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update on best current tranduc/head unit combo1kw

Printed From: The Fishing Website
Category: General Forums
Forum Name: The Boat Shed
Forum Description: Discuss all things boating.
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=139151
Printed Date: 28 Jan 2026 at 12:47am


Topic: update on best current tranduc/head unit combo1kw
Posted By: inanga
Subject: update on best current tranduc/head unit combo1kw
Date Posted: 06 Apr 2025 at 5:42pm
It's time to update the sounder/head unit on the boat which is an older 26 foot fibreglass seaswirl trailer boat.  I am looking at a 1kw tranducer and headunit, and it would be nice to have a combo that has the capability to add a sender unit in the future but not essential.  Preferably a transom fitted tranducer/s.  

The boat will fish out of tairua at any depth from the shallows out to deep drops, with am emphasis on deep water capabilities.  Side scan would be ok but I've had it on previous boats and didn't find it useful most of the time!  So not really worried about that.

Boat show time approaching so any opinions or experience on this topic?



Replies:
Posted By: BotStomper
Date Posted: 08 Apr 2025 at 5:38pm
You would have a hard time beating a Airmar TM275LH-W driven by a Simrad S5100 and displayed on a Simrad NSS - I see they've just come out with the NSS 4 so there might be some good deals around on the very capable NSS Evo 3. The high/wide is good out to circa 150m with the Low coming into its own beyond that; you can also use the much narrower beamwidth of the Low Chirp to pinpoint fish a bit better.

You could ditch the S5100 as the NSS can drive dual channel CHIRP at 1kw but you get more oomf in deeper water with a dedicated sonar module.

Best bang for buck is the TM185M; the medium frequency is decent for anything from 0m to maybe 300 but doesn't really specialise at anything. We run both a TM275LH-W and TM185M all driven by a S5100 and the 185M does a superb job from about 50-150m.


Posted By: inanga
Date Posted: 09 Apr 2025 at 7:24pm
thanks for the advice sounds like a good place to start.  I'll keep an out eye out to see if there are any specials around the boat show.  

What sort of depths have you found this set up can maintain good definition for bait fish and predators?Are there any weak points you've found with this arrangement?  cheers


Posted By: Tzer
Date Posted: 10 Apr 2025 at 5:50am
If your handy to Tauranga call in and see Micheal Whonsedler at Bay Marine Electronics. 
http://baymarineelectronics.co.nz/" rel="nofollow - http://baymarineelectronics.co.nz/


Posted By: BotStomper
Date Posted: 10 Apr 2025 at 4:10pm
We're running a slightly different display setup with twin Lowrance HDS units but for all intents and purposes the sonar part is the same. We can mark individual fish on the bottom in 200-250, and easily locate the deep scattering layer/bait at 400+; I've never marked predatory fish at that sort of depth but we don't do much of that kind of fishing and I haven't taken the time to tune the settings for it - for what it's worth, if you're fishing that deep you've got to be comfortable deep in the menus of your unit because in my experience nothing on the market will give you good results at 400+ when set to "auto".

The 25 degree wide beam on the 275LH-W can be a mixed blessing. It is very good for finding the general area fish are in but it can difficult to pinpoint fish if they're very localised - in 90m you're seeing a 40m circle on the bottom so you could be marking a lovely fish that's 20m to one side of you.

We often lose the bottom momentarily when backing up to manage our line angle when deep dropping, especially when it's choppy. This is somewhat just the reality of transom-mount transducers, but is probably exacerbated by the relatively small boat meaning the transducers are fairly close to the prop.


Posted By: out2sea
Date Posted: 10 Apr 2025 at 4:35pm
Best to talk to the pro's, plenty of options to choose from at the boat show to discuss your requirements.

I brought a new simrad 15 inch ultrawide unit and 1kW transducer through Advanced Trident at the boatshow last year and saved almost $2000 from the rrp. They were great to deal with.

Botstompers recommendation is pretty much the go to for Deepwater and game fishing but if you are serious about deepdropping then stepping up to a 2kW transducer could be an option.

The TM275 HW-L is generally used by game fisherman as the High chirp has the same wide cone angle as the Low channel so good for finding bait in the upper water column with excellent definition just not the depth penetration of the low. It could also be useful in shallow water for covering a larger area finding fish. The alternative is the traditional High chirp which has a much narrower cone angle and is better for pinpointing schools of fish.


Posted By: krow
Date Posted: 10 Apr 2025 at 8:33pm
I have a nss evo3 with 275lhw. without the s5100 and I'm not super impressed with it but it's ok Bait school at 18 knots.
This is a rather large Mako we hooked.




Posted By: kimber7wsm
Date Posted: 11 Apr 2025 at 6:01am
Hi, I have a 265H/l and a 175m, with Simrad Evo 3 (I swap the transducers). I would strongly recommend a Low/ Medium model. I've found fish to 350m with the medium and I find it good when trawling In fact I like it from 0 to 450m. If you combine as a L/M the low will give you wide although nowhere the detail of the high/w. I know several others who consider the low/med the best combo. Some of them are very good fishers.

If you want to regularly drop to 400m plus then you really need 2 or 3kw.

When traveling change the frequency to the highest fixed one you have. Fixed is way better than chirp at 20kn plus.



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