Jump to content

Transom Mounted Transducer


charlieannear
 Share

Recommended Posts

Can anyone offer me some assistance in fitting the above to my boat, please?

 

The drilling of holes etc isn't the problem- what I need is some advice as to where to locate the transducer so that it works properly.

 

If it makes any difference, it's a Navman transducer, and I'm wanting to fit it to a Shetland Family Four.

 

Thanks (Hopefully!)

 

C.

Link to comment
Share on other sites

Charlie

 

You will obviously have to fit the transducer off centre and away from the engine. The transducer needs clean water and by that I mean no air bubbles in the water or other turbulence. Look under the boat and see if any bits stick out of the hull that could cause turbulence. The cleanest area forward of your proposed transducer location will give the best trouble free picture

 

If you would like me to pop up just shout

 

Martin

Link to comment
Share on other sites

Echo Martin

 

And happy to pop over if it will help.

 

Typically, looking at the transom from behind the boat the transducer will be fitted a foot to 2 feet away from the centre line (well clear of the swing of the prop) and as Martin say's, clear of anything that may cause an obstruction in water flow such as a chine, skin fitting etc.

The transducer is fitted marginally lower (just the flat bottom of the transducer) than the hull and normally faces forward by about 5 degrees. This should all be in the installation guide for the transducer.

 

Happy to help by taking a peak if it will be handy.

 

Tom

Link to comment
Share on other sites

Echo all of the above PARTICULARLY the 5deg forward inclination. this ensures that there are no little air bubbles caught up in the vortex of a wrongly inclined transducer.

 

Secondly remember that the transducer needs to be fixed horizontaly to the WATERLINE and not follow the angle of the slight V at the rear of your boat.

 

If you follow the hull line the transducer will 'look' at that angle and in say 60ft of water what you see on the sounder screen will be about 10ft to one side of you.

 

Help here too if you want it and I also have plenty of teak offcuts and a home workshop to cut a 5deg wedge for you in about 2 minutes or 3 min' if you want it varnished as well biggrin.gif

 

Oh and t'other thing use a silicone sealant to bed it down on.

 

Mad Mike

Link to comment
Share on other sites

Thanks guys.

 

The installation manual is pretty specific about depth below the waterline and angles of dangle etc...

I've got a tube of sikaflex ready to go and drill all charged up...

 

My problem is that not having had the boat in the water I'm not sure where the waterline is! laugh.gif

 

Also because the Shetland hull is a bit 'gul-wing' I'm not sure how far away from the motor I can go before the transducer would effectively be mounted too high.

Conversely, not being terribly well versed in this lark yet, I'm not sure how close I can get away with having it to the motor.

 

If anyone fancies popping in for a cup of tea/cold squash and suggestions as to where I should drill my holes, I'll be in all day Thursday! cool.gif

 

Perhaps you could all visit, I'll mark where each of you suggest and we'll see to what extent you agree? tongue.gif

 

I have comfy patio chairs and parasol for those waiting their turn at pinning the 'ducer on the Shetland. Choccy biccy for the winner! laugh.gif

 

C.

Link to comment
Share on other sites

Hi Charlie

 

Don't fit it just below the waterline, it needs to be under the water about .5cm beneath the transom itself. Add at least a foot to the widest swing of the outboard propeller and that will avoid aeration from that.

When on the plane, the transducer needs to be underwater still and in "freewater" (ie not full of bubbles from the prop or tucked up behind the transom).

 

Tom

Link to comment
Share on other sites

Thanks again Tom

 

Does this mean you're dropping out of the pin the 'ducer on the Shetland game? Has Mike frightened you off?

Glass of cold squash still on offer if you fancy it! wink.gif

 

C.

Not frightened of Mike ohmy.gif Well not about transducers anyway! He scares the sh1t out of me normally ohmy.gif .

 

To be honest, I could fit a transducer with my eyes closed...oh yeah that is the same as "Pin the 'ducer on a Shetland"! tongue.gif

 

If I get the chance I'll pop round, I need to pop out some time today for a baseball bat, a tough bucket and some balloons blink.gif, the thought of a cold squash doesn't quite do it for me, but I may come and say Hi.

Link to comment
Share on other sites

for a baseball bat

 

Tom if you need I could lend you one, an origional one as used by The New York Yankees back in the 80's

 

Mad Mike

 

PS re: To be honest, I could fit a transducer with my eyes closed...oh yeah that is the same as "Pin the 'ducer on a Shetland"!

 

Having seen the way some transducers are fitted I would guess that you've fitted a few with your eyes closed tongue.giflaugh.giflaugh.gif

Link to comment
Share on other sites

Charlie,

I have twice fixed a transducer internally, mounted on a moulded block of plasticine. Perfect reception/display, accuracy checked with plumb line etc.

 

The last one was for a fish finder in my previous boat, despite the manufacturer recommending drilling through. It lasted the 4 years between installation and selling the boat.

 

If the device is portable, and can be easily connected to a battery - might you be able to test it out before drilling, even if you have to "borrow" a boat to see? I would offer, but am away on business this week.

 

Mind, it was never subjected to the speeds you'll be experiencing!

 

Mike

Link to comment
Share on other sites

Thanks again Tom

 

Does this mean you're dropping out of the pin the 'ducer on the Shetland game?  Has Mike frightened you off?

Glass of cold squash still on offer if you fancy it!  wink.gif

 

C.

Not frightened of Mike ohmy.gif Well not about transducers anyway! He scares the sh1t out of me normally ohmy.gif .

 

To be honest, I could fit a transducer with my eyes closed...oh yeah that is the same as "Pin the 'ducer on a Shetland"! tongue.gif

 

If I get the chance I'll pop round, I need to pop out some time today for a baseball bat, a tough bucket and some balloons blink.gif, the thought of a cold squash doesn't quite do it for me, but I may come and say Hi.

Hope you didn't make a wasted trip today Tom, it's Thursday I'm at home all day.

 

I've got cold cans of funny tasting squash with Stella on the label if you prefer!

Link to comment
Share on other sites

Charlie,

I have twice fixed a transducer internally, mounted on a moulded block of plasticine. Perfect reception/display, accuracy checked with plumb line etc.

 

The last one was for a fish finder in my previous boat, despite the manufacturer recommending drilling through. It lasted the 4 years between installation and selling the boat.

 

If the device is portable, and can be easily connected to a battery - might you be able to test it out before drilling, even if you have to "borrow" a boat to see? I would offer, but am away on business this week.

 

Mind, it was never subjected to the speeds you'll be experiencing!

 

Mike

Hi Mike, the transducer I have needs to be transom mounted otherwise not sure how the paddle wheel on it will work through the hull... wink.gif

Link to comment
Share on other sites

ooh, very clever......lol

 

when i hit 8knots the screen will flash, and the depth reading will freeze. When I slow down again, the normal reading will resume. Im guessing bubbly water is the problem so I want someone with more of an idea about 'mounting' than me.

The problem you describe sounds like the return signal to the transducer is not being recieved as the boat has traveled too far forward from the 'send' point to read it. This was a common problem of the very early depth sounders. The freezing of the depth signal will be the readouts default of the last known depth.

You slow down and then the return signal does have time to get back to be 'heard' by receiving bit of the transducer and the diplay starts up again.

 

If the unit is a modern one then something is very wrong and I don't think it will be transducer position. The signal sent out by the transducer is a wide angle beam not a tight one, therefore unless you are going super fast (50knts+) or in extremely deep water (600ft+) the boat should normaly be within the returns footprint.

 

Now as I type this the thought occurs to me ....... Do you have the flat underneath part of the transducer angled forward a lot (more than 5 deg) ? If so that could cause the problem.

 

WHere is the boat ? I could come and have a look ?

 

Mad Mike

Link to comment
Share on other sites

  • 5 weeks later...

Oh dear! Looks much too close to the trim tab............................................................................................................................................Only joking!

 

Terry.

Edited by plaicemat
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...