Through-hull Depth Transducer used in hull

[Trident]

My new boat has an airmar depth transducer dropped in a plastic pipe that is glassed in to the hull (but with no hull hole) and is then filled with a bit of water - the transducer is the through hull style not the angled in hull style but the previous owner swears it works. I can't test it as the boat is on the hard and of course if I need to replace it or drill through the hull I want to do it before relaunch... So has anyone used or seen this set up and does it work accurately ? Thanks

 

[typhoonNige]

I had a similar setup on my previous boat and it worked fine. I used vegetable oil not water in the tube. It doesn't evaporate away

 

[bedouin]

Are you sure it is water rather than oil?

Loads of boats have this sort of set up - I have one mounted in oil and another external transducer epoxied to the inside of the hull, Both do fine for what I need. There is probably a reduction in the maximum depth they will register - I rarely see readings below 60m - but that has never bothered me.

Might be different if you were talking about high resolution, or forward looking sonar but for basic depth display it should not be an issue

 

[DownWest]

Recently replaced an old Seafarer sounder and transducer with a Nasa combined Depth &Log. The instructions said it fine to put the transducer in a tube sealed to the GRP hull, though they included a plastic fairing if cutting a hole. Resealed the tube with Sikflex and poured in some Johnsons Baby Oil. Works fine.
The problem AIUI is if the hull is cored and damps out the pulses.

 

[Trident]

Great thanks everyone - I shall put some oil in instead of the water and put a screw cap on the top just incase
I had in the back of my head that this was an option but as the previous owner was NOT Mr Maintenance I was kind of doubting everything he said by this point!

 

[Graham376]

The other option is just to bed it on a gob of silicone or epoxy, just make sure no air bubbles in mix.