P79 Airmar transducer

[ghostlymoron]

This transducer is 'easily adjustable' to hulls with a rise of up to 22°. How do you install it when you hull is steeper than that - about 45°. Can I just build up under the base unit with filler? Or would that make the hull effectively too thick?

 

[Pete7]

That is a bit tricky because you are going to be firing the signal through quite a bit of GRP at 45' is there anywhere else?

You could ditch the outer ring and just use a piece of drain pipe with one end cut at 45' If you held it in with plasticine and filled it with water it will work just as well as glassing in a tube and give you an insight on how it's going to work.

 

[PaulRainbow]

I'd go with the drainpipe suggestion. If you're happy with how it works stick the pipe permanently with Sikaflex or epoxy, then fill it with antifreeze, baby oil, olive oil etc.

 

[ghostlymoron]

Seems a bit Heath Robinson for an expensive bit of kit. Is there another Airmar sensor that would work?

 

[Mike k]

I have just fitted one and I have a 30 degree rise but am happy with the variation. IIRC the collar that you stick to the floor also ensures a twist fit connection for the transducer so if you go with drain pipe you will need some way of fixing the transducer so it doesn't jump out. I used propylene glycol as the liquid and so if you are using drain pipe just ensure that you have enough to cover the face of the tranny.

 

[PaulRainbow]

Seems a bit Heath Robinson for an expensive bit of kit. Is there another Airmar sensor that would work?

People have been fitting them in pieces of pipe, tupperware pots and allsorts for yonks

Find a suitable piece of pipe, a bit larger diameter to the transducer base. Shape one end to fit the hull, as best you can. Slit it lengthways and tape the slit up. Stick it to you hull with some plasticine. Pour some slow drying epoxy into it to reduce (or eliminate) the deadrise. Once the epoxy has dried, remove the pipe and plasticine and fit as normal.

You can use propylene glycol to fill it, as Mike said. That's the current Airmar recommendation. It's what's commonly know as "food grade antifreeze". Supposedly environmentally friendly. Many people fill them with normal antifreeze (used to be recommended at one time) or thin oil.

 

[ghostlymoron]

It's a pity Airmar don't do a 45° version. That would be a lot neater.

 

[Neil]

I 'moulded' a circular ring (with one side higher than the other) by hand from epoxy filler to accommodate the extra slope. Filed the top of the filler ring flat then put on Airmar's ring that you can rotate to get the transducer flat, with silicone. Filled with baby oil.

 

[ghostlymoron]

I 'moulded' a circular ring (with one side higher than the other) by hand from epoxy filler to accommodate the extra slope. Filed the top of the filler ring flat then put on Airmar's ring that you can rotate to get the transducer flat, with silicone. Filled with baby oil.

That's the best suggestion yet but i still feel that a finely engineered piece of kit like the airmar shouldntnhave to sit atop a hand moulded adapter or a piece of drain pipe.
Question for Neil. How much oil did you use?

 

[PaulRainbow]

That's the best suggestion yet but i still feel that a finely engineered piece of kit like the airmar shouldntnhave to sit atop a hand moulded adapter or a piece of drain pipe.
Question for Neil. How much oil did you use?

If you followed my suggestion you don't have to do all the filing and shaping, the epoxy mold itself to the hull and the surface self levels.

 

[salar]

Very simple solution. Cut the base flange off the vertical tube. Find or make a tube that the original vertical tube will fit inside. Cut a 45% angle on the other end of the new tube. Bond to the hull so it is vertical. Strengthen with a fillet where the new tube meets the hull. Bond or seal the two tubes together. That way you have the original top mounting and an adapted lower and it will perform as well.