Dolphins smashing into rudder

[Zaria]

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?

[Snowpetrel]

Weird, sailed though countless pods of dolphins and I've never had them so much as touch the boat...

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

[GordMay]

Greetings and welcome aboard the CF, Zaria.

[four winds]

Well, I've never heard of that. Have sailed with dolphins alongside many, many times.

If it were the systems causing it there would be common occurrences of this.

A friend's rudder would "hum" when the boat was making it's best speed. Maybe something like that could cause this.

[GILow]

I am astounded.

I have to ask, and I am sorry if it sounds a silly question, but are you sure it was Dolphins? I mean I am constantly astounded by their ability to avoid collisions with the boat when sailing. I used to panic about hitting them here near home till I saw how fast they move went they want to.

If you are sure they are Dolphins can you tell us which type because I have friends who are marine biologists who may be able to shed some light on the behaviour.


Sent from my iPhone so apologies for weird autocorrect typos.

[barnakiel]

If you have a fine foil rudder (which I think you do) they may be unable to see it from some angles. Esp. if water is a bit murky. They are hitting the rudder because they cannot see it.

b.

[barnakiel]

Your starting the motor may have helped BUT I had also the exactly opposite experience of dolphins visiting as soon as we started motoring - open water dolphins, probably attracted by the sounds we started to make.

b.

[ozsailer]

Hi Zaria,
I live and sail on Lake Macquarie and what you are describing is not the first time the lake dolphins have had a go at yacht rudders. There are a few stories most confirmed of some rudders have been damaged and requiring repair.
I know of one yacht that had its rudder damaged while moored at Wangi Wangi Point. I can also confirm that the dolphins have been known to bump rudders of boats underway. No one I know can offer any ideas with merit on why they are doing it.



Greg and Sue
Sunshine
Lagoon 410S2

[neophytecruiser]

Interesting behavior. Our experience in the Eastern Pacific (California and Mexico) with dolphins, I too, have been surprised how adroit these animals are at avoiding not only the boat, but when over taken by super-pods in the Sea of Cortez, all have managed to avoid the fishing lines being trailed behind the boat. With regard to missing spade rudders due to poor visibility, as far as I'm aware dolphin rely on echo-location (as well as vision) for navigation and feeding.

[Pelagic]

If this is not a Hunter Valley joke......could be the dolphins are trying to get rid of some parasites.

[HappyMdRSailor]

In all the bazzilion encounters we've all had... First time ever I've heard of on purpose contact...

Google gave me this though...

Dolphin jumps into family’s boat, leaves woman with 2 broken ankles | Fox 59

[PuttingDoctor]

Maybe a big eye painted on each side of the rudder might scare them off.

[captain58sailin]

Dolphins see with sonar, that is amazing, I've never had that experience and this is the first time I've heard of it.

[neophytecruiser]

Porpoise/dolphin and echolocation information.
HOW PORPOISES TRACK PREY WITH ECHOLOCATION | Company Of Biologists

[Hydra]

It happened to me in 2004. We were sailing at night from Penmarc'h to Audierne (Ste Evette) and 2 dolphins annoyed us. I suppose there were 2 of them, because we couldn't see them.

One dolphin repeatedly struck the rudder (at least 5 times, maybe 10), so hard that we had to hold the tiller with both hands, else it jumped out of the hand, and the boat tacked! All the blows were from the same side. Obviously, the dolphin was playing at trying to make us tack.

The other dolphin blew to windward of us, but keeping its blowhole just under the surface, so that the spray reached us. It did that a few times, too.

Alain