The Offshore Voyaging Reference Site

Watch Out For Whales, Part I

Another race, another whale collision, yet again ending in the loss of a boat and injury to a whale. Thankfully no loss of life, although one day that may not be the case. What is happening out on the oceans? Pirates everywhere, climate change driven hurricanes, and now homicidal whales?

Well, the first and most obvious cause is that there are far more of us out there, so the odds of collision have gone up. Whales seasonally inhabit many sea areas that are also cruising waters for yachts, such as Tonga, Hawaii, New England and the Azores. And as more yachts start cruising in higher latitudes where whales have always been more numerous, the odds of a close encounter increase again.

Equally, some species of whales are estimated to have increased their numbers dramatically after the cessation of hunting. According to International Whaling Commission statistics, humpbacks have increased by 13.9% in some Australian waters. In the North Atlantic, minke whales have increased by over 8%, possibly through taking advantage of the ecological niche vacated by the great whales after centuries of overexploitation.

Whales obviously don’t spend all of their time in the depths feeding, being mammals they have to spend at least part of their time at the surface, breathing. But they also sleep at or near the surface for part of their day, usually at night when they are least likely to be spotted. And although they ‘sleep with one eye open’, there is some evidence that many whales have suffered hearing damage due to exposure to the extraordinarily loud noises in the oceans caused by military sonar and seismic activities. And there is so much more background noise in the oceans today—an estimated increase in background sound of 15db over the last fifty years—that only really loud sounds might now be heard by a snoozing whale, and the quiet approach of a sailing vessel may simply be undetected.

Working in marine life research has meant a lot of time spent in company with whales, dolphins and sharks, and for 99% of the time it has been nothing but wonderful, although we’ve always been very careful to remember that we’re around wild animals. Do whales approach boats? Yes, certainly, sometimes for hours; one minke whale repeatedly dived underneath, rolling upside down, examining our beautiful Frers-designed underbody in a manner that might easily have been construed as amorous. Thankfully, whales have excellent spatial sense, and it never touched us. Can whales be aggressive? Well we’ve been buzzed at close range by a bull pilot whale when a tiny calf approached us, so I wouldn’t doubt it. And there have been well documented reports of whales damaging boats, usually after a collision with a member of a pod.

And collisions can occur all too easily: In bad weather or an ocean swell it is far from easy to see a whale until it’s very close indeed. Heading out into a big Celtic Sea swell in the first light of dawn, we were suddenly shocked out of our torpor by a volcanic eruption of fetid air and water less than 10 feet away, followed by a shiny black freight train going in the opposite direction—our first fin whale. And basking sharks, which can hardly be described as intellectual giants, generally won’t even try to get out of your way, so fixated are they on scooping up plankton.

Is there anything we, as sailors, can do to minimise the risks? Well, most whale grounds and seasons are fairly well known, so advance research when planning a passage may help. If a passage involves crossing a continental shelf break (where whales and other sea life gather), doing so in daylight might help. Groups of whales might best be avoided, especially as calves are likely to be present and any perceived threat to them might easily be construed as aggression and be met with the same in return. Most experts agree that the best course of action is to slow down and make a gentle course alteration away from the animals. Running the engine may warn the whales of your presence, which might help. And if your yacht is approached, try to maintain your course and speed to minimise the risk of a collision. And cross your fingers!

There may even be a technical fix coming at some stage. Dr. Michel André has developed an electronic approach called the Whale Anti Collision System, that employs an array of hydrophones to listen for whale echolocation clicks to establish the presence of whales in an area. They believe that at some stage in the future they will be able to provide advance warning of the presence of whales to yacht races passing through such areas, and so, hopefully, reduce the risks to both whales, yachts and their crews. Perhaps such information might even be available to cruising yachts one day.

In every area of the oceans there are research groups such as the Sea Watch Foundation (UK) in the NE Atlantic who actively solicit whale sightings from yachts that venture offshore. Not only is this a valuable resource from a research point of view, but the patterns of distribution that emerge may be useful to all of us cruisers in the future when planning routes across the oceans.

French skippers over here look at our white antifouling and laugh, saying that big whales just love white underbodies; who knows? Lou says that the white has got to go, and we’ll go for ‘stealth’ black. Oh well, better safe than sorry!

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frank reveil

We sail in the pacific where whales are every where and unavoidable. we encountered Sperm, Sei, humpbacks, Minke, and Pilot whales in middle ocean. Do you imply that we should only go to Alaska in the winter and the tropical waters during the hurricane seasons when they are less present? both humans and whales like the same waters and we have to share .
From our steel hull we can often ear theme but we can’t tell their where about. Being noisy, so they can hear you coming is a good idea. we are sailing much slower than they can swim unlike ocean-liners and most cargo-ships . Collisions between sail boats and whales are very rare never the less we like the safety of our steel-hull.


Black or blue antifoul might not be the best choices either …… could be confused with a competitive whale …. or other threat. It might be worth some research on past collisions to find out the colour of antifouling.

Marc Dacey

An interesting point and one certainly backed by the stories of wetsuit-clad surfers getting chomped by sharks because they resemble seals when paddling…at least from below and to the shark’s allegedly small and one-track mind.

I heard some scuttlebutt a while back that wetsuit manufacturers were devising lime-green, pink and bright yellow wetsuits on this basis. Colours not found in nature might lessen the resemblance to food, I guess is the premise.

The same might be said for hulls and whales. I know the only time I’ve seen one (as opposed to not seeing one that might have been close) while offshore, it looked young and…slightly miffed? Hard to say! But it veered away from the stern with a sort of “sorry, my mistake” look on him. Maybe I’m projecting, but it’s not beyond reason that a reasonably intelligent mammal can appear slightly baffled. Dogs, cats and pigs do it all the time.

Colin Speedie

Hi David & Marc

The subject is complicated by the fact that whales are (to an extent) colour blind!

Over the years I’ve spent a considerable amount of time close to whales working on research projects, and I’ve never been convinced one way or another that one colour of antifouling has made any difference to behaviour, while we were convinced that white was the best colour around basking sharks – they tended to alter course away from us earlier than with other, darker colours.

What is/was true with whales, as far I could see, was that whales had ‘personalities’, some being far more boat friendly than others. And, as you might expect, juveniles tended to be far more inquisitive than adults – just like humans, in fact.

Best wishes