Transducer Placement Help

Having trouble getting transducer to read at speed. Bottom image becomes broken at 10-15 km/h. Transducer is m260 in hull in commodore 670 allrounder (hull design based on fraser if that helps).

New location at front of pic thru deck. Old location was in bilge between deckwash pump and bilge pump in photo.

Blue tape shows old location 700cm in from starboard side 400cm from rear

Blue tape in this pic shows new location 500cm in from starboard 1100cm from rear (can not go further in due to fuel tank)

600w transom mount also not reading well at speed. Blue tape shows original location done 100% to manufacturer specs. Actual location is an improvement but still not great. Blue tape on underside shows old in hull position. New positon is further forward just inside the chine

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Posts: 812

Date Joined: 09/10/06

 My wet box was setup where

Sat, 2015-08-29 13:00

 My wet box was setup where yours originally was, down near bilge in my northshore , thickest part of hull. Similar hull to commodores. Never had an issue .

Im surprised it wasnt working well there.

Are you going cut a hole in the kill tank and mount it under there?

Your 600w transom mount looks to low to me. I also had a tm 600w tranny on northshore and that also read great. I recon the  Front edge should be more level with hull l found. 

Posts: 14

Date Joined: 06/12/14

 Cheers holth. Not sure where

Sat, 2015-08-29 14:59

 Cheers holth. Not sure where to go to next just trying to gather as much info as possible. Maybe go back to the original position and try moving it left, right, back, forward. Problem is both locations are a tight fit with not a lot of room for adjustment. 

If I can't get the m260 right a tm260 might be on the cards or even the thru hulls (ss264 etc) seem popular. I would prefer to stick with the m260 though. Lots of options out there but as with all things boating this could get costly. 

The kill tank is between the driver and passenger seats so I thought that would be too far forward in the hull

just dhu it's picture

Posts: 1081

Date Joined: 14/05/09

Location

Sat, 2015-08-29 14:56

 the through hull tranny position is there any rakes in front of the position causing turbulence , I would have mounted it closer to the centre away from the existing rake shown ,  the rear tranny I would drop down until the fixing bracket is flush with bottom of hull to ensure clean water over the face.  iMO

Samo76's picture

Posts: 63

Date Joined: 17/08/08

Did you get that section

Sat, 2015-08-29 15:01

Did you get that section glassed in for the wet box Ranz? The area in the bilge won't work as there is a void between the bilge deck and the hull bottom, and yes agreed would drop the tm down more.

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 Here I am...and there you are.

Posts: 14

Date Joined: 06/12/14

 On the thru hull it is set

Sat, 2015-08-29 15:12

 On the thru hull it is set between the strakes. The closest one is 450cm in front of it to the left. So the tranny is not directly behind the strake at all. The shipwrights that installed it said he couldn't get it any further away from the rake it is near but I will go see him Monday and make sure this is or isn't an option. It's in an awkward spot so can't get a good picture

I wasn't sure whether to go up or down with the transom mount. Trial and error I guess. Do you you think it could benefit from left or right movement?

Posts: 14

Date Joined: 06/12/14

 Yes Samo got a shipwrights

Sat, 2015-08-29 15:22

 Yes Samo got a shipwrights to do it. The original bilge location all the timber and void was removed so was definitely on the glass hull. The original location was also done by a shipwrights but a different a couple years back when I got it. I put up with the broken image but after seeing mates boats performance and some Google research there is room for improvement 

Posts: 14

Date Joined: 06/12/14

 Hey Samo is that a commodore

Sat, 2015-08-29 15:59

 Hey Samo is that a commodore 670 in your pic. If so what transducer are you running and how does it perform

Samo76's picture

Posts: 63

Date Joined: 17/08/08

Yes mate, Ive got the tm258.

Sat, 2015-08-29 16:50

Yes mate, Ive got the tm258. I played around a fair bit with placement and looking at your pic probably about in between where you have yours and the tape from previous is where I ended up, just make sure its not inline with any strakes, the further down the better I think to ensure clean water over the face, the only downside would be a rooster tail but the swim step above will block that. I'm pretty happy with my performance, clear pic up to about 15-20kts, it does start breaking up above this but still reads ok. 

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Posts: 251

Date Joined: 28/07/11

 Can't help with the thru

Sat, 2015-08-29 18:21

 Can't help with the thru hull but I'd definitely be putting that transom mount bracket flush with the bottom of the hull as said earlier. I've tried 'manufacturers specs' before and never get as good a reading as when the bracket is as low as can go. Mines good up to 25 knots also.

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Posts: 1086

Date Joined: 10/05/14

 What did you fill the thru

Sat, 2015-08-29 18:32

 What did you fill the thru hull with?

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Date Joined: 06/12/14

 Thanks Samo good to know

Sat, 2015-08-29 18:46

 Thanks Samo good to know better results are definitely achievable 

Posts: 14

Date Joined: 06/12/14

 Filled the thru hull with

Sat, 2015-08-29 19:01

 Filled the thru hull with sea water originally. Now it has propylene glycol in it as per manufacturer specifications. No difference was noticed

Posts: 14

Date Joined: 06/12/14

Started new thread part 2 so

Sun, 2015-08-30 09:05

Started new thread part 2 so I could post new picture. Thanks for all the advice so far and any more is welcome

Once the transom mount is working well m260 wet box will be placed in front of this location or transom transducer may be upgraded to 1kw. Will also speak to shipwright that installed m260 for any additional ideas and local boat shop.