This job also was not done today but over the last week.
The old "Clipper Sounder" had it's transducer come loose from the resin holding it to the hull which was directly below the head unit. So the readings I was getting were history as it was located behind the keel.
What you are looking for is a bit of future with your sounder by having your transducer fitted well forward in the hull.
The "Clipper" is replaced by a Garmin echo 150, which at $89 from Tackle World I thought was quite a bargain. It is only monochrome but it has dual frequency, alarms and is configurable to read feet, fathoms or metres. The fish find capability is a bonus.
There was a box of sorts over this and the bulkhead and most of the rest of the yacht had been lined with 3 mm particle board with a matte white finish. The previous owner went to a huge amount of trouble cutting it to size and shape and then glueing it in with liquid nails but buggered it up by using cheap material.
I have removed most of it and I am going to paint the glass with gloss white enamel. The VDO Sumlog is a museum piece and it is replaced with a Garmin GPS Map 72H which though it is their basic unit, it is accurate and has a map plot page. It used in conjunction with Navionics on my 9" tablet should serve my purposes cruising the Queensland coast quite adequately.
I am not going to cut anymore holes and wanted to make best use of the existing holes so I shaped up a piece of meranti from the shed to attach the new instruments to.
Notice the dome nuts on the end of the bolts fitted so that there is nothing sharp to get snagged on.
The halyard and lines bag had to be moved up a couple of inches to prevent fouling on the instruments. I did not use the swivel base for the sounder and flush mounted it to keep the plugs and sockets out of the weather. I bought the weather cover for the sounder also.
I haven't used the swivel part of the GPS mount. The power lead for the GPS is taken through the companionway and it and the GPS are taken inside when not in use so as to keep that socket out of the weather too.
You will see the temperature reading under the depth reading. As the transducer (transom mount type) is mounted inside the hull I won't get an accurate reading of water temperature but hopefully it will be sensitive enough to register changes in water temperature.
The location for the transducer had some loose and flakey paint on it so I gave it a scrape and a bit of sanding. The silicon used is Selleys neutral cure Roof and Gutter Sealant ($8) and was applied with half the nozzle cut off to give a 10 mm bead. It needs to be applied carefully so that there are no air bubbles trapped into it.
I wanted to get it as far forward as possible but also out of the way from getting knocked around. Therefore I placed just behind the main part of the locker under the forward berth.
The 6 metre cable was long enough to reach the head unit but only directly through the main cabin. I will be routing it through the lockers on the starboard side for which purpose I bought the 3 metre extension cable ($40, ouch). Today I bought a 100 pack of stick on cable mounts and zip ties ($26, ouch again) to complete the job. Overall I am really chuffed with the new gear being on the boat.