder that hard would possibly hurt the animal. But I guess repeated strikes would prove me wrong.

The dolphins in the Gulf are very good at getting close to boats w/o making contact.

Hope these striking dolphins don't start a new dolphin trend.

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Old 18-10-2015, 11:57   #19
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Re: Dolphins smashing into rudder

Dolphins are one of the smartest creatures on this earth. They were doing it on purpose and was not accidental. Was it being playful, destructive, warnings, bored, or many other guesses....who will ever know?
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Old 18-10-2015, 13:14   #20
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Re: Dolphins smashing into rudder

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Originally Posted by tuffr2 View Post
I would think hitting the rudder that hard would possibly hurt the animal. But I guess repeated strikes would prove me wrong.

The dolphins in the Gulf are very good at getting close to boats w/o making contact.

Hope these striking dolphins don't start a new dolphin trend.

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They have posted it online. But cheer up, only the dolphins with WiFi get it.

I would guess it is a playful gesture on their part and has something to do with your rudder configuration and a particular pod has found it is fun.
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Old 18-10-2015, 13:20   #21
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Re: Dolphins smashing into rudder

Maybe a practice run at something that simulates a sharks fin?

http://news.discovery.com/animals/sh...mes-140814.htm
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Old 18-10-2015, 13:44   #22
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Re: Dolphins smashing into rudder

We've sailed and anchored in Lake Macquarie without any dolphin attention we knew of. Normally, we'd spot them.

Perhaps they learned they could get a reaction from the humans on the boat when they did it? Some of their behaviors seem to be asking for an interactive response.

GILow, please take the issue to your marine biologist mate. I wonder if they are recognizing that particular boat as a plaything? [not all rudders look the same or echosound the same].

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Old 18-10-2015, 13:45   #23
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Re: Dolphins smashing into rudder

It's the dolphins saying "hey man, there is bad weather/pirates/stranded or sinking humanoid/whatever ahead and you should turn this way". That also explains the dolphin exhaling just below the surface to spray you ("Turn that way you dumbass, what do we need to do to get you to turn")
Surely we are of the generation that has seen "Flipper" and can recognize a dolphin trying to save somebody's rear end !
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Old 18-10-2015, 13:55   #24
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Re: Dolphins smashing into rudder

Hi Zaria,

We know those dolphins!! They've followed us on several occasions. We usually pick them up as we go north past Wangi Point and they have stayed with us as far as Rathmines. We've never had any issues with them attacking the boat. Our dog usually alerts us to their presence by pacing forward and aft and looking over the side of the yacht. I think she can hear the dolphins communicating using their "squeals" so she knows they're nearby.

With regard to the depth sounder attracting them I have no idea as we have two depth sounders on continuously and have encountered them under sail only, motor sailing and under power only.

Regards,

Brian
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Old 18-10-2015, 14:12   #25
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Re: Dolphins smashing into rudder

Interesting!
Passed on to acoustic experts.

It would be interesting if the boats that had experienced this compared notes wrt sonar
brands,freq's, type of boat, motive source etc. Response of skipper to "bumping".
see if any correlations.

Learned behaviour, or something else?
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Old 18-10-2015, 14:18   #26
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Re: Dolphins smashing into rudder

An interesting story. Taken at face value, and absent similar reports from other vessels it definitely suggests something about your boat. If it occurs again, you may want to record the obvious circumstances such as time, speed, temperature, visibility, direction of travel, electronics in operation, wind direction, true and apparent, wind speed, surface conditions, location (gps if possible), your boat's bottom color, rudder color, and other vessels in area. Maybe there are common factors to be identified. Listen or ask about reports of similar experiences from other vessels.
That said, I wonder about seeing if anything occurs with changes in speed, direction ans other factors (maybe one by one).
The idea that enters my head is dolphin behavior toward sharks. Head butting them is one that I understand is common. Your rudder could be something they perceive as a threat- visually or maybe by a sound produced by it or something on the vessel, which might explain the behavior.
If this continues to occur you may wish to report it to the marine biology department at a local university. Of course, the clear bureaucratic response would be to ban your vessel from sailing .
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Old 18-10-2015, 15:41   #27
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Re: Dolphins smashing into rudder

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Originally Posted by Pelagic View Post
Maybe a practice run at something that simulates a sharks fin?

Shark vs. Dolphin Battles Can Have Surprising Outcomes : Discovery News
I've heard that also. I doubt that is it. They have a brain larger than ours so with their echo sounding ability that's unlikely.

Why do they ride our bow waves and click at us or even visit with clicks at anchor?

I wonder if anyone has checked if the clicks are binary? We may not be the sharpest knife in the draw?
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Old 18-10-2015, 17:02   #28
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Re: Dolphins smashing into rudder

Antea, my Yankee30 had perhaps a romantic encounter with a dolphin long time ago. My girlfriend and I were motoring through intracostal near Sarasota, she was steering (tiller) I was down below. She asked me to come up, she said something was wrong with the rudder. It was hard to turn at times and sometimes the tiller was moving from sided to side. Antea has a full skeg hung rudder, well swept back, so I had hard time imagining something getting cought on it, but I throttled back and leaned over the transom untill my face was just inches from the water. She was holding my feet so I wouldbn't go over. Which was a good thing, because I got startled and sprung up. A small porpoise tail came up, splashed me and almost hit my face. So now I had to take the tiller, my girlfriend wanted to have a closer look. She reported there was a small porpoise, upside down, plastered against the hull to sarboard of the skeg and rudder, waving it's tail slowly up and down. She could see it's whitish underbelly. Seconds later, it dove, turned right side up and came up for breath along side the cockpit. Then dove straight down under the boat and assumed the same position. How did it keep that up? Did it hook a flipper around the skeg? His nose must have been inches from the spinning Martec folder (at the trailing edge of the fin). Looked like a bottle nose dolphin. She swears it was a boy and had an erection, suprisingly human looking, she said. The guy kept this up for good ten minutes,
untill we passed large ketch going the other way and the guy peeled off and hightailed it after it. Hm, no throughulls that far back. But was he using the motoring sailboat for a vibrator?
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Old 18-10-2015, 17:32   #29
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Re: Dolphins smashing into rudder

And one more contact story. Again, a small bottle nose, a baby this time, 4-5ft long came up on starboard really close by the cockpit all of a suddend. We were sailing along the beach, somewhere on the West coast of Florida. The boat was on autopilot, I was sitting well back in the corner of the cockpit on the low side and reading, so it startled me. We were sailing fast, heeling a bit, so from where I was sitting, I was able to stick my hand in the water and wave it and splash. The porpoise came up again, looked at me and dove, but not before I could brush my hand against it's dorsal fin. After that he came up several more times, one time alowing me to hold on to the fin for few seconds, another time slammed up against me hand hard enough to couse me some pain, but usually just alowing me to pet him once or twice. There may be some laws against doing what I did now, but this was almost 30 years ago, statute of limitations and all that... And yes, I still have the same boat, 35 years later.
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Old 18-10-2015, 17:39   #30
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Re: Dolphins smashing into rudder

I have also come across these dolphins while motoring in Lake Macquarie. They are not your normal fun dolphins, They are larger and have a shorter nose than others I have seen at sea. They also seemed to like being in the propeller wash, and did not play at the front of the yacht like other dolphins. They followed us for a long time, and hit the rudder a few times - the first time hard enough to almost knock the wheel out of my hands. They seemed to loose interest after we stopped motoring.

I have also heard that they have been known to bite rudders, and that they have left teeth marks, but have not experienced this myself.
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