Simrad Sounder that Reliably Finds Bottom

Hello Trawler Forum. I love this site and I've been a lurker for years, but now I now I need to trouble you for guidance.

My 2012 Helmsman Trawler 37 Sedan came with an all Simrad electronics suite that I've been mostly happy with except for the sounder. On our trip up the BC Sunshine Coast into Desolation sounds last summer, I would lose depth readings at the most inopportune moments (inevitably feeling out the bottom in a tight unfamiliar anchorage). I would like to upgrade either the transducer or sounder module or both to improve reliability, but I don't know which component (neither or both?) is causing the problem. Before I start guessing and end up poorer and unsatisfied, I'm hoping someone has had a similar experience that I can learn from. My sounder module is the Simrad BSM-1 and the transducer is an Airmar B744V.

Scouring the Internet has yielded little helpful information. There's lots of talk about fish finding, but I'm not a fisherman. I just want rock-solid depth readings. Failed readings in Puget Sound have been rare for me so perhaps there's something about thermal layers or bottom composition up north that confused my sounder.

Many thanks to anyone with relevant experience.
Tim

Greetings,
Welcome aboard. No bother/trouble at all...

My first suggestion would be to make sure you have all the latest software for your BSM-1, and for your NSS or NSO or whichever chart plotter you have. There have been a lot of software issues with Simrad sounders and MFDs over the past year or two. I haven't followed it closely, but noted a lot of issues. I don't know what the current state is, but making sure you have the latest software is a first step.

If that doesn't work, I'd suggest not wasting any time and get a Furuno FCV-628. It's a small, inexpensive fish finder that works really well, and should connect right up to your transducer, though some wire splicing may be required. I beat my head against the wall with a variety of Simrad equipment, sounders included, and the best thing I did was get rid of it.

Tim I'm no expert but it sounds like a transducer problem to me. The first thing I would do is clean all the connectors and plugs.
There is a chap on the Hull Truth web site who frequents the electronics forum with the user name of Abbor. He really is an expert and seems to know all there is to know about Simrad gear. I'd give him a try with your problem.

I'm just installing my first Simrad item, a GO9 with a P79 transducer so hoping it will all work as advertised,

Brett

Jetstream and twistedtree, thanks for the pointers.

My MFD software (NSE12) is definitely up to date, but Simrad doesn't offer a downloadable update for the BSM-1. Regardless, I've seen other posts about applying BSM-1 patches so I've contacted Simrad. Hopefully they'll send me an image. Would be great if that fixed the problem, but didn't introduce a new bug (hmmm...).

I'll check out the Hull Truth. Abbor seems to be a Simrad expert/advocate.

Talk to Simrad and/or a knowledgeable Simrad tech.

Capt.Bill11 said:

Talk to Simrad and/or a knowledgeable Simrad tech.

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+1 Call Simrad. Where is your transducer mounted and how?

Chaumu, The BSM is a fishfinder that needs power for fish discrimination. You are using the B744 transducer which means you,re using 600 watts. That's overkill to see the bottom in shallow water. You can probably tweak the gain on your 200 kHz frequency setting & get a better bottom return in shallow water but honestly that's not what it was designed for. It was designed to find fish & see the bottom in deeper water. The best shallow water depth finder is a low power, inexpensive depth indicator. Hawkeye & Faria make a small round digital display that will fit into a standard 2" gauge hole or a simple digital readout like the Raymarine I40 would work too. All come with a glue-in, shoot-thru-the-hull transducer option so you wouldn't even need to haul your boat to install the system (provided your hull isn't a cored hull). Good luck.

I would say if you are loosing bottom only in shallow bays, especially in the summer, your sensitivity may be picking up a thermocline that is close to your bottom and the sounder (all sounders) will loose bottom.

You might have to play with gain and filters, usually the instruction manual discusses this. If not, try the Airmar website, I believe it did at one time.

Make sure you are on 200hz only and not dual.

We have this same issue sometimes. For us it is interference from the other fathometer (depth sounders, fish finders, flasher, etc etc). We have 1 POS unit that just gives depth at each helm and 1 ff/chartplotter at each helm. In shallow water, and once in a while in deeper water, they will "hear" each other. do you have any other units? You should check the frequencies each is using. if they are the same, you might have found your issue.

boomerang said:

Chaumu, The BSM is a fishfinder that needs power for fish discrimination. You are using the B744 transducer which means you,re using 600 watts. That's overkill to see the bottom in shallow water. You can probably tweak the gain on your 200 kHz frequency setting & get a better bottom return in shallow water but honestly that's not what it was designed for. It was designed to find fish & see the bottom in deeper water. The best shallow water depth finder is a low power, inexpensive depth indicator. Hawkeye & Faria make a small round digital display that will fit into a standard 2" gauge hole or a simple digital readout like the Raymarine I40 would work too. All come with a glue-in, shoot-thru-the-hull transducer option so you wouldn't even need to haul your boat to install the system (provided your hull isn't a cored hull). Good luck.

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FWIW, I had an awful time with the Hawkeye. Tried two units and two transducers and just wouldn't work.... engines on/off, holding the transducer in the water, etc. Support was by email and a PITA. Airmar support was excellent but not for Hawkeye.

Do you have the Raymarine? Looks like a nice unit.

boomerang said:

Chaumu, The BSM is a fishfinder that needs power for fish discrimination. You are using the B744 transducer which means you,re using 600 watts. That's overkill to see the bottom in shallow water. You can probably tweak the gain on your 200 kHz frequency setting & get a better bottom return in shallow water but honestly that's not what it was designed for. It was designed to find fish & see the bottom in deeper water. The best shallow water depth finder is a low power, inexpensive depth indicator. Hawkeye & Faria make a small round digital display that will fit into a standard 2" gauge hole or a simple digital readout like the Raymarine I40 would work too. All come with a glue-in, shoot-thru-the-hull transducer option so you wouldn't even need to haul your boat to install the system (provided your hull isn't a cored hull). Good luck.

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You are being too charitable with Simrad! There is no excuse for this! The unit should automatically shift frequencies when moving into shallow water. I can understand loosing bottom when you are at the far end of the sonar's range, or due to thermocline, halocline, freshwater lens, entrained bubbles, etc. but not shallow water. Oh, and BTW, I can see fish just fine, near bottom when travelling upstream in the Fraser River, and I've never moved off the automatic setting on my Raymarine DS 600, during the past 4 years.

JDCAVE said:

You are being too charitable with Simrad! There is no excuse for this! The unit should automatically shift frequencies when moving into shallow water. I can understand loosing bottom when you are at the far end of the sonar's range, or due to thermocline, halocline, freshwater lens, entrained bubbles, etc. but not shallow water. Oh, and BTW, I can see fish just fine, near bottom when travelling upstream in the Fraser River, and I've never moved off the automatic setting on my Raymarine DS 600, during the past 4 years.

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Our Furuno doesn't always shift automatically.

Larry M said:

Our Furuno doesn't always shift automatically.

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I'd look to see if you can switch over to an automatic setting. Either way the unit is on the wrong frequency, or the gain is set too high. I'd be surprised if there a thermocline, halocline anything else that would overwhelm the strong signal of bottom in 50 feet of water--perhaps when you are in 500 feet but not 50 feet.

Another thought: What is the depth scale that is displayed on the sounder when this occurs? If the depth scale is down to 500' and you are in <50, it might be that the bottom is lost in the surface trace on the display.

A comment has been made WRT the transducer: If the unit is working in deeper water, that suggests to me this is not a connectivity or transducer issue.

Jim

BTW, how shallow is shallow in this case? At what depth are you losing bottom?

The only times I've lost bottom have been when the transducer is maybe 1-2' off the bottom, i.e. I'm about to run aground.

JDCAVE said:

I'd look to see if you can switch over to an automatic setting. Either way the unit is on the wrong frequency, or the gain is set too high. I'd be surprised if there a thermocline, halocline anything else that would overwhelm the strong signal of bottom in 50 feet of water--perhaps when you are in 500 feet but not 50 feet.

Another thought: What is the depth scale that is displayed on the sounder when this occurs? If the depth scale is down to 500' and you are in <50, it might be that the bottom is lost in the surface trace on the display.

A comment has been made WRT the transducer: If the unit is working in deeper water, that suggests to me this is not a connectivity or transducer issue.

Jim

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You might be suprised, but thermocline and different salinity, even currents carrying different amounts of silt and trash will make sounders lose signal if on the wrong setting.

Even older Furuno had several different settings such that fishing would drop off quite a bit due to sensitivity and frequency where the cruising setting would keep locked on fairly well.

twistedtree said:

BTW, how shallow is shallow in this case? At what depth are you losing bottom?

The only times I've lost bottom have been when the transducer is maybe 1-2' off the bottom, i.e. I'm about to run aground.

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, but even 5 or so feet may be in that troublesome range depending on settings.

psneeld said:

You might be suprised...

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You're right. I would be surprised. I do not believe the OP's problem to be due to halocline or thermocline issues. Maybe in very deep water, but not in <50 foot water. Something else is going on.

See for example Figure 18 of PSC Tech Report 16 (of which I was a co-author).

Technical Report Series | Pacific Salmon Commission

You will note that bottom is visible even through the interference of the turbulent zone in the channel off the right bank of the Fraser River. The river bottom has a very high target strength and the bottom trace is clearly visible. Fish targets in the turbulent zone are difficult to discern, however, the bottom is always visible.

Jim

Well, be suprised all you want.

I was a marine electronics installer for 4 or 5 years and dealt with it quite often.

Plus I have run as many as several hundred boats in a year while working for a boat dealership.

There are times in shallow water where you can clearly see a break in the water column, the digital number on the screen is intermittent and so is the bottom.

Frequency change or isolation sometimes helps if incorrect and so does filtering and gain. But in depths less than 15 feet or so true water depth, and a few less because of ducer placement, there are huge number of complaints about losing bottom for the reasons that others have explained to me including representatives from all the major marine electronics corps.

psneeld said:

Well, be suprised all you want.

I was a marine electronics installer for 4 or 5 years and dealt with it quite often.

Plus I have run as many as several hundred boats in a year while working for a boat dealership.

There are times in shallow water where you can clearly see a break in the water column, the digital number on the screen is intermittent and so is the bottom.

Frequency change or isolation sometimes helps if incorrect and so does filtering and gain. But in depths less than 15 feet or so true water depth, and a few less because of ducer placement, there are huge number of complaints about losing bottom for the reasons that others have explained to me including representatives from all the major marine electronics corps.

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Well bully for you! Since we are discussing our bonafides, I administered the hydroacoustics program of the Pacific Salmon Commission for 25 years, with a staff of 20 technicians, biologists and research scientists: A properly tuned, properly installed echosounder should have no problem showing a clear bottom trace in shallow water in all but the most extreme environments. The unit on my vessel has had no difficulty penetrating the halocline, or the turbulence zone in the Fraser River, even during high debris events, or freshet. Different story in deep water.

Jim

Had the same problem with several brands. Simple numer display has never worked for me in shallow often stirred up by and aerated boat wakes, FL water. I switched to scrolling double frequency fish finder, I dont fish, and the results were much better. even if there was not enough signal return to give a numeric display the scrolling display still showed some estimate of bottom profile.

JDCAVE.....Did you just say properly tuned, and installed echosounder?

I repeatedly said adjustments may fix the issue rather than replace as some offered.

Simple fixes first.

That seems to be the overwhelming experience I have heard from others bayview.....

Wifey B: Testosterone overload alert. Glad they're just comparing their credentials and not the size of their......you know.

Just teasing you guys.

I have a Raymarine suite. Two E80s networked together with radar, sounder and autopilot. I totally lost bottom in 2011 on my dsm30 and had the unit replaced on warranty. This last Sept I again totally lost bottom at the dock in Sydney. It said no data if I remember correctly. Fortunately I had a back up Lowrance sounder independently wired.

A few days later I did a hard reboot of my sounder modual by removing and replacing the undamaged fuse. It worked perfectly after that.

Hmmm. I'd say that was about 4' up the wall vs 3'-6". Can we have another round? Best 2 out of 3?

I have had several different brands of commercial grade echosounders on my fishing vessels over a 34 yr span and I have lost bottom on all the brands in shallow waters (under 5 fa) but only while in reverse. Obvious the loss of bottom was due to heavy aeration caused by prop wash over the transducer. Very easy to pinpoint the cause under these conditions. In the Seattle area there are several marine electronics suppliers that also have technicians on staff that service the equipment. Simple matter to bring your sounder in to one of them and have them check it out if your sounder loses bottom at random, unexplained times.

Tim,
I had a similar problem with my Simrad NSO evo2 install. I had the P79 in-hull that would lose depth sometimes when things got shallow. I spoke with Simrad sales at the Miami show and they had a solution. The Bronze HDI 0 Degree Tilt Transducer 50/200 455/800. We did the Loop this year and were in many shallow anchorages. The new transducer never lost the bottom, we got down to less than 6 inches below the hull and the system showed it the whole way.

I concur. I have a new Simrad with their transducer and we never loose the bottom.

Great tips. Thanks everyone. A couple follow ups incorporating the points above:

Simrad tech support says there is no software update for the BSM-1 (just the BSM-2 and BSM-3). They did, however, ask me some follow up questions so they seem genuinely interested in helping. Wasn't expecting that. I'll keep this thread posted with their guidance.

I operated at both 50kHz and 200kHz and both were unreliable. I'm not certain if I was in dual mode, but I did adjust the gain and there weren't any relevant filter options.

I have no other fishfinders/sounders to cause interference but my current experience is motivating me to install a backup...

I too have experienced the lost signal when <5' away from running aground. Fortunately this isn't the experience I'm having. The depth I'm failing in is <100', usually <50'

The prop wash in reverse is a super interesting theory and one that is blessedly easy to test. I'll give it a try.

At the risk of stoking the spirited debate above, I suspect that thermal differences, salinity or some other kind of stratification is getting picked up, but it may not be relevant to my zero reading problem. I have seen the depth reading briefly bounce to 10' while not moving in 25' of water (anchored and stern tied). It freaked me out so I walked the perimeter with a lead line to confirm 25'. While it bounced around, I could see the bottom plot in the sounder view of my MFD jump up and back down again. Playing around with gain and other settings had no effect to eliminate the bounce. I had a couple similar experiences while underway in 1,500' of water. The readings jumped up to 10' feet for many minutes before finding bottom or reading nothing (expected in the extreme depths at the time).

The water column can be stratified and it is often suggested that in addition to thermocline and salinity and currents, different amounts of debris tend to stratify in some of those other layers which presumably adds to the jumping around of readings.

Some models do better than others even within a manufacturers line of sounders, some just seem to be "bottom losers" more than others.

On the Furuno 1850 on the Sea Tow boat I ran for 13 years, by the end, the internal battery was dying and it became extrodinarily bad at keeping bottom. The winter after I quit full time, they replaced the battery, and during the few part time tows I did last summer, it seemed MUCH better.

As many complaints as many boat owners have about the same problem, with reports that they have tried every troubleshooting trick, and still have the problem..... I don't think there is one clear cut answer to solve anyones sounder issue.