Pat Morgan
2024-02-18T21:51:50Z
I am looking to get a new depth sounder for my Parker 31. The existing (original) Stowe instrument is not working well.

I don't see any readily available item which will go in the existing through-hull hole. The choice seems to be a simple NASA instrument (the display part will fit in the space on the instrument housing) or something from Raymarine which will cost hundreds of pounds more. It seems that with the NASA one I would need to mount the transponder inside the boat and it is supposed to work properly through the hull.

Has anyone fitted such a thing to a P31 or got any useful advice about mounting the transducer inside the boat? Thanks.
2024-02-26T21:52:48Z
Pat
I replaced mine a couple of years ago with the NASA unit, a more economical option. The display fitted existing cut out no problem. With regard to the transponder, it was fitted inside and works well. Replaced the speed unit at the same time , as both units displays were increasingly difficult to read.

Hope it helps

Chris
Christopher Day
P31/5 Sula
Pat Morgan
2024-02-26T22:05:38Z
Thanks Chris.
I was hoping it was going to be straightforward. I will go ahead with the NASA instrument.
Pat
Pat Morgan
2024-03-01T19:38:17Z
Chris,
Did you use the "In Hull Transducer Mounting Kit" which you can buy as an extra? Or did you bed it in mastic or what? I gather there must be no air bubbles between the transducer and the hull.
Thanks, Pat
2024-03-01T22:25:02Z
Pat
It was done by Upson’s yard, as they replaced the speed log unit as same time, as removing the old log unit’s through hull fitting kit and cutting new holes in the hull is a job I leave to the professionals!

A mounting kit was used, I have a feeling they put oil in the tube for the transducer to sit in, I would go and check but have just arrived in Caribbean for a couple of weeks.

Hope this helps

Chris
Christopher Day
P31/5 Sula
2026-07-23T10:04:04Z
Hi,

I'm just tagging along on this post to keep everything in one place.

I've recently bought a Parker 21, which I'm keeping on a mud swinging mooring on Chichester Harbour, that has no working electrics. I bought along a motorbike battery to test things but nothing appears to work bar the VHF radio (although I have no antenna). My main priority is getting a solar panel to keep the motorbike battery charged and to sort out the depth sounder that doesn't appear to work. I was wondering if the transponder can be replaced from the inside (once dried out on the beach) or if it needs to replaced from the outside-in..

Also. from these images can anyone tell me which is the transponder and which is the log?
WhatsApp Image 2026-07-23 at 10.40.46.jpeg

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WhatsApp Image 2026-07-23 at 10.40.46 (4).jpeg

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WhatsApp Image 2026-07-23 at 10.40.46 (1).jpeg

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As for the solar panel, there is a pre-existing panel that has been disconnected and there is no controller. Would any type of controller do and do I just connect the controller direct to the battery. Or is it better ripping it all out and starting with something like this? https://uk.renogy.com/products/200w-12v-flexible-solar-marine-kit-w-20a-voyager-waterproof-charge-controller 

Any help/advice would be much appreciated.

Many thanks
Manuel (Galadriel)