Forward Looking Sonar

[miketucker]

I've been reading through a SN thread about disasters and near disasters, and read a couple of stories of boats that hit submerged or partially submerged floating hazards (cargo containers, sunken boats, whatever). It got me wondering about warning systems for debris in the water.

I did a quick google search and found one company (Interphase) that makes 'forward looking sonar' products that seem like they would do the trick. Price tag seems to be in the $1000+ range, which is steep but not outlandish. These can detect submerged obstacles, and also give you a depth contour of the bottom ahead of the boat, instead of right underneath it, which I think could be very useful.

Anyone have any experience with this type of equipment (from any manufacturer)? Any thoughts on why this isn't standard equipment on larger boats?

Mike

[Tynesider]

Hi Mike

You do not say what type of boat you have, I surveyed a Motor Sailer earlier this year for a buyer and was amazed to see the bow design, on close inspection I found this housed the 'forward looking sonar'.

I learnt from the seller he had mounted the sonar in various positions which is easier said then done!

When the boat is running on the engine only in reasonable flat weather it works fine, BUT when sailing it's a waist of space as the picture does not have a chance to steady.

Mike

[erps]

I met a fellow who had one on his boat last year and he loved it. He wasn't shy about checking out waters that were a little on the skinny side. It sounds like he typically used it when he knew things were skinny. We didn't talk about it's performance in deep open water. One thing I'd be interested in, is if it gets funny readings from thermoclines and different layers of water where fresh water mixes. Just with our standard depth sounder, sometimes we see depths of only five or six feet, when we're in deep water. Get's the adrenalin pumping a little bit when the alarm goes off and you see small numbers when there should be big ones.

[kd3pc]

neat gadget, but not ready for prime time on smaller, reactive sailboats...jitter and false returns. Power hogs for those who budget power while sailing

YMMV

[centaursailor]

I,d also checked out forward looking sonar,s on line but was put off by the price.
Near miss Monday night with the rocks just North of my local harbour due to a combination of tiredness after a weekend cruise, a broken(since early June) harbour sectored light and a high tide that put my usual 5 meter clearance contour further in than normal.
Luckily I was aware of the danger so was looking for the unlit danger marker when there it was dead ahead.
Would sonar have been better that the binoculars?
Safe sailing

[Minnewaska]

I didn't think forward sonar would really help with partially submerged debris.

[erps]

Here is one of the views. The other view looks kind of like a radar screen

[jrd22]

I would love to have one but from what I've seen and understand from Interphase is that you need to mount a fairly large bulb type ducer in front of the keel. I would worry about a log removing it and leaving a large hole in the hull. Of course if the sonar works perfectly I guess you would always "see" a partially submerged log and avoid it, but....

[Minnewaska]

Originally Posted by jrd22

.....Of course if the sonar works perfectly I guess you would always "see" a partially submerged log and avoid it, but....

It's not my understanding that this would be all that effective, but I've not used one in real time. First, the log is smaller than that school of bait fish and you might question what you see. The log or corner of that container may drift into your path and not be picked up at maximum range, which seems only a matter of seconds away. Finally, I'm not clear whether you can see the vertical and horizontal image simultaneously. A log that is just off center, with the pointy end toward your boat, is going to have a very small return, if any, on vertical, I would think. Would you turn to avoid every return: fish, flotsum, noise, etc.

These certainly seem helpful if trying to navigate a poorly marked or poorly charted shallow. Not so sure about logs.

[lancelot9898]

It's been awhile since I looked at these things, but the literature claims that it can see maybe a 1/4 mile ahead. Can't remember the exact number but it seems like it was a sufficient distance, however when looking into it futher that distance is based upon being in deep water. In shallow water when you really need it the distance is much less and almost useless. That was a few years back and probably new advances have been made in the recreational boating market.