Grady White 330 transducer placement

[sammyseal]

Hi All,

I have a Grady White 330 and have just installed a Furuno TZT package, part of this includes a thruhull Airmar ss264 transducer and a Furuno 86khz wet face transducer. The ss264 is mounted on the port hand side around 3’ 4” forward of the transom just inside the longitudinal girder. The Furuno transducer is mounted through the keelson on the planing strake around 2’ 8” from the transom.

The issue that we are having is that both transducers are getting aerated at around 15knots speed and losing the bottom.

Would sincerely appreciate if anyone can advise the best place to mount the transducers?

Cheers,
Sandy

 

[Doc Stressor]

Well, you never want to mount a transducer through a planning strake. The strake lifts the boat in part by channeling air underneath the hull. It's best to locate the transducers on an angled part of the hull using either a tilted element or a faring block.

I have my Airmar transducer located in the space behind the fresh water tank about 10" starboard of the centerline. That's about 2' from the transom. I can track bottom up to 35 mph if it is fairly calm.

 

[sammyseal]

Thank you Doc Stressor,

I read your post with great interest, thank you kindly. Is the boat you are referring to a Grady White 330 with a thru hull airmar transducer as well?

I'm most interest in rough water performance. How does it perform in these conditions?

Thanking you in advance!

 

[Doc Stressor]

I was referring to my 226. I have a Humminbird 998 fish finder connected to 2 transducers. An Airmar B60 mounted through the hull as I described and a transom mounted Humminbird XHS 9 HDSI 180 T. The Airmar can track bottom in seas up to a 2' Gulf chop (5 sec or less period). The bottom line appears broken, but I can read get the depth. The transom mounted transducer actually tracks bottom better than the through hull. I can track bottom at speeds up to 35 mph in any seas that I can stand. The trick was to mount it on a SternMate extension, which puts it a few inches behind the transom. It would not track bottom a speeds in excess of 15 mph when it was mounted flush on the transom. That's why I got the through hull Airmar. The Airmar is about twice as sensitive as the Humminbird transducer, but it seems to get more interference at higher speeds in a chop.

Transducer location is always a tricky game, especially on an SV2 hull. The forward strakes direct air under the rear of hull in strange ways. The problem with through hull transducers is that you have to make a guess about a location that should work OK. If it doesn't, you're stuck with a hole in your hull (although these can be filled fairly easily). The best thing to do is to try to find somebody with the same hull that you have and ask how their transducer location is working out. The other way to go is to get an in hull transducer such as an Airmar M260. These always seem to work. They are powerful and sensitive enough that the 30% attenuation you get from shooting through the hull doesn't make significant difference.

 

[Doc Stressor]

I just re-read your post.

The Airmar ss264 is essentially an M260 split into 2. You should have 2 through hull transducers, one for 50 kHz and one for 200 kHz. I am not familiar with the Furuno 86 kHz transducer, but I can't see how it can be paired with half of a ss264. Maybe that's your problem.

 

[sammyseal]

The boat has been installed with two separate transducers. The ss264 is a 1kW 200kHz wide beam transducer for scanning bottom in relatively shallow depths (up to 300 feet). The other transducer is a commercial grade 2kW transducer for really deep water, say 1,500 feet. Both are plugged into a Furuno DFF3 network sounder which caters precisely for this setup. The two transducers work independently for different fishing scenarios. Both work fine in calm conditions and slow speed (less than 15knots), however it is the combination of speed and not calm seas that causes the issue.

As you have correctly identified, the location of the transducer appears to be the key consideration. I noted with interest your success with the transom mount extension for the transducer. Given the depths I'm fishing a in hull would not be ideal given the transducer sensitivity I require.

I would be interested in any others owners of a GW330 that have mounted thru hull transducers and share with me the best place to install them.

Thanking all in advance!