transducers

Bertramp · Post by **Bertramp** » Sep 18th, '10, 08:06

My boat is a 1970 Bahia and seems to have never had a depth finder. I want/need one. I also hate extra holes in boats.
Can a transom mounted transducer work on a 31 ?
How are the in hull transducers ?
If I go with a thru-hull (which I would rather not), where and how is best placement ?

thanks

Charlie J · Post by **Charlie J** » Sep 18th, '10, 08:31

go with the transducer that shoots thru the hull, some members have them, ill let them carry on

Preston Burrows · Post by **Preston Burrows** » Sep 18th, '10, 09:15

As a back up to my thru-hull transducer I 'glassed on an oak mounting pad onto the transom of my B28 and installed a transom mounted transducer...............which has worked there fine for me since 2005.

I dare say the 'hydro dynamics' of a B31's hull are not too different than a B28 with respect to transom mounted transducers / inboards and the transducers performance.................that said I'm only interested in readings of 6 foot depths or less at hull speeds of 22 knots or less.........

Brewster Minton · Post by **Brewster Minton** » Sep 18th, '10, 09:56

I think it depends on what you use it for or want it for. If for fishing offshore, a high power unit, I would think thru hull. Just riding around to see the depth, transom is ok. Transom might not be great if your landing big fish, one more thing to catch line on.

Carl · Post by **Carl** » Sep 18th, '10, 11:18

My main unit is a Bronze Thru Hull, I'll never do a plastic one again..but that's a story for another day...okay fine here's the story in a nut shell.

Hit a small piece of wood and depth finder crapped out. Opened the hatch to check and see it, seemed fine, gave a tug..didn't move figured it just got whacked and died. Ordered a new one...made arrangements for a short haul out and then proceeded to use the boat. A few days later it comes in I get hauled...I can't find the transducer under the hull...I look closer and then see entire bottom just sheared away...with my little finger I just touched the 1" Transducer stem, sending it right up into the boat.

Back on track...I got a good deal on a GPS Chartplotter with Sonar capabilities, came with a Transom mount Transducer. Just for giggles I tossed it in a bag of water and laid it in the bilge. I'll be dammed if it does not work as good as my Thru hull Furuno unit. I believe they lose some power shooting thru the hull...but it really serves my purpose and no holes.

JohnCranston · Post by **JohnCranston** » Sep 18th, '10, 12:15

Sim,
Good story. I'm getting ready to buy a 1kw transducer for my Garmin 3210 and I need to see down to 700 ft. Will yoursshoot down that far? Please elaborate a little more on how you set up your bag system.
Many thanks.
John.

Carl · Post by **Carl** » Sep 19th, '10, 09:25

John,
My honest answer is I have no idea how it would perform in 700'.

90% of my fishing is in Raritan Bay in 20-30' of water with Ship channels going down to 60-ish. For me it works perfect, especially in the shallow areas. The Furuno gets all wonky in less then 10' especially when moving fast. The other 10% is inshore/offshore for Shark & Tuna...but with gassers I only go out to about 250' of water. It seemed to be working fine, but I use the Chartplotter aspect of the unit more out there...other then reading a bottom depth which coincided with the Furuno Depth Finder I could not say if it worked as good as the thru hull.

As for my installation procedure....kind of embarrassing so don't tell anyone...Take the provided transom mount Transducer and toss into a Freezer Bag, add water to cover, grab a twist tie and tie off the top of the bag...open hatch and place in bilge. Check readings...if good snake wire up from bilge as you would for a normal install. To avoid transducer movement, (although it has never moved) this year I added a screw to a bulkhead, to which I attach the transducer cord with a twist tie.
Not the best method I'm sure...but I got a great deal on the GPS/Sonar package and figured I just wouldn't use the Sonar part...Transducer was in the box...one thing lead to another and found it worked real well for me...so now I have an additional depth finder.

I learned the water baggy thing with my in Hull Puck install for the tower Depthfinder. The said to do that to find the best location. Worked great in the bag of water...worked great when I first epoxied the puck in place then the signal degraded as the epoxy dried.

As my Traducer is quite portable...I played with it over the side and in the hull...I could not see a difference in readings...you could always try that before mounting. I think you can also mount in a waterbox filled with mineral oil...I thought about doing that...but I like my little baggy....I laugh every-time I open the hatch.

In Memory Walter K · Post by **In Memory Walter K** » Sep 19th, '10, 09:56

I have an Airmar in-hull in my B-20. You could probably make one to accommodate your transducer. I originally used mineral oil, but Airmar now recommends using straight antifreeze. I think the mineral oil was discovered to have an adverse effect on the O-ring sealing gasket. The important thing as I understand it is to use something that does not create bubbles in rough seas.

JohnCranston · Post by **JohnCranston** » Sep 19th, '10, 10:57

Sim,
Wow! I wish that everything, boat related, was that easy. I'll keep it a secret. Thanks.
Walter,
I'm glad that you told me about the antifreeze. I used mineral oil last time around.
Thanks.

Ken Hudson · Post by **Ken Hudson** » Sep 19th, '10, 11:36

John,

I have two sounders. One is inexpensive with a through hull mounted about 3/4's forward on the port bow. It was there when I bought the boat. Works great, so I left it.

I installed Furuno NavNet 3D wih their sounder. The transducer is 'through hull'. It is glassed to the hull about 3/4's aft on the stbd side. It is about a foot outboard of the shaft log. Works flawlessly right up to max...28 KTS.

The transducers come in severel angles depending upon deadrise. I chose 26 degrees.

It is interesting, on the mooring or at low speed, allowing for the difference in transducer mounting, both units are very close.

I can't speak to transom mounts, but I would suspect that turbulence would be a consideration.

Transducers, wherever mounted, need clear water.

Ken

In Memory of Vicroy · Post by **In Memory of Vicroy** » Sep 19th, '10, 18:01

I've got a Garmin 2010C with their sounder black box and the hockey puck shoot-thru-the-hull 'ducer in a mineral oil-filled 24 degree cylinder attached to the inside of the hull under the salon deck about a foot outboard of the keel. It will flawlessly track the bottom at 24 kts up to about 250 feet, and going slow to about 400 feet. I have a Sitex color sounder also with a bronze thru hull 'ducer and it will see the bottom in about 800 feet.

For shallow and medium depths the Garmin can't be beat.....even allows you to establish an underwater waypoint to come back to a bottom feature.

The in-hull ducer cylinder is attached to the hull with 4200. I ground the glass in that area with an 80 grit disc, cleaned it up with acetone before applying the 4200......use the cylinder as a guide and mark two concectric circles with a marks-a-lot and run your 4200 beads around them, then just stick it down....let it cure a day or 2 then fill with mineral oil. I did the zip lock full of water deal to test my spot first.

UV

Tony Meola · Post by **Tony Meola** » Sep 19th, '10, 21:39

Sim

A number of years ago we had a similar experiance to you. Had a Furono paper recorder at the time. We were in the Hudson Canyon and my Dad was running the boat. We were trolling when I heard something rolling under the hull. A piece of wood loaded with nails popped up in te prop wash. The Depth finder quit at the same time. We chaled it up to the depth finder just crapping out.

When we pulled the boat, the center of the transducer, that is the area that sends the signal was gone. Only thing keeping the water out was the stem and the gasket around it. We figured that piece of wood popped it out.

coolair · Post by **coolair** » Sep 19th, '10, 22:32

John, bertramp
I have a air mar M260 right now with my Garmin
It does pretty good, unless you are tryin to do crazy stuff and spot single fish at high speed the in hulls work just fine. but they are expensive.
I am probably going to try thru hull eventually. I originally installed a straight 200hz 1kw thru hull for a furuno. But to my surprise my wife went and bought me garmin stuff and the the furuno transducer isnt compatible with garmin sounder.
With the Furuno and there 4 thousand dollar sounder my bro can spot snapper at like 30 knots +

gplume · Post by **gplume** » Sep 20th, '10, 06:03

Anyone out there have experience with the airmar tilted units, which allow you to compensate for the dead rise. I am told the unitis mounted on an angle in the thru hull, so you just moun it flush, and don't compensate for the deadrise.

I was told to use an e 66087 for the b 31

In Memory Walter K · Post by **In Memory Walter K** » Sep 20th, '10, 09:08

I put one in my B-20 and it works fine. Put it in with 4200 and filled it with Antufreeze. The cable is attached to the transducer/cap, which snaps on and you can twist it to various degrees that are marked on the edge.

Carl · Post by **Carl** » Sep 20th, '10, 12:07

JohnCranston wrote:Sim,
Wow! I wish that everything, boat related, was that easy.

That's only because if it didn't work I would have tossed it in the closet and never given it another thought. I only wanted the Unit for the GPS Chartplotter.

I don't need another "Okay Depthfinder"...happy it worked, cool toy to play with as it has the Fisheye 3D cartography, but haven't really found it useful...other then a snicker when I think about it.

Carl · Post by **Carl** » Sep 20th, '10, 13:28

Tony Meola wrote:Sim

A number of years ago we had a similar experiance to you. Had a Furono paper recorder at the time. We were in the Hudson Canyon and my Dad was running the boat. We were trolling when I heard something rolling under the hull. A piece of wood loaded with nails popped up in te prop wash. The Depth finder quit at the same time. We chaled it up to the depth finder just crapping out.

When we pulled the boat, the center of the transducer, that is the area that sends the signal was gone. Only thing keeping the water out was the stem and the gasket around it. We figured that piece of wood popped it out.

Scary...I broke out into a sweat when it just fell in. I had the boat out with friends and their kids fishing in less then perfect conditions over the course of the few days it took to get the new transducer in. Not to mention the nights in the slip without attendants.

In Memory Walter K · Post by **In Memory Walter K** » Sep 20th, '10, 18:00

Frayed Knot almost sank a few weeks ago off Montauk because his transducer fell through! Ran through the harbor on plane to the travel lift. We ran all the way to Greenport and back for the Rendezvous just the week before. If it had happened en route either way it would have been bye bye.

Bertramp · Post by **Bertramp** » Sep 20th, '10, 19:08

I ran a B28 that I once owned halfway down LI Sound, through "the gut" and inside the Sag Harbor breakwater and under the bridge all on plane and straight to the travel lift due to a lost bottom of transducer.
Funny ... on plane, you don't get much water, but the minute you go to idle you get water FAST.

Brewster Minton · Post by **Brewster Minton** » Sep 20th, '10, 20:01

I have balsa dowls for each through hull. Strung next to each.

Marlin · Post by **Marlin** » Sep 20th, '10, 20:14

I'm installing a depth sounder to tell me the depth in shallow water, thats when I really get concerned about depth, I'm installing 2 furuno vx2 on the flybridge and a display in the cockpit, this will be connected to the black box which can interface with all if we choose, a 1kw airmar 24degree transducer mounted midship strb flush mounted and faired in to minimize white water turbulance, the cockpit is for the crew to interact when trolling and bottom fishing, see the direction of the drift, the speed of the drift and hit MOB when we hookup whether bottom fishing or high speed trolling, we mark structure, bait ,fish and most times retrace our course when there is action, the networked system is for the fishfinder capability and doesnt work well in turbulance when coming into the Boynton inlet and the bar has shifted, my depth sounre is a digital simrad, I have this exact same system on my big boat but have readouts for the sounder and another vx2 on the Marlin tower, been a good system for 2500 hours so far, my son has the navnet system and I cant make it work in the Bahamas or great lakes, not very intuitive, I switched from a 6oo watt to the 1000watt because I wanted to know the depth at 30 knots in 800 to 1000 ' when approaching a suggested fishin hole

Tony Meola · Post by **Tony Meola** » Sep 20th, '10, 20:53

Sim

Believe it or not, We did that in August and did not know it until we pulled the boat for the winter. Scary, but it lasted about 3 months. It is always on my mind now. First thing I always do in the winter when they lift the boat is look at the transducer.

Something you don't ever forget.

Bertramp · Post by **Bertramp** » Sep 21st, '10, 07:05

Marlin ..... the Boynton Inlet is one VERY NASTY chunk of water. I lived in the condos just south and traveled north or south to avoid that set of rapids.

Rawleigh · Post by **Rawleigh** » Sep 21st, '10, 07:51

Like Brew, I have tapers wooden plugs in the drawer under the forward dinette seat right next to my transducers. I hope I never need them, but you never know. This thread really makes flush mount transducers sound better and better!!

Carl · Post by **Carl** » Sep 21st, '10, 09:28

I have dowels as well...but they do little good if your home when the Transducer pops out of the hole.

If I was out or at the boat, yeah I could shove a plug in the hole...provided I find the hole in time. Aside from losing the boat I would hate to traumatize the kids....something about having lots of water slooshing around when your out is a bit unsettling. Been there a few times...pull a hatch and water is right there...yikes.

Never had a Bronze one shear off...either lucky or just did not hit it right..The plastic was only a small clunk...knew I hit something but after a quick check I didn't give another thought. Since then I will give a real good yank on underwater hardware...no more little tug to check.

Tony Meola · Post by **Tony Meola** » Sep 21st, '10, 22:12

Rawleigh

Just tells all of us that strange things happen. Sometimes like in mine and Sims case we get lucky. Otherwise it is Davey Jones's locker for her.

JohnCranston · Post by **JohnCranston** » Sep 21st, '10, 23:24

Brew,
I know your dowels are made out of balsa. What about Rawleigh and Sim.
I feel like a fool for never doing that. The list of stupid things that I've done, or haven't done, is endless.
Thanks.

Rawleigh · Post by **Rawleigh** » Sep 22nd, '10, 08:00

Mine are the tapered wooden plugs that you buy at West Marine or other marine stores.. I never checked what kind of wood they were made of.

coolair · Post by **coolair** » Sep 22nd, '10, 10:28

http://truplug.com/
yall seen these, for i think around 10 bucks look pretty handy, looks just like a oragne safety cone that youcan stick in a hole

In Memory of Vicroy · Post by **In Memory of Vicroy** » Sep 22nd, '10, 13:40

I have a pack of 'em and they look like soft pine.

UV

Carl · Post by **Carl** » Sep 23rd, '10, 07:39

Rawleigh wrote:Mine are the tapered wooden plugs that you buy at West Marine or other marine stores.. I never checked what kind of wood they were made of.

Thats what I have. I have one with the aprox correct proportions near each thru hole plus a few in a storage hatch...in case.

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