"Porpoise-friendly" echo-sounder design project, University of Southmapton

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SouthamptonStudent

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I am student at the University of Southamptom, United-Kingdom, attending my fourth and final year of Acoustical Engineering. Me and two other students are currently working on a project aiming to design a "porpoise-friendly" echo-sounder for pleasure craft embarcations. In order to design a product that will also meet the demands of the customer, we want to understand those demands and know more about the use boat-owners make of their echo-sounders.

We would therefore appreciate if you could answer these few questions to help us with our project (if you have an echo-sounder).

1. What type/model of boat do you own?

2. How often do you use your boat?

3. What model is your echo-sounder?

4. When out to sea, do you have your echo-sounder on continuously?

5. If not, in what circumstances do you turn it on?

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?

Thanks in advance.
 
SouthamptonStudent said:
I am student at the University of Southamptom, United-Kingdom, attending my fourth and final year of Acoustical Engineering. Me and two other students are currently working on a project aiming to design a "porpoise-friendly" echo-sounder for pleasure craft embarcations. In order to design a product that will also meet the demands of the customer, we want to understand those demands and know more about the use boat-owners make of their echo-sounders.

We would therefore appreciate if you could answer these few questions to help us with our project (if you have an echo-sounder).

1. What type/model of boat do you own?

2. How often do you use your boat?

3. What model is your echo-sounder?

4. When out to sea, do you have your echo-sounder on continuously?

5. If not, in what circumstances do you turn it on?

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?

Thanks in advance.
Click to expand...

Can I suggest using survey monkey (or similar) to create a survey and then posting the link? More likely to get responses I'd have thought.
 
SouthamptonStudent said:
I am student at the University of Southamptom, United-Kingdom, attending my fourth and final year of Acoustical Engineering. Me and two other students are currently working on a project aiming to design a "porpoise-friendly" echo-sounder for pleasure craft embarcations. In order to design a product that will also meet the demands of the customer, we want to understand those demands and know more about the use boat-owners make of their echo-sounders.

We would therefore appreciate if you could answer these few questions to help us with our project (if you have an echo-sounder).

1. What type/model of boat do you own?

2. How often do you use your boat?

3. What model is your echo-sounder?

4. When out to sea, do you have your echo-sounder on continuously?

5. If not, in what circumstances do you turn it on?

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?

Thanks in advance.
Click to expand...

1) Moody 31 Mk II
2) Every few weeks, for several days
3) Raymarine ST60
4) Yes
5) N/A
6) Yes. It is an aid to navigation; the water depths may be an important indication of position. It is not merely an indicator of shallow water, but also acts as a sanity check on other methods of position fixing.
7) Maybe, but it wouldn't be a priority (see below)

I have been in touch with experts on the effects of geophysical exploration on sea mammals, and it is clear that the effects on sea mammals happen at MUCH higher intensities than are generated by the depth sounders on small vessels. Therefore, I believe this to be a non-issue unless you can provide evidence to the contrary. Depth sounders emit very low intensity signals, at frequencies much higher than those emitted (and presumably perceived) by sea mammals.

Finally, I have frequently had porpoises near my vessel, and they usually appear to totally ignore the presence of my boat.
 
1. What type/model of boat do you own?
Moodt 31 mk II

2. How often do you use your boat?
most weekends (winter as well) and several weeks for summer holidays

3. What model is your echo-sounder?
Stowe

4. When out to sea, do you have your echo-sounder on continuously?
Yes, we sail on the East Coast - it would be a brave sailor to sail there without knowing the depth!

5. If not, in what circumstances do you turn it on?
N/A

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?
On the East Coast 5 m is deep!

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?

If I saw any evidence that echo-sounders damaged or even bothered porpoises, I might. Can you cite the scientific papers that say that is the case? I have frequently had porpoises around my boat (usually in the Baltic, but occasionally off the East Coast). They do not appear distressed by the echo sounder, and largely seem to ignore boats. Before you start this project, I suggest you make sure that there is a solid scientific reason to do this.
 
1. What type/model of boat do you own?
Hillyard 8 ton wooden-hulled sloop

2. How often do you use your boat?
Most weeks, winter included

3. What model is your echo-sounder?
Raymarine ST50 (range 0.8 to 180 metres)

4. When out to sea, do you have your echo-sounder on continuously?
No.

5. If not, in what circumstances do you turn it on?
When in shallows.

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?
NA.

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?
Only if it was demonstrated that echo-sounders in the 50 - 200 Khz range were porpoise un-friendly.

As others have reported, porpoises and dolphins do not appear to be put off by my E/S when in use.
 
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Thank you all for your replies.

The idea of the project comes from some EU directives for 2012 that were proposed about sound pollution in the ocean, and one of them was about high frequency impulsive sounds, such as echo-sounders, being disruptive to marine mammals (especially porpoises). However, these documents were not wrote by acousticians which is why part of our project is also trying to determine wether echo-sounders would actually be harmful/annoying to porpoises and other marine mammals. From my understanding, the reason it is suspected it might be disruptive to them is that porpoise echolocate(/communicate) at similar frequencies (115 kHz if I remember well) and their clicks are also narrow band short pulses.

So, thanks again, all the information is useful to us because we know little about boats. We knew that dolphins often came to play around boats but we heard that porpoise tend to have a very elusive behaviour.
 
I have to agree with the poster who said this is a non-issue.

Military sonars are probably a problem; not yacht depthsounders - which as far as I know operate on a pretty standard frequency & power.

Hence the ability to use most transducers with most sets, for example using a pre-existing transducer with a newly changed display unit, the difficulties only usually being special manufacturers' connections.

I was off Gorey, Jersey once when we saw a school of Porpoises about 1/4 mile away.

We deliberately turned on the depthsounder, and they altered course 90 degrees and came straight at us, eventually leading me to turn it off as I feared they were going to 'torpedo' us !

They then played with the bow wave for a while before going on their way.

Off Salcombe I had Dolphins playing in the bow wave as we motored in a flat calm, depthsounder on.

If anything I get the impression they think we're trying to communicate, certainly don't seem upset.
 
Sailing my own boat and doing deliveries.
Electronics are normally on whilst sailing so the echo sounder is active at all times.

I've had large Minke whale, porpoises, sei whale, dolphins, pilot whales all swim with us for some time under the boat or around the bow wave.

I've had a Sperm whale and calf almost pass under neath us on a collission course (it noticed us at 20 m and turned to shepherd the calf away from us) and killer whales on a route across our path not change course to swim under neath us.

I'm of the opinion from the above incidents that leisure units have little or no impact on cetacea, if it can be proved that leisure units do effect cetacea behaviour I would change or switch off when in deep water.
 
SouthamptonStudent said:
7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?

Thanks in advance.
Click to expand...

I believe I already do use a porpoise-friendly depth sounder. They certainly seem friendly around my boat, and I have my sounder on all the time (no separate switch for sounder - all instruments go on and off together). Is there any evidence - any at all - that current depth sounders are harmful to porpoises / dolphins / whales (or anything else for that matter)?

What do you think distinguishes a "porpoise friendly echo-sounder" from one that isn't "porpoise-friendly"?

Without trying to rain on your parade, it seems you are looking for a solution to a problem that doesn't exist.

Also - what is the relevance of the first (and even second) questions?
 
I have to agree with everyone else. My echo-sounder is always on when sailing. I have numerous photographs and videos of dolphins/porpoises swimming with us, in many waters between the Baltic and Greece. No evidence at all that they are bothered by the ultrasonics.

Dolphin numbers seem to be on the increase in many areas, e.g. Cardigan Bay, South Brittany. At the same time yacht numbers are also on the increase in those areas. So maybe depth sounders actually encourage them to breed? ;)
 
I have ultrasonic antifouling (far more audible than a echosounder) and pics of dolphins and basking sharks etc around our yacht. They didn't seem put off by the sound.

Considering the sound signature my yacht produces, I would have thought there would be more noise pollution caused by the engine of a coasters, cruise ships, bulk carriers and container ships. Yet dolphins etc are often seen playing in their bow wave.

If they were that bothered by unfriendly sound would they still do it?
 
I will start by answering the questions for you, hopefully it is some help....


1. What type/model of boat do you own?
Dehler 38

2. How often do you use your boat?
Every other week on average

3. What model is your echo-sounder?
Raymarine ST60

4. When out to sea, do you have your echo-sounder on continuously?
Yep

5. If not, in what circumstances do you turn it on?
see 4.

6. If you do, do you feel it is necessary to have the echo-sounder on continuously (for example, even in deep waters)?
Yep, no reason to turn it off.

7. If you were to replace your echo-sounder, do you think you might opt for a porpoise-friendly one if it were available?
No interest at all.


I really cant see the point in all this, i would suggest that it either harms/distresses them, and they would therefore simply swim away from the sound, or it seems more likely that it does them no harm at all they never seem bothered.

I would imagine there was hundereds of "better" projects to focus on, a forward looking depth sounder would be the most usefull, or some sort of power saving features (auto switch off at greater depths) etc etc

Hope that helps.
 
vyv_cox said:
Dolphin numbers seem to be on the increase in many areas, e.g. Cardigan Bay, South Brittany. At the same time yacht numbers are also on the increase in those areas. So maybe depth sounders actually encourage them to breed? ;)
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Maybe it's a disco-beat that draws them in.
Anyway, I reckon the lad has to show he's done some research with potential customers so he gets points for that section so here's mine:
Folkdancer 27
Out once a week on average throughout the year
Clipper echo sounder
Always switched on for reasons given by others
Might switch off if West of Canaries
I'd need to know more before buying
 
I´m surprised that noone has "What do you mean by dolphin friendly ?"
Do you mean some way of attracting dolphins ?
Do you mean frightening them away from potential danger ?
Do you mean specifically porpoises or all odontoceti because I think that many of us rarely diferentiate.
 
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Any boat I'm on will have the E/S on while underway(if it is functional), it's a nav instrument. I have encountered seals, porpoise, dolphins and killer whales while on passage, they did not appear distressed. I have also encountered seals, dolphins and porpoise while on boats not equipped with E/S, and their behaviour was not discernibly different, e.g. frolicking in the bow wave etc. I believe this is not an issue, existing E/S do not pose a danger to these beasties.
 
I only run the echo sounder if there is a particular reason to know the depth. That normally means when coming into an anchorage, although there are a few occasions when it's useful for navigation. I would only be interested in a porpoise friendly one if I saw hard evidence that existing ones were not porpoise friendly ... and that would have to mean rather more than having them go somewhere else for five minutes while I pass.
 
penfold said:
Any boat I'm on will have the E/S on while underway(if it is functional), it's a nav instrument. I have encountered seals, porpoise, dolphins and killer whales while on passage, they did not appear distressed. I have also encountered seals, dolphins and porpoise while on boats not equipped with E/S, and their behaviour was not discernibly different, e.g. frolicking in the bow wave etc. I believe this is not an issue, existing E/S do not pose a danger to these beasties.
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What behaviour does a distressed delphinidae display?
 
I suspect you're looking for an answer to a non-existent problem.

I frequently have had dolphins join my boat for up to 20' at a time - especially in the Irish Sea and St George's Channel - porpoises on the other hand keep themselves to themselves, might come and have a look but push off almost immediately.

I have on two occasions been "buzzed" by dolphins, their sound is very much louder and lower frequency than any transducer I have come across. (On both occasions it was a warning that I was setting into danger).

If anything I would say that they were attracted by the sound of the depth-sounder transducer.

Here in the Med, there are a different species of dolphin - not as frivolous or as friendly as our ones round UK waters - but they still come and swim with my boat.
 
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