B275lhw vs B265lh (if you plan on Dfff3D)

[ToddF]

Hello

I'm planning for DFF3D and a new Chirp sounder, most likely tZt3. I'll either do combination pocket mount or two separate transducers depending on my installers advise. I'm trying to decide between the High Wide frequency of the B275lhw vs the Narrower High frequency of the B265lh if I go with DFF3D.

I typically fish

Winter:
-10'-150' for lobsters where pinpointing small rocks, seaweed, and ledges is very important
-200'-600' for bottom fish where pinpointing rocky reef structure is primary, and fish ID a second

Summer:
-50'-150' Surface fishing. Fish are suspended so primary is bait/fish orientation and beam width, Second is Target ID.
-Offshore in thousands of feet of water but most activity is in 50-200' with max relevant depth maybe around 400'. Boat speeds range from 3 to 14 knts. Width of beam and bait/fish orientation are primary. Target separation secondary, and no need for bottom detection.

I'm leaning toward the B265lh because of the narrow cone angle in high for my winter fishing since I plan on DFF3d which already has an even wider beam than High Wide. That said, with the large range of frequencies in High Wide (vs Low), I'm betting the target ID and amount of info transmitted is pretty awesome. If for some reason I couldn't do Dff3d, the B275lhw becomes very attractive.

But assuming I can do DFF3d. How would the 25 deg cone angle of the High Wide compare to the 25 deg cone angle of the low when suface fishing or offshore? Seems like the wider range of frequencies and higher frequencies would mean more detail on the High Wide but would you consider the 25 deg Low chirp much inferior to the 25 deg High Wide in those summer applications?

Thanks

 

[Deep Blue]

ToddF,

What transducers were you considering. Separate transducers or the Combination transducers..?

- Deep Blue :think

 

[ToddF]

Most likely 2 separate transducers

165T-B54 (Dff3d)
and either B275lhw or B265lh

If I went with pocket mount, same 165t-B54 with one of the above Chirp transducers built in so

165T/265LH-PM488-12P
or 165T/275LH-PM488 - 12P

I don't have a flat keel so the transducers will be about a foot off centerline forward of the single inboard shaft seal on opposite sides of the centerline.

I'm imagining a pocket mount combo transducer will require extensive fiberglass work for me building a pocket inside hull, but if I'm wrong, I'd like to know because one hole is attractive over two.

 

[Deep Blue]

ToddF,

Pocket Mount Transducers do have an advantage over Single Transducers that several transducer elements are installed within a single Pocket Mount transducer housing.

However, you are correct that it requires that a custom fiberglass pocket to be constructed in your vessel’s hull or the keel, and flush to the surface. A majority of sportfishing vessels have been going this route as a way in keeping those transducers that are installed at a minimum, and combating any potential turbulence issues by having multiple transducers.

- Deep Blue

 

[ToddF]

Thanks. If I can make it work I'll go with the pocket mount. I should know if its doable this week. Appreciate your input.

How about the B275lhw on a boat with Dff3d? Is this advantageous to have 25 deg of beam width when you'd presumably have 120 deg with Dff3d? Or would it make more sense to have the narrow detailed beam of a B265lh for somebody who does spend half the year bottom fishing?

 

[Deep Blue]

ToddF,

I'm not a big fan at running both the wide DFF3D (165kHz) beam, along with the B275LH-W (42-65kHz on Low Frequency / 150-250kHz on the High Frequency) on the same boat.

If you have the DFF3D, then you already have the wide beam sonar covered, as the B275LH-W will only provide you a 500ft depth while using it's High Frequency 25 x 25 degree constant beam width, where the DFF3D can provide you little more deeper depth at 900ft with it's 120 degree wide beam.

I would tend to lean more using the DFF3D, and the B265LH as the better route. The B265LH uses 42-65kHz 25 x 16 degree beam width on Low Frequency, and 10 x 6 degree beam width on the 130-210kHz High Frequency. Using this combination, you'll still have better overall coverage using both these transducers.

- Deep Blue :wink7

 

[ToddF]

Thank you. The narrow beam of the b265lh (in high) seems a great supplement to the Dff3D. Appreciate your input.

 

[Capt. Jack Sparrow]

ToddF,

I'm not a big fan at running both the wide DFF3D (165kHz) beam, along with the B275LH-W (42-65kHz on Low Frequency / 150-250kHz on the High Frequency) on the same boat.

If you have the DFF3D, then you already have the wide beam sonar covered, as the B275LH-W will only provide you a 500ft depth while using it's High Frequency 25 x 25 degree constant beam width, where the DFF3D can provide you little more deeper depth at 900ft with it's 120 degree wide beam.

I would tend to lean more using the DFF3D, and the B265LH as the better route. The B265LH uses 42-65kHz 25 x 16 degree beam width on Low Frequency, and 10 x 6 degree beam width on the 130-210kHz High Frequency. Using this combination, you'll still have better overall coverage using both these transducers.

- Deep Blue :wink7

this is the exact 'ducer combination that I'm using and I'm very happy.

 

[Keta]

Something to consider. As I understand it the B265LH works with Accu-Fish and bottom discrimination. The B275LH-W doesn't for either, Accu-Fish and bottom discrimination. Is this correct. Anyway something to consider especially if you're interested in bottom discrimination.