Transom mounted transducer on 21SE modified hull.

[Westerly Fluke Guy]

I am thinking of pulling the trigger on a Garmin all-in-one transom mount for my 1243xsv.
The boat came with a B60 mounted thru hull.
Will I have any problems with a transom mount due to the modified hull design?
Thanks in advance for your replies.

 

[John G]

I have a 23SE with the same thru hull transducer and a Garmin 7 inch chart plotter. I recently installed a Garmin GPS Map 1042xsv with the GT52HW-TM transom mounted transducer. I used a transom saver for mounting the new transducer. Garmin has a good guide for mounting the transducer (https://static.garmin.com/pumac/Transducer_Placement_Guide_EN-US.pdf). I kept the old system as a backup and to allow me to avoid using split screen on the 1042xsv to see charts and sonar simultaneously.

I had no problems due to the hull design of the SE. The new equipment works well though there are two issues I am still working to fix. First is that a significant rooster tail develops from the new transducer at planing speeds. This sends a lot of water up along the outside of the outboard. While the spray doesn't reach the air intakes it does constantly bath the cowling junction in salt water. I've tried raising and lowering the transducer which had limited impact on the rooster tail. I reached out to Garmin who recommended a Garmin-made transducer spray deflector but I found the deflector has the same profile as my transducer. That profile leaves a gap between the transducer and the transom hull/transom saver of about an inch. That seems to be where the rooster tail originates. Next step is to lengthen the deflector to close that gap and see if that solves the problem.

The second problem which doesn't seem like it will be an issue for you, is that in water over about 20 ft. with both transducers operating the 1042xsv picks up interference from the B60. I think this is just the new transducer picking up the bottom echo from the B60 and that there is probably no solution other than to turn off the B60. Unfortunately there is no feature on the old chartplotter to do this without physically disconnecting the transducer.

 

[Westerly Fluke Guy]

I have a 23SE with the same thru hull transducer and a Garmin 7 inch chart plotter. I recently installed a Garmin GPS Map 1042xsv with the GT52HW-TM transom mounted transducer. I used a transom saver for mounting the new transducer. Garmin has a good guide for mounting the transducer (https://static.garmin.com/pumac/Transducer_Placement_Guide_EN-US.pdf). I kept the old system as a backup and to allow me to avoid using split screen on the 1042xsv to see charts and sonar simultaneously.

I had no problems due to the hull design of the SE. The new equipment works well though there are two issues I am still working to fix. First is that a significant rooster tail develops from the new transducer at planing speeds. This sends a lot of water up along the outside of the outboard. While the spray doesn't reach the air intakes it does constantly bath the cowling junction in salt water. I've tried raising and lowering the transducer which had limited impact on the rooster tail. I reached out to Garmin who recommended a Garmin-made transducer spray deflector but I found the deflector has the same profile as my transducer. That profile leaves a gap between the transducer and the transom hull/transom saver of about an inch. That seems to be where the rooster tail originates. Next step is to lengthen the deflector to close that gap and see if that solves the problem.

The second problem which doesn't seem like it will be an issue for you, is that in water over about 20 ft. with both transducers operating the 1042xsv picks up interference from the B60. I think this is just the new transducer picking up the bottom echo from the B60 and that there is probably no solution other than to turn off the B60. Unfortunately there is no feature on the old chartplotter to do this without physically disconnecting the transducer.

I most likely would completely disconnect the B60 if I went with the all in one transducer.
I previously had two sonar units on a boat and one always messed with the other.

Please update us if you solve the constant spray on the engine issue.
That is of concern to me.

Thx. for the reply.

 

[warthog5]

B60 is a 600watt unit and transmits in 50/200Hz. The new unit is Chirp..It covers many Frequencies, But 50 & 200 are mixed in there.. This is why the problems.

The logical move and what I would do is Remove the B60.... open the hole to 3 3/4in and install a B175M - 1000watt unit. Then you don't have those unsightly cables going over the transom and you have a 1000 W. CHIRP X-Ducer. I've done it several times.

 

[Westerly Fluke Guy]

B60 is a 600watt unit and transmits in 50/200Hz. The new unit is Chirp..It covers many Frequencies, But 50 & 200 are mixed in there.. This is why the problems.

The logical move and what I would do is Remove the B60.... open the hole to 3 3/4in and install a B175M - 1000watt unit. Then you don't have those unsightly cables going over the transom and you have a 1000 W. CHIRP X-Ducer. I've done it several times.

That was my first thought as it would be easy like you described. And I wouldn't have a bunch of junk either glued / screwed and cables secured to the transom. However
I'm interested in side scan.

Is the Chirp really worth the upgrade?

It would be really convenient if they would simply produce a Chirp transducer in the same footprint as the B60

 

[warthog5]

They Do Produce a Chirp in the same fooprint. B75. https://www.airmar.com/Catalog/Marine/Chirp-ready/Thru-hull/B75H

It's not sidescan.... It's what you have now, only enhanced.

The 1243xsv is a CHIRP unit, BUT if the X-Ducer B60 is NOT CHIRP it will only function as 200/50Hz.

This will give you a thruhull and CHIRP, But first you will need to repair the hole in the hull. You want a 9 to 1 taper. IE: 1/2in thick hull gets ground back from the inside 4 1/2in and tapers down at the middle. Using round cut fiberglass disc's laminated in the hull. Then the X-Ducer mount is cut on a bandsaw the same angle as the hull. half of it inside the hull the other half outside the hull. The actuall X-Ducer sits in a pocket on the outside piece.

https://www.garmin.com/en-US/p/540990
Next question....... How deep do you fish? Sidescan has a Max of about 100ft.

 

[Westerly Fluke Guy]

They Do Produce a Chirp in the same fooprint. B75. https://www.airmar.com/Catalog/Marine/Chirp-ready/Thru-hull/B75H

It's not sidescan.... It's what you have now, only enhanced.

The 1243xsv is a CHIRP unit, BUT if the X-Ducer B60 is NOT CHIRP it will only function as 200/50Hz.

This will give you a thruhull and CHIRP, But first you will need to repair the hole in the hull. You want a 9 to 1 taper. IE: 1/2in thick hull gets ground back from the inside 4 1/2in and tapers down at the middle. Using round cut fiberglass disc's laminated in the hull. Then the X-Ducer mount is cut on a bandsaw the same angle as the hull. half of it inside the hull the other half outside the hull. The actuall X-Ducer sits in a pocket on the outside piece.

https://www.garmin.com/en-US/p/540990
Next question....... How deep do you fish? Sidescan has a Max of about 100ft.

I can’t simply enlarge the hole that is there for the B60 and purchase a 75H for the correct angle?

 

[warthog5]

Yes you can. Hole in there now is 2.250 in...... Hole for B75H is 2.60in.

You asked about Sidescan.... The B75H is Not sidescan.

The question about How deep you normally fish was Never answered.

 

[Westerly Fluke Guy]

Yes you can. Hole in there now is 2.250 in...... Hole for B75H is 2.60in.

You asked about Sidescan.... The B75H is Not sidescan.

The question about How deep you normally fish was Never answered.

I probably won't benefit that much from side scan as most of my fishing is between 60-150ft.
I thought the B75H was almost a 4" hole.
I will have to look further and probably upgrade to the B75H.

 

[warthog5]

Well 1st it's Not a B75H ........ It is a B175 H you are thinking of and it's Not a 4in hole it is a 3 3/4in hole.

You are confusing the B75H [600 watt] with the B175H [1000 watt]

2 completely different X-Ducers.

 

[Westerly Fluke Guy]

Well 1st it's Not a B75H ........ It is a B175 H you are thinking of and it's Not a 4in hole it is a 3 3/4in hole.

You are confusing the B75H [600 watt] with the B175H [1000 watt]

2 completely different X-Ducers.

Yes, I meant approximately 4" (which is what 3-3/4" is)
The B75H is just a fraction larger than the B60 and 600W.
I am looking into what real benefit I would gain from the 175H.
Probably only depth (power) which I will never need. Unless of course we are talking the 175HW which only has a 500' depth range.

 

[southofblock]

Chirp is worth it! It is called pulse compression and provides tremendous improvement in resolution.

 

[southofblock]

Airmar's B175M would be a significant step up in performance (and expense), heck of a transducer, wish I had one. This unit would increase your resolution as well, though the 1000 Watts would be overkill in 200' or less water column. Bigger hole in hull.

 

[Westerly Fluke Guy]

Airmar's B175M would be a significant step up in performance (and expense), heck of a transducer, wish I had one. This unit would increase your resolution as well, though the 1000 Watts would be overkill in 200' or less water column. Bigger hole in hull.

I was thinking of a B75H which would be closer to the actual size of the penetration which already exists in my hull. Any reason to doubt it too wouldn't be a big increase in resolution and performance?

 

[southofblock]

No, no reason to doubt.

The 'beam width' of a transducer decreases with increasing array aperture (the black face of the transducer) and increasing transmit frequencies. Ideally you want the ducer to generate a very narrow pencil beam (that is the goal of the sidescan units). So, the relatively much wider B175M naturally generates a narrower beam, providing a significant improvement in resolution. Resolution here referring to the ability to distinguish between red blobs versus well defined, separated, classic arch returns from individual, for example, striped bass. Or, bottom features. (I do not know what fluke returns look like, sea bass are distinctive). I would expect that B175M chirp would be an additional gain in resolution (over the B75H). I do not believe that you will be disappointed with either. I have a B75M, and fish the same waters, works fine for me. That said, my engineer geeking would like the bigger and more powerful B175M.

 

[Westerly Fluke Guy]

No, no reason to doubt.

The 'beam width' of a transducer decreases with increasing array aperture (the black face of the transducer) and increasing transmit frequencies. Ideally you want the ducer to generate a very narrow pencil beam (that is the goal of the sidescan units). So, the relatively much wider B175M naturally generates a narrower beam, providing a significant improvement in resolution. Resolution here referring to the ability to distinguish between red blobs versus well defined, separated, classic arch returns from individual, for example, striped bass. Or, bottom features. (I do not know what fluke returns look like, sea bass are distinctive). I would expect that B175M chirp would be an additional gain in resolution (over the B75H). I do not believe that you will be disappointed with either. I have a B75M, and fish the same waters, works fine for me. That said, my engineer geeking would like the bigger and more powerful B175M.

Why the "M" over the "H" ?

 

[southofblock]

I occasionally head out to shipping channel and deeper water, and was concerned about signal attenuation at the higher frequency bandwidth. In hindsight, since travel out 70 miles rarely, likely should of chosen the b75h.

BTW, search the hull truth and Airmar b75m versus b175hw , shows actual screenshots

 

[Westerly Fluke Guy]

I will do that.
I have also thought about that transducer and I think Idon't want to open up the hole in the hull that big but then I ask myself. Why not?

I occasionally head out to shipping channel and deeper water, and was concerned about signal attenuation at the higher frequency bandwidth. In hindsight, since travel out 70 miles rarely, likely should of chosen the b75h.

BTW, search the hull truth and Airmar b75m versus b175hw , shows actual screenshots

 

[warthog5]

FYI: I was one of the first to install a B60 when they came out. Airmar had a ad on their site..... COMING Soon.. That ad was up for 2yrs, as I waited with baited Breath. I had a thread I started back then when I finally got it on The Hull Truth.... Owned by other people then and more fun. That thread got to be 8pages long.

Today the Go to X-ducer hands down for my area...[Pensacola,Fl.] is the B175M.

 

[Westerly Fluke Guy]

FYI: I was one of the first to install a B60 when they came out. Airmar had a ad on their site..... COMING Soon.. That ad was up for 2yrs, as I waited with baited Breath. I had a thread I started back then when I finally got it on The Hull Truth.... Owned by other people then and more fun. That thread got to be 8pages long.

Today the Go to X-ducer hands down for my area...[Pensacola,Fl.] is the B175M.

It seems you have either upgraded to or changed out quite a few thru hulls over your tenure. What is the cabling route from the bilge area where the B60 now sits on my 21SE back up to the console? The small cable seems to be routed up to the starboard side way back with the engine wiring but from there how does it make it's path under the deck. My trolling motor power cable went up the channel for the fuel fill but there is no channel on the starboard side. Hopefully its not all tie wrapped together and fed through with the engine wiring so it can't be removed or re-fit. It's getting around to winterizing tasks and I haven't really looked closely at it yet.

On a separate note, my coastal fishing along the RI coast and out to Montauk and Block Island probably would never take me to waters deeper than 250ft. and that would be rare. 95% of the time I would be in 145 or shallower, sometimes Summer flounder are on the beaches and in holes at 15ft.
My average would probably be 75-80.