CHIRP Sonar for Better Anchoring

[Dockhead]

I'm replacing my dead Airmar CS4500 ultrasonic speed log with a DX900+ which does depth as well as speed, so I will have a free housing for some other instrument.


I've been thinking about CHIRP sonar so that I can image the bottom in unfamiliar anchorages. Anyone doing this? How well does it work? What gear are you using?


A lot of my cruising is on the Northern shore of the Baltic Sea, which is hella rocky, and I would really like to see if there are boulders in a spot I'm thinking about dropping in, for example.

[MicHughV]

I like to fish a lot.....even have my own fishing boat. It is equipped with the latest state of the art Garmin fish finder, it can do everything, except wash the dishes. The actual sounder is a multi-beam sounder, it can go deep, it can go shallow, it can go wide, it can go forward, it can provide stunning detail of anything and everything....including the bottom...

to quote :These include advanced CHIRP, traditional sonar and Garmin ClearVü™ and SideVü™ scanning sonar, which provides the clearest scanning sonar images on the water.

in clear-vu and side-vu mode, it can show with incredible detail, the bottom.... rocks, wrecks, holes, you name it....almost photographic quality...you can set the unit to look forward and to the side...different modes work better at different depths....

I can set the main screen to show the bottom in several different configurations simultaneously....all in dazzling color..

The main screen can be had in sizes 16" (400 mm) and smaller....a small size would easily fit on the steering binnacle. The performance is the same as the larger sizes, but obviously, with a small screen, detail is harder to see.
It can be seen in full daylight or night time...
It has a built in GPS, so with a press of a button, you can mark a spot, name it, and return to it.

My unit is a Garmin, but other fish finders claim much the same thing....They are a bit pricey, starting at about $1,000....that's just for the main unit...
The transducer is separate...about $500.....most transducers are made to fit on a fishing boat stern, but they also have thru' hull transducers.

Hope this helps..

[PirateGuy]

Hi Dockhead - saw your post on the other thread.

I’m a bit beat from dealing with a cursed new plumbing fitting most of the afternoon - I’ve been changing all my 40 y o (now brittle) copper plumbing to PEX, and decided to change faucets in the head and sinks in the galley too. What I thought was going to be a 4 day job has stretched to two weeks now.

CHIRP sonar? The function came with my RM ES97 MFD. While I worked as an engineer in the offshore oilfields around the world as a young man, I’ve been out of small boat sailing (never did any cruising) since the mid-1980’s.

Since I had the function paid for in the MFD, and being more than a bit of a gearhead, I bought an inexpensive CHIRP transducer to go with the MFD and had it thruhull mounted several haulouts ago. It doesn’t give me photographic views, nor side scan sonar like the other poster has on his boat, but depending on depth, I can resolve objects to about 6 inches (I’m guessing). My guess is calibrated to the anchor chain of small tankers that are often moored offloading on a channel I use. I can see the return off the chain links, if not the links themselves.
I don’t use the CHIRP sonar function unless I am anchoring. Where I cruise, there are sand bottoms, rock bottoms, and fields of smallish coral heads. I spent a rather unpleasant night after an unexpected wind event came up, and I dragged, but couldn’t raise anchor, so I motored into the wind for about 4 hrs with breakers 100 ft behind me, just so I could remain in place. I often cruise solo: When I raised anchor in the morning after the wind died down, I found a chunk of coral wedged into my Manson Supreme, preventing it from re-digging in.
The CHIRP sonar easily sees chunks of coral or rock:

[Dockhead]

Originally Posted by PirateGuy

Hi Dockhead - saw your post on the other thread.

I’m a bit beat from dealing with a cursed new plumbing fitting most of the afternoon - I’ve been changing all my 40 y o (now brittle) copper plumbing to PEX, and decided to change faucets in the head and sinks in the galley too. What I thought was going to be a 4 day job has stretched to two weeks now.

CHIRP sonar? The function came with my RM ES97 MFD. While I worked as an engineer in the offshore oilfields around the world as a young man, I’ve been out of small boat sailing (never did any cruising) since the mid-1980’s.

Since I had the function paid for in the MFD, and being more than a bit of a gearhead, I bought an inexpensive CHIRP transducer to go with the MFD and had it thruhull mounted several haulouts ago. It doesn’t give me photographic views, nor side scan sonar like the other poster has on his boat, but depending on depth, I can resolve objects to about 6 inches (I’m guessing). My guess is calibrated to the anchor chain of small tankers that are often moored offloading on a channel I use. I can see the return off the chain links, if not the links themselves.
I don’t use the CHIRP sonar function unless I am anchoring. Where I cruise, there are sand bottoms, rock bottoms, and fields of smallish coral heads. I spent a rather unpleasant night after an unexpected wind event came up, and I dragged, but couldn’t raise anchor, so I motored into the wind for about 4 hrs with breakers 100 ft behind me, just so I could remain in place. I often cruise solo: When I raised anchor in the morning after the wind died down, I found a chunk of coral wedged into my Manson Supreme, preventing it from re-digging in.
The CHIRP sonar easily sees chunks of coral or rock:

Sounds fantastic. What transducer are you using?


I have something called "Broadband Sonar" built into my B&G plotters. I think I need a black box besides a transducer, but maybe this is worth while.

[Rhapsody32]

One needs to consider the available transducers that would work with your specific MFD. On a sailboat, it would almost always be a thru-hull transducer. There are available In-hull transducers but limited in function. Airmar producers most of the transducers in the market, and they are MFD brand specific. Airmar recently introduced a line of smart electronic transducers that read depth, temperature, and speed (no paddle wheel). Forget SV (side view) on a sailboat, as these protrude a couple of inches outside the hull, hence, another drag source.

[RigBig]

I have three transducers in 36' sailboat. One is a shoot through medium CHIRP. Works well for seeing fish and depth. A chirp will not tell you the bottom material or if there are obstacles below. To see the bottom in detail, you would need side and bottom transducer.

[Dooglas]

I have a Garmin sonar/fishfinder with CHIRP/ClearVue technology. This has been a real step up from my previous sonar unit. Very clear and detailed view of the bottom. SideVue technology is also available and another step up IMO.

[Rhapsody32]

Garmin, Navico(B&G, Simrad & Lowrance), and Raymarine offer transducers with CHIRP for traditional and Clear View or Down View screen views. The latter is a structured view of the bottom, some include fish and some not. Side View is a split structured more defined view of the bottom. IMO for anchoring purposes, the Clear View/Down View is sufficient and saves $$$ over Side View transducers.

[PineyWoodsPete]

I'm looking at this 9" Garmin unit w/ transom-mount transducer for haulout this summer, as the '14 Raymarine 12" MFD has no fishfinder/CHIRP capability:
https://www.westmarine.com/buy/garmi...14?recordNum=1
The transducer alone is over $500

Anchoring down in the rocky Channel Is. can be challenging...

[StoneCrab]

Well this may be a stupid comment but the thought goes through my head everytime I look at these units....

Why is it that you can't have any detail from ahead of the boat?

These screens, like the one in the previous posted link all show a trough under your boat with beautiful representations of what is to the side of you. For my purposes, I really don't care much about what is to the side, I want to know what I'm about to hit or what I'm about to drop my anchor on top of.

I have dreams about dropping my anchor into a sunken boat's hold and I can't get it up..... be kind, now, lets not psychoanalyze that any further. I digress...

I've been looking at these units since my instruments may be older than me but back off of pulling the trigger for several reasons. Perhaps you guys can help me out.
1. Is there any possibility that I buy a transducer that is NOT compatible with my new $1000+ MFD? It seems that they are all made by Airmar.

2. Is there any possibility that I will be unable to buy charts for foreign destinations with any of these? I don't want to get sucked into one companies infrastructure only to find out that they don't cover that part of the world.

3. Since the transom mounted transducers seem to do it all at a reasonable price, I keep fantasizing about just building a streamlined fairing around a transom transducer and gluing to my keel. In my head, I've built this and installed it a hundred times. I cut the cable and pass it through a hole drilled in hull and attach a waterproof gland to the wire on the inside. Since there are no moving parts, I really don't need to be able to pull it out while I am on the move. Surely somebody had tried this.... bad idea? or you've tried it and it worked so well, you're keeping the secret to yourself?

4. Then there is the beer goggle thinking where I ask my buddies why people don't just turn the side scan sideways so you get that detailed picture of what is ahead of you. You know, servo mount that transom transducer so it scans like radar.

I do like the descriptions that some of you posted regarding the capabilities of your systems. I don't mind spending the money as long as I get it right. I hate the expensive mistakes based on marketing fluff.... and good documentation is so hard to come by now.

[CarlF]

In the marketing "fluff" department, I installed one of the very expensive forward looking Garmin Panoptix PS51 transducers. I had this fantasy of seeing rocks before I hit them.

The problem (and it was right in the Garmin description but I missed it so it's my own fault) is that it can only see forward 8 times the depth of the water. So if you draw 4ft and are looking for a 4ft rock you won't see it until it's just 32ft from the transducer - which on my boat was mounted 10ft from the bow to find a good mounting place.

So assuming I was staring at the screen constantly, I would have half a boat length to turn or stop after seeing the rock.

It also did not provide a "picture quality" view of the bottom like you see in the ads for the sideview systems.

[PirateGuy]

Originally Posted by Dockhead

Sounds fantastic. What transducer are you using?


I have something called "Broadband Sonar" built into my B&G plotters. I think I need a black box besides a transducer, but maybe this is worth while.

Another afternoon gone on chasing down plumbing fittings. At last all I have left it the galley sink drain.

The transducer I got was a simple downview. I choose it because it was compatible with the RM eS97 MFD I already had. I think the transducer was about $250 (US).
By my experience, rocks and coral heads larger than 6 inches in dimension are easily seen with this setup. Sand bottoms give a nice, bright return signal because of the abrupt change in density between water and sand. A soft clay or silt (mud) bottom should give a fuzzier return, because of the typically very high water contents of these types of soils, which lessens the density difference with water. I haven’t seen this yet on my CHIRP sonar display because soft mud is not typical of the anchorages I’ve been cruising since I implemented the sonar. I infer the “fuzzy”’ return on my 35+ years of occasionally doing seismic wave soil exploration.
You might “calibrate” or ground truth how sonar signal returns vary between sand and soft mud based on your own anchorage experiences. Again, rocks and coral are easy.
If you see a gently, sinosoidally undulating bottom be aware that you are probably seeing your own hull (and thus the sonar transducer) going up and down in the waves. You don’t have a fixed point reference so boat motion is also seen on your display.

[Dockhead]

Originally Posted by CarlF

In the marketing "fluff" department, I installed one of the very expensive forward looking Garmin Panoptix PS51 transducers. I had this fantasy of seeing rocks before I hit them.

The problem (and it was right in the Garmin description but I missed it so it's my own fault) is that it can only see forward 8 times the depth of the water. So if you draw 4ft and are looking for a 4ft rock you won't see it until it's just 32ft from the transducer - which on my boat was mounted 10ft from the bow to find a good mounting place.

So assuming I was staring at the screen constantly, I would have half a boat length to turn or stop after seeing the rock.

It also did not provide a "picture quality" view of the bottom like you see in the ads for the sideview systems.

Yeah, I know. My boat was built originally with an Echopilot Gold FLS forward looking sonar, with the large "professional" transducer.


Same deal with how far forward it looks. It actually IS useful, but in a very limited way, only when you are carefully picking your way through at very low speed and watching the display carefully.


But this is a different function than what I imagine for the fish finder. Seeing rocks before you get to them is one thing. Seeing the bottom and understanding what's down there, is something very different. If you can circle around over your potential spot, and get an idea whether it's clear down there or not, whether there are boulders or wrecks or junk, what the bottom appears to be made of -- that would be fantastically useful.

[Paul L]

Originally Posted by CarlF

In the marketing "fluff" department, I installed one of the very expensive forward looking Garmin Panoptix PS51 transducers. I had this fantasy of seeing rocks before I hit them.

The problem (and it was right in the Garmin description but I missed it so it's my own fault) is that it can only see forward 8 times the depth of the water. So if you draw 4ft and are looking for a 4ft rock you won't see it until it's just 32ft from the transducer - which on my boat was mounted 10ft from the bow to find a good mounting place.

So assuming I was staring at the screen constantly, I would have half a boat length to turn or stop after seeing the rock.

It also did not provide a "picture quality" view of the bottom like you see in the ads for the sideview systems.

This is less than the dedicated FLS systems, like the Echopilot that is 10 to 20 times depth.

[Compass790]

3. Since the transom mounted transducers seem to do it all at a reasonable price, I keep fantasizing about just building a streamlined fairing around a transom transducer and gluing to my keel. In my head, I've built this and installed it a hundred times. I cut the cable and pass it through a hole drilled in hull and attach a waterproof gland to the wire on the inside. Since there are no moving parts, I really don't need to be able to pull it out while I am on the move. Surely somebody had tried this.... bad idea? or you've tried it and it worked so well, you're keeping the secret to yourself?

4. Then there is the beer goggle thinking where I ask my buddies why people don't just turn the side scan sideways so you get that detailed picture of what is ahead of you. You know, servo mount that transom transducer so it scans like radar.

I do like the descriptions that some of you posted regarding the capabilities of your systems. I don't mind spending the money as long as I get it right. I hate the expensive mistakes based on marketing fluff.... and good documentation is so hard to come by now.[/QUOTE]


I like the way you are thinking in question 4Haven't tried that



But I can tell you I did put a transom mount transducer on the hull. Didnt cut the wire & had a big enough cutout in the hull to get the neck of the transducer inside the hull. Yes faired it with body filler as wanted minimum drag as yacht was used in racing as well as cruising.
Had no problems with that setup.


Sold that boat & next one I cut the stern mount transducer open ( not an easy task not to damage cabling) & glued it in an 1 &1/2" IIRC tank fitting or thru hull if you want to pay 4x more.
Cut a hole in hull with holesaw & installed tank fitting sealed with 4200.
Again worked a treat.


On a ladyfriends boat she objected to me cutting a slot in the hull to put her chirp transom mount transducer on so I just epoxied it to the solid grp hull & it still showed amazing detail.
Its supposed to degrade the performance firing the sound waves thru the hull but sadly I never tried it outside first so cannot compare.


We have an old school fishfinder but from what I've seen the modern stuff is way better. I'd buy a scanning sonar if I could.