Orca attack

[Trident]

Well sadly I've just ordered 4 cans of black hard antifoul to put on before crossing Biscay this summer - as a cat I really should take the chance to get a pot of white too and do one hull in each colour . I can then count bite marks on each hull

Hopefully the fact that my rudders are solid stainless steel and skeg mounted with a bottom pintle will make them not want to taste it more than once - though in truth I imagine 1/4 inch 316 stainless plate would be like tissue paper to an orca

 

[Adios]

Oh dear!

In the good old days of Practical Boat Owner someone would have written an article describing how to make your own depth charges.

Hot wax dip some firecrackers that you've threaded with a thin strand of copper to act as a burning fuse, attached to heavier 12v wire attached to battery through a switch panel. Have some ready to deploy over the transom.

This is a cheap way to use a legit method used in whale preservation after oil spills How Do You Keep Killer Whales Away From an Oil Spill? | response.restoration.noaa.gov

 

[JaninaofDorset]

Seems that over half the boats attacked so far had black anti fouling according to the Cruising Association:
.
Black antifoul suspected cause of orca attacks

only if it was 100% of black boats

 

[jimi]

Could an orca expert not produce a sound pattern that says “ Go away, you are being silly and endangering lives!” They seem to think orcas are intelligent and can communicate freely

 

[FinesseChris]

Oh dear!

In the good old days of Practical Boat Owner someone would have written an article describing how to make your own depth charges.

The same writer who outlined the hand held rocket launcher system for deterring jet skis, I expect

 

[GHA]

Could an orca expert not produce a sound pattern that says “ Go away, you are being silly and endangering lives!” They seem to think orcas are intelligent and can communicate freely

Different pods speak different dialects & can´t speak to each other.

 

[Daydream believer]

A friend of mine entered for this years ARC is concerned about the trip south. On reading about colours of antifoul paint he said that he intends to paint his rudder 7 keel white but leave the hull of his 41 ft Jeneau black as usual.
I have pointed out to him that black & white might look like an orca from a competing pod & attract some hostility. He is now having second thoughts. So the idea of a catamaran painted in 2 colours, as suggested earlier in this thread, may not be so clever.
Does red signify blood?

As for the suggestion of explosives, I wonder if an orange marker flare dropped on the surface of the water might be better. It does not cause any noise & disperses fairly soon. But the orange spread on the surface might confuse the Orca as it surfaces through it to breath. Sand has already been suggested as a deterent due to its effect on their breathing, so this could be a less harmful method than blowing their brains out. That being said, some might just like to try the latter.

 

[Daydream believer]

Different pods speak different dialects & can´t speak to each other.

So they demonstrate some human traits then

 

[Pete7]

When you look at yachts from underneath - they all seem black, they are in the shade, and as most AF tends to be dark........

Red light is one of the first colours to be absorbed as you go under water, which is why blood appears black under water.

Pete

 

[jimi]

Different pods speak different dialects & can´t speak to each other.

Surely there must be some common sounds to communicate a warning?

 

[GHA]

Surely there must be some common sounds to communicate a warning?

Why would they have a word for warning? They are top of the chain and nothing to be scared of with no enemies .... apart from some big brained monkeys with guns and money now.....

 

[jimi]

Why would they have a word for warning? They are top of the chain and nothing to be scared of with no enemies .... apart from some big brained monkeys with guns and money now.....

apparently Pilot whales chase them. So maybe a Pilot whale shouting "Eff off" or similar might be worth trying

 

[GHA]

apparently Pilot whales chase them. So maybe a Pilot whale shouting "Eff off" or similar might be worth trying

You reckon???

Apparently Pilot whales have been recorded pretending to be Orcas so they don´t get eaten.

Pilot Whales Show Possible Orca-Mimicking Repertoire.

Evidence from orca stomachs shows they do occasionally eat pilot whales. But pilot whales can mob and chase orcas away, the only cetaceans seen defending themselves from the apex predator in this way.
Mimicry could serve as an additional defense: “One hypothesis is that if they use similar sounds, they may not be recognized as prey,”

 

[jimi]

You reckon???

Apparently Pilot whales have been recorded pretending to be Orcas so they don´t get eaten.

Pilot Whales Show Possible Orca-Mimicking Repertoire.

Evidence from orca stomachs shows they do occasionally eat pilot whales. But pilot whales can mob and chase orcas away, the only cetaceans seen defending themselves from the apex predator in this way.
Mimicry could serve as an additional defense: “One hypothesis is that if they use similar sounds, they may not be recognized as prey,”

worth a read.
Iceland’s Orcas Will Do Anything to Avoid a Pilot Whale

 

[Hydrozoan]

Orca mothers make 'lifelong sacrifice' for sons - BBC News

The full paper is here and explains a lot more about Orca reproduction, and the consistency of that 'lifelong sacrifice' finding with bisexual philopatry (both sexes remaining in their birth areas) and outgroup mating. Costly lifetime maternal investment in killer whales: Current Biology (cell.com)

 

[Beneteau381]

We have red AF (on a cat) because it is most easily spotted by air, from a helicopter. Black, white, blue, green etc tend to merge into the sea scape. And white is a misnomer

If I had to guess I might have guessed that a dark blue was the most common colour used in AF but I think in addition to suggesting that black is the most common colour suffering attacks they need to define what colours were used and how many of each colour. There is no evidence that colour impacts AF performance - so choice should be on the basis of aesthetics, or maybe (as in our case) safety.

When you look at yachts from underneath - they all seem black, they are in the shade, and as most AF tends to be dark........

The idea that Orcas are very intelligent but choose yachts with black AF preferentially - seems contradictory. It suggests that not only are they very intelligent but that they can differentiate between the shaded colours of dark blue, black, dark green. Additionally if the Orcas have this behaviour because they find it entertaining it is difficult to imagine that a dark colour, sorry, black is more entertaining than a lighter colour, say dark blue.

Makes no sense to me.

However if you dither over the choice of colour for AF and you really do not mind - then why not choose a colour as far from black in the spectrum - somethings pale (or red) at least you know when you need to scrub the hull. Or if you lose your keel and you use red AF- you might be spotted earlier.

It will be interesting to read how this all develops. The AF companies will be watching this with interest.

Jonathan

The CA is helping collating evidence and have come out with preliminary thoughts on the results so far. Your thoughts on what is going on in a place halfway across the world from you and comments like "makes no sense to me" are not very clever. The CA comments are based on preliminary evidence not a WAG. For info, antifoul available easily, in and around the Algarve is primarily reddish or black. So most boats have a red or black bottom. In the UK a shade of blue seems to be the preferred colour.
Different folks different strokes.

 

[Beneteau381]

Oh dear!

In the good old days of Practical Boat Owner someone would have written an article describing how to make your own depth charges.

Why when people can buy "big" bangers in Spain?

 

[Neeves]

The CA is helping collating evidence and have come out with preliminary thoughts on the results so far. Your thoughts on what is going on in a place halfway across the world from you and comments like "makes no sense to me" are not very clever. The CA comments are based on preliminary evidence not a WAG.

Its a forum, most people here are expressing thoughts. The CA have come up with preliminary thoughts, If you can quote second hand preliminary thoughts then I am fully entitled to add my own thoughts. Members can decide if they agree with me, or not. We don't need anyone picking on one person repeatedly - it becomes obvious you are biased and is, at best, unhealthy, and as far as I am concerned - unnecessary

I think you like being picky and are inconsistent with your pickiness - and I wonder why.

Go get a life.

Jonathan

 

[sailaboutvic]

One has to be careful what said when it comes to the CA , members will come out guns shooting .
But the fact is all that's happen is they put any data they got into a computer and crunch the numbers and came up with black AF
I know three CA boats returning from the Med last year one had some damage one had an interaction no damage and the other had no problem , non reported their trip to the CA .
And funny enough the one that had no problem had black AF , that throw a spanner into the works .
We back to three years ago , we know nothing new , well other then going into astern before any damage may send them packing .

One has to wonder what tho who are defending the CA data would say if it was the green party who came up with the suggestion.

 

[Adios]

Red light is one of the first colours to be absorbed as you go under water, which is why blood appears black under water.

Pete

If your boat is deep enough for that to be a factor...