Trimming a B260 HS Fairing

[MarMax]

I'd like to know how much a high speed fairing can be trimmed. This kinda relates to my other two transducer posts but is specific to the combo transducer or B260 housing in a high speed fairing. See the picture below and can I cut it to 3.5" total height?

I did cut down a B260 that was mounted on my prior boat, but I don't think I took it down to 3.5 inches. Probably more like 4 inches. Was originally thinking of cutting down a 165T-B54 fairing which at 3.5" leaves a lot more meat, but why not see if the ultimate transducer will work before going to plan B. This install will also require me to put in a 2" to 1" spacer since the existing thru hull hole is 2". But if the combo TD with a trimmed fairing will work and be structurally sound it's probably the best option.

 

[Johnny Electron]

I spoke with Airmar and there is no problem with your plan. That particular faring can be cut to a minimum thickness of 2 7/8". At that minimum height, there would be roughly 1/4" of material over the top of the transducer pocket. Your plan will give more material above the minimum which is good.

 

[MarMax]

Thanks for the information Johnny, much appreciated. Now I just need to scrape together my pennys and see if I can find someone that wants to buy a mint 165T-TM54.

And regarding the 1 inch transducer stem going through a 2 inch hole, do you have any specific recommendations? I was thinking of making a teak or mahogany spacer and just 5200 it in place like a sandwich between the fairing and the nut and use an oversize washer with the nut.

 

[Johnny Electron]

Your thoughts would work but I would discourage the wood. If it ever soaked up water and got rot, it wouldn't be great. A few of us talked it over and if you want to go that route we would suggest using an extra fairing block and cut out an insert that you can 4200 in place. The Airmar/Gemeco rep during our recent "Furuno Connections" video series recommended 4200. You have been a good customer and forum supporter. If you want to PM me your address; I would gladly ship you an extra fairing block that you can cut up for doing an insert. Another thought would be to put in a cut piece of metal pipe and filling in around it with something like this.

 

[MarMax]

OK, got it on the spacer material. I can buy a 1 foot piece of nylon tube/rod that's 2" OD and 1' ID and just cut it to match the hull thickness. I can 4200 the works together and then use a 2.5" OD by 1" ID heavy stainless washer under the nut. The spacer will then be sandwiched between the HS fairing and the SS washer.

The only down side is I'll probably not be able to sell the mint 165T-TM54 to offset some of the cost of the combo thru-hull.

Also, which I should probably ask in a new thread, is if the B164 part of the 165T-50/200-SS260 supports the bottom discrimination and rez-boost capability of the TZT2 sounder?

If the above is a no go, then I'd like to know if the TM260 works with bottom discrimination and rez-boost since it seems to be the same Airmar elements as the 526TID-HDD which is listed as bottom discrimination for the TZT2. Thanks again for all the great support.

 

[Johnny Electron]

... if the B164 part of the 165T-50/200-SS260 supports the bottom discrimination and rez-boost capability of the TZT2 sounder?

The B164 will not support BD in any form. The elements and beam angle just don't meet what they need for that function. No TM transducer will work for BD because of turbulence.

It sounds like a good plan on the transducer mounting.

 

[MarMax]

Thank you Johnny, as always, the information you provide is much appreciated. Kudos to you and all the fine Furuno staff that provide such great customer support!

 

[Johnny Electron]

:jump :jump Thanks

 

[MarMax]

Johnny, can you provide the dimension for the anti-rotation bolt from centerline of stem for both the B260 high-speed fairing and the 165T-B54 high-speed fairing? Thank you.

 

[Johnny Electron]

I am not entirely sure what measurement you are asking for. Can you draw it up exactly what you are asking for, like you did before in this thread? I will then ask Airmar for the measurements.

 

[Johnny Electron]

Is this the measurement you are looking for?
This is the one for the B260 if it is.

 

[MarMax]

Here is the same drawing with the dimension "X" in blue added. It's centerline of transducer stem to centerline of anti-rotation bolt. I'd like to know this for both high speed fairings. Would be ideal if it's the same. Thank you.

''

 

[MarMax]

Yes, that is it for the B260. Just need that same dimension for the 165T-B54 high speed fairing. Thanks.

 

[Johnny Electron]

I am checking with Airmar. What little info I could find is showing it is different. The old document shows 4.67" for "X". Please wait until I confirm.

 

[Johnny Electron]

Someone in the warehouse measured a 165T-B54 and X= 4.685" or 119mm

 

[MarMax]

Thank you Johnny! Now I just have to sell myself on the B164 elements inside the combo transducer. Can't seem to get off the fence and make a decision . . lol.