simrad go7

[breezeblock]

had the boat out in the forth today for a bit of a jolly and were farting about with the settings and functions of it and after about 10 knots it was losing the depth signal and it wouldn't come back until you were almost stopped the sensor is mounted on the original position of the Garmin sensor so I am wondering if I need to move it down a few inches maybe a bit of turbulence from the back of the transom any thoughts the other problem we had was an issue of pressing the wrong thing on the touch screen when you are crashing about in the waves I think I would maybe have preferred something with buttons instead of the touch screen or as well as buttons

[jonp]

I would of thought it should be able to hold bottom at speeds well over 20kmts as my Lowrance has no problems (even in 300m+water).

Almost all problems come from transducer placement and angle. Firstly did the Garmin pick up at high speed? If so it may be that you just need to angle the transducer with a slight tilt forward and raise or lower it a small amount.

Not sure if the go model allows you to adjust ping speed in the menu or if it's just auto, if does allow you to manually set crank it up to its highest.

What frequency transducer are you using and what setting is the head unit on. The higher number such as 200htz is for shallower water, in saying that my unit will happily pick up bottom in water to 300m on 200htz.

The lower number like 50 or 83htz is a slower pulse for deep water and won't pick up as well with speed.

There are so many variables to take into account, a photo of the hull with a straight edge running from the hull to the transducer would help.

Jon

[paintman]

You could try mounting the transducer on a length of wood & using a g-cramp or similar to mount it to the transom. You can then try different heights/positions until you find the best.
If you need to fill the old screw holes temporarily then a stainless screw with the thread coated in sealant should do the job. For permanent I countersink & use a countersunk screw, also coated with sealant.

[breezeblock]

Originally Posted by jonp

I would of thought it should be able to hold bottom at speeds well over 20kmts as my Lowrance has no problems (even in 300m+water).

Almost all problems come from transducer placement and angle. Firstly did the Garmin pick up at high speed? If so it may be that you just need to angle the transducer with a slight tilt forward and raise or lower it a small amount.

Not sure if the go model allows you to adjust ping speed in the menu or if it's just auto, if does allow you to manually set crank it up to its highest.

What frequency transducer are you using and what setting is the head unit on. The higher number such as 200htz is for shallower water, in saying that my unit will happily pick up bottom in water to 300m on 200htz.

The lower number like 50 or 83htz is a slower pulse for deep water and won't pick up as well with speed.

There are so many variables to take into account, a photo of the hull with a straight edge running from the hull to the transducer would help.

Jon

the Garmin picked up until a slightly higher speed I think I will move the bracket down a bit to see what happens we tried various frequencies and from what I recall it never made much of a difference

[Last Tango]

Hi

Could be a "mode" issue. "Side scan" & "down scan" use 400 > 800Khz.
My Humminbird is good in standard modes at speed but "DownScan imaging" is best at low speeds (around 5kn). Not sure about the Simran but the digital depth readout on mine is the most "robust" as it auto-selects the best frequency for the conditions.
Double check the install instructions for the transducer, it's generally pretty close and you'd be talking millimetres rather than inches by way of adjustment from that.

[breezeblock]

I have maybe been thinking about it the wrong way I thought that depth was calculated on its own by its own frequency I didn't realise it used whatever frequency it was reading sonar from if that makes sense I will take a bracket with a different height with me next week when am out I just need to wade thru a pile of bolloxed stihl saws to get my own stuff done

[Last Tango]

Basic depth sounder uses one fixed frequency.... generally somewhere about 150 - 200Khz. transmits a tone burst and times the "echo" .

Generally the lower the frequency used the better depth penetration, but not so good for detail. Humminbird's "DownScan imaging" uses 400 or 800Hz for that (user selectable). Standard modes use a lower frequency either automatically or manually selected. (Medical sonars are in the Mhz range).
Down side of all this is you are trying to use the same transducer for multiple different frequencies so there's an element of compromise there...jack of all trades....etc. It's probably been optimised for the "side-scan" function so might not perform as well at depth as a "single frequency" transducer would.
Mines cr@p5 out at about 150mtrs (the manufacturers claim 300mtrs), but really, I don't care...... if it's that deep what's down there is kind of academic.

[Xk59D]

I'm curious to see your simrad, I was toying with getting 9 and maybe 5 versions to replace my garmins as I want structure scan for something to play with.......do I want it 1600 quid though......

Do you have the side scan transducer?

One issue I have is I literally have no idea where my transducer is, I know it is in there but it is an in Hull version so nothing sticks out anywhere. That would obviously need to be replaced with a transom mounted one for side scan.

[jonp]

Lets just step back a bit what transducer are you using and have you registered it in the sonar menu under installation ?

What depth and speed are you hoping to be able to use it in ?

Is the boat kept on the water or trailered ?

Side and downscan can pick up at high speed though you don't get the best from them unless you are travelling slower.

If you are using the longer down sidescan transducer you may find fitting it directly to the hull gives much better results. Doing it this way means you have to flip the left-right setting in the menu otherwise whats on the left show on the right on screen.

Simrad, Lowrance and B&G are all part of the Navico group so work much the same as well as mostly have the same connectors. (just saying as I use Lowrance).

Heres my transducer fitted to the bottom of my hull with a separate 200/ 50 htz to its right.

[jonp]

Originally Posted by Xk59D

I'm curious to see your simrad, I was toying with getting 9 and maybe 5 versions to replace my garmins as I want structure scan for something to play with.......do I want it 1600 quid though......

Do you have the side scan transducer?

One issue I have is I literally have no idea where my transducer is, I know it is in there but it is an in Hull version so nothing sticks out anywhere. That would obviously need to be replaced with a transom mounted one for side scan.

I wouldn't consider a 5 for any sidescan imaging. Go as wide as possible you wont regret it.

Simrad, lowrance and B&G are all part of Navico and basically quite similar to use (simple) fittings are much the same too, so often the same transducers can be used with them all.

My old hds worked well on the cheap 200/50htz with the 200 htz holding good bottom out to around 300m at speeds of 40kmh and the 50htz was good to around 700m at lower speeds.

Im hoping my new Gen 3 will be better in the deepwater, yes I do drop baits down 700m+ and fish in depths off 4000m chasing pelagic species.

My new hds unit picks up both down and sidescan at speed though the detail isnt as good as when travelling at 10 -15kmh. As a fisherman and diver sidescan has been a huge breakthrough for me. Being able to scan in detail 80m either side of the boat then place a waypoint over anything Ive picked up on screen is fantastic.

Old sonar on 200htz at 40kmh in 250m of water.



Dropping over the continental shelf (old unit)



Shallow wreck old unit



New gen 3 out for a test, note the mark showing on the rock to the right which shows full gps details on the left of the chart.



sidescan being overlaid onto map page (blue)

[breezeblock]

Originally Posted by jonp

Lets just step back a bit what transducer are you using and have you registered it in the sonar menu under installation ?

What depth and speed are you hoping to be able to use it in ?

Is the boat kept on the water or trailered ?

Side and downscan can pick up at high speed though you don't get the best from them unless you are travelling slower.

If you are using the longer down sidescan transducer you may find fitting it directly to the hull gives much better results. Doing it this way means you have to flip the left-right setting in the menu otherwise whats on the left show on the right on screen.

Simrad, Lowrance and B&G are all part of the Navico group so work much the same as well as mostly have the same connectors. (just saying as I use Lowrance).

Heres my transducer fitted to the bottom of my hull with a separate 200/ 50 htz to its right.

the sensor works well just not at higher speeds so I am presuming it is registered varying depths as I tend to go out in the forth and west coast Scotland so varying depths from 2m -100m there are quite a few wrecks that I want to have a look at for fishing the boat is trailered all the time and typically travelling along at 25-30knots it is the long side scan sensor but after having a look at your bottom mounted sensor I think mines is far too high

[Last Tango]

Originally Posted by Last Tango

DownScan imaging" uses 400 or 800Hz for that (user selectable).

Sorry......that's Khz not hz.

[Xk59D]

Originally Posted by jonp

I wouldn't consider a 5 for any sidescan imaging. Go as wide as possible you wont regret it.

I have a pair if plotters now so I would be getting a 5 and 9 to replace them, the 5 would be mostly for nmea data.

[Pikey Dave]

Originally Posted by jonp

I wouldn't consider a 5 for any sidescan imaging. Go as wide as possible you wont regret it.

Simrad, lowrance and B&G are all part of Navico and basically quite similar to use (simple) fittings are much the same too, so often the same transducers can be used with them all.

My old hds worked well on the cheap 200/50htz with the 200 htz holding good bottom out to around 300m at speeds of 40kmh and the 50htz was good to around 700m at lower speeds.

Im hoping my new Gen 3 will be better in the deepwater, yes I do drop baits down 700m+ and fish in depths off 4000m chasing pelagic species.

My new hds unit picks up both down and sidescan at speed though the detail isnt as good as when travelling at 10 -15kmh. As a fisherman and diver sidescan has been a huge breakthrough for me. Being able to scan in detail 80m either side of the boat then place a waypoint over anything Ive picked up on screen is fantastic.

Old sonar on 200htz at 40kmh in 250m of water.



Dropping over the continental shelf (old unit)



Shallow wreck old unit



New gen 3 out for a test, note the mark showing on the rock to the right which shows full gps details on the left of the chart.



sidescan being overlaid onto map page (blue)

Nice results Jon, I've been struggling to get similar results with my gen3 HDS. Re. The pic showing the transducer fixed to the keel, is that the new or old one? Any issues with spray or damage at speed?

[jonp]

Pikey Dave, that's the lss2 and no it doesn't make any spray at all, it also made no difference in any boat running performance having it set directly infront of the outboard.

When it was first fitted on the bracket it did make a huge spray and a spray shield was needed to stop the spray getting into the outboard cowling.

It's early days with the new gen 3 but so far I've been extremely impressed.

[jonp]

Originally Posted by Last Tango

Sorry......that's Khz not hz.

Thanks bud

[Pikey Dave]

Originally Posted by jonp

Pikey Dave, that's the lss2 and no it doesn't make any spray at all, it also made no difference in any boat running performance having it set directly infront of the outboard.

When it was first fitted on the bracket it did make a huge spray and a spray shield was needed to stop the spray getting into the outboard cowling.

It's early days with the new gen 3 but so far I've been extremely impressed.

That's the same transducer I have ( iss2) & I'm continually having to tilt it back down as it kicks up after any kind of landing. I'm also getting a lot of spray. I'll look at re-positioning next season, cheers [emoji106]

[breezeblock]

what a piece of crap its turned out to be currently sitting on my workbench to get returned to dealer tomorrow the touch screen has locked out completely and cannot navigate round about the controls page very disappointed with this