Through Hull Transducer Mounting For Aluminum Alloy Boats

General boating discussion
ehsvp
Posts: 67
Joined: Wed May 05, 2010 6:13 am

Through Hull Transducer Mounting For Aluminum Alloy Boats

#1

Post by ehsvp » Sun Apr 29, 2018 5:00 am

I'm trying to decide what is the best way to install a through hull, flush mount transducer for my boat. It has 1/4" bottom plates and is very sturdy. I'm a little reluctant to drill over a 3" diameter hole in the hull for the transducer. I was wondering if anyone that has installed one strengthened the area around the hole? I'm going to be mounting the transducer about 3' in front of the outboards, near the keel of the boat.


Bob

Chaps
Donator '09
Posts: 2122
Joined: Sun Jan 13, 2008 12:19 am
Location: Seattle, WA

Re: Through Hull Transducer Mounting For Aluminum Alloy Boats

#2

Post by Chaps » Sun Apr 29, 2018 8:04 am

I work on lots of aluminum boat bottoms and have never seen an issue with large thru-hull transducers.
1987 24' LaConner pilothouse workboat, 225 Suzuki
Image
please view and like: https://www.facebook.com/bottompainting/

User avatar
welder
Site Admin
Posts: 4542
Joined: Thu Jan 03, 2008 11:51 pm
Location: Whitesboro, Texas
Contact:

Re: Through Hull Transducer Mounting For Aluminum Alloy Boats

#3

Post by welder » Sun Apr 29, 2018 9:14 am

Measure twice and cut once.
Lester,
PacificV2325, Honda BF225
2386

kmorin
Donator 08','09,'10,'11,'12,'13,'14,'15,'16,'17,'18'
Posts: 1338
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Through Hull Transducer Mounting For Aluminum Alloy Boats

#4

Post by kmorin » Sun Apr 29, 2018 12:11 pm

ehsvp,
the only possible risk to the hull from a penetration is that the lower profile of the transducer is taken off- by impact or grounding- and leaves the hole open or partially open to flood the hull.

Countering that- is the extremely low profile of most through hulls now. They are almost always only a 1/4" thick (often much less) below the hull- many less and the flange is highly tapered as a circular flange so there is almost no edge to tear against in impact. In almost every single 'worst case' you'd see the entire hull skid over the rock/bar/shoal and just slide over the transducer face- so..... most owners just cut the hull opening and install.

I did put several of these fittings in a well of pipe- where the hull was doubled in side- using another 'do-nut' of 1/4" about 2" wider on all sides than the opening- and welded a length of 4-5" pipe to the doubler- this created a well that was sealed on to with a bolt on flange. This method required making a wrench to tighten the nut inside the well around the threaded transducer riser- and a gland on the top flange for the cable to come out of the well.

TO my knowledge, this boat has never seen anything like a catastrophic collision needed to even scratch the transducer face !! let a lone the type of impact for which we protected the boat! but its there and it was the kind of install the owner preferred so we provided it.

My take is you'll be fine with a centerline or near centerline hole in the bottom and the regular (two or three step) install with 5200 + O-ring to seal the transducer to the hull- I'm assuming the vertical, plastic, threaded cylinder with a circular tapering flange outside the hull?

The only issue I've had to address was on boats with lots of deadrise I've had to cut the hull and put in a 'flat spot' for the transducer otherwise is would have served as 'side scan sonar'!! In the case of too much V to mount flat/vertical- I cut out a do-nut larger than the transducer by 2" and using 1/2" plate- put the plate in level- that leaves an 1/8" down outboard and an 1/8" up (depending on V/deadrise angles) toward the keel to get a "level" (at rest of running trimmed a couple degrees by the bow) surface to mount too. The welds of 1/4" to 1/2" plate reduce any 'edge' or thickness difference and welding inside and out insures integrity.

Just some other notes on mounting.

Cheers,
Kevin Morin
Kenai, AK
kmorin

ehsvp
Posts: 67
Joined: Wed May 05, 2010 6:13 am

Re: Through Hull Transducer Mounting For Aluminum Alloy Boats

#5

Post by ehsvp » Sun Apr 29, 2018 3:56 pm

Thanks for the replies everyone, much appreciated.

Post Reply Previous topicNext topic