B164 Performance w/DFF1

[MarMax]

I've done a lot of searching and it seems that there is a consensus regarding a general dislike of the B164 transducer. Seems like all the recommendations go to the B260. Yet, the only combo transducer offered for the DFF3D contains a B164 along with the 3D array in a B260 housing. If the B164 is so bad, why put it in the combo transducer?

Looking a the Airmar data for the various transducers, they typically list in a Good-Better-Best manner based on the "Q" of each offering. Here's the 50/200 Q's and Beam Width's of several TDs from the Airmar publications.

-TD-------Q---------BW--
P66-----24/30---45/11---------GOOD
B117----28/30---45/12--------GOOD
B258-----9/15---15x21/3x5---BETTER
B164-----7/17---22x20/6x6---BETTER
B260-----8/8-----19/6----------BEST

Now looking at just the B164 and the B258, they seem pretty close with the B164 a bit better at 50kHz and the B258 a bit better at 200kHz. But the Airmar literature is still confusing in the comparison descriptions of the P66, B164 and B258. Quoting from the Airmar TM258 literature are the following comparisons:

Comparison TM258
Model------Rating-------Performance Increase
P66----------Good---------Benchmark model for comparison
TM258-------Better--------25x more sensitive at 50kHz and 16x more sensitive at 200kHz
TM260-------Best----------50x more sensitive at 50kHz and 13x more sensitive at 200kHz

And the B164 literature has the following comparisons:

Comparison B164
Model------Rating-------Performance Increase
B60(B117)-Good---------Benchmark model for comparison
B164-------Better--------6x more sensitive at 50kHz and 2x more sensitive at 200kHz
SS264-------Best----------50x more sensitive at 50kHz and 13x more sensitive at 200kHz

And now the really confusing part to me is that the P66 is slightly better than the B60(B117) and yet the TM258 is 25x/16x better than the P66. Now looking at the B164, it's only 6x/2x better than the B60(B117). The 50Khz Q of the B164 is better than the TM258 so how can the TM258 be 25x better than a P66 at 50Khz?

If you just consider Q it would seem the B164 should be more along the lines of 25x better than the B60(B117) at 50kHz and more like 10-12x better than the B60(B117) at 200kHz. I've always considered the B258/TM258 to be a really good transducer so it surprised me to see a lot of non-positive comments about the B164 on the board. Yes, in a perfect world we would all run a B260 with a high speed fairing with our DFF1, but sometimes we don't have the space for it.

Lots of blah, blah, blah above but it's necessary to get to the point of the matter. I'd like to get some better deep water performance and need to look at options for replacing the B117 with a 1kw transducer. In looking at my realistic options for a thru-hull transducer I can either keep the B117, replace the B117 with a B164, or replace the B117 with a 165T-B54 (no fairing) and use a TM260 instead of the TM54. I don't have the room for a thru-hull combo transducer as I'm limited to about 2-1/4" total height.

Thanks in advance for any thoughts/advice.

 

[Snips]

Marmax,
Is raising the bunks on your trailer an option? We have done this for some other installations to give more clearance for transducers.

Snips

 

[MarMax]

Snips, raising the bunks on my rig could probably be done, but it will exacerbate an already problematic situation with retrieving the boat. During launching and retrieval my boat likes to float up in the stern which makes it bow down in attitude. It's no so much a problem on launching as I've figured out a way to do a quick release. But on retrieval it's a different situation. Any increase in height of the bunks will make the retrieval situation more difficult. Hence my desire to keep the transducer height to about 3.25" maximum.

On my prior boat, a Parker 21 center console, I did have a B260 mounted in the high speed fairing, and I believe I trimmed the fairing down quite a bit. But I can't remember how much I trimmed it down. The B260 by itself is 2.6" high so perhaps you could trim the high speed fairing down to a height of 3.25". I'd look to you for recommendations as to how much you can trim a high speed fairing. Same goes with the 165T-B54 fairing block. The B54 is only 1.46" high so maybe the high speed fairing can be trimmed to 2" high. I would think a half inch of meat between the transducer and hull on a fairing would be sufficient.

And I would like some more technical feedback regarding the B164. Based on the Q it seems like it's quite an improvement over a B60(B117) and should be equivalent to a B258. The literature must be incorrect if the B164 50kHz Q is 7. This makes it slightly better than the B260 which is considered a broadband transducer. The reason I'm staying on the B164 clarification is if I can fit the B260 housing and fairing with some extreme trimming, I want to know that I'm going so see some significant improvement for the DFF1. I already know that the DFF3D will love the thru-hull in a high speed fairing.

 

[Snips]

Marmax,
If you put the B-164 next to the B-258 on a stationary platform I think you would be find their overall performance quite similar. However I would give the edge to the narrower beam pattern of the four element B-258 over the three element of the B-164. I also prefer the shape of the B-258 over the bell shaped B-164, which has had ringing issues in the past. You asked why we put the elements of the B-164 into the combo transducer for the DFF3D. It came down to internal spacing in using the B-260 housing, it would only allow for only a certain configuration of the elements. Transom transducers have there own set of issues and there is a article worth reading in this months Marine Electronic Journal about them.

Snips

 

[MarMax]

Thank you Snips, I've been doing my typical analysis paralysis over this issue and feel that although on this forum, the moderators are just ho hum about the B164, it's the least worst option for my situation. And based on its specs, it's a good performer.

Turbulence is the universal killer of transducer performance, so running a transducer in the most optimum conditions is to put it on the bottom flat of my Parker. Since I'm not one to cut lots of big holes in my boat, I most definitely won't be adding another hole, and the 2" hole that I currently have for the B117 will have to do.

Since I'd like to have the DFF3D performing the best and also want to have a 50/200 transducer, the only option is the 165T-50/200-SS260. To push me over the edge on this decision I was fortunate to find a fisherman that has a B164 installed on his Parker and has also had a B260 installed previously. He gives the B164 a big thumbs up, mainly because of its wider 200kHz beam and because he feels the 50kHz performance is a tad better than the B260.

He is also targeting two similar fishing scenarios. Bottom fishing in 200-400 feet and tuna fishing where he is looking at the top 200 feet of the water column. For both of these he likes the B164 better. Based on his screen shots, I'm inclined to agree.

As I mentioned previously, the Q of the B164 is one number better than the B260, so at least there is one fisherman out there that has confirmed it. Now why this is possible when the B260 has 7 elements and the B164 has 3 (for 50kHz), I can't explain. And the main beef (ringing) with the B164 is also reported to be much less or not present in the 165T-50/200-SS260, which is a good thing.

So I'll be shelling out about $2,500 very soon to replace a mint $1,500 165T-TM54 with the goal of extremely clean performance for my DFF3D and DFF1 (or TZT2).