Nothing is worse than realizing that you lack depth. Especially when you have your life savings invested in a sailboat that you’re living on with your family, and your depth sounder suddenly stops working. Even worse is if you’re in an area that the charts mark as “shoals”. “Shoals” is shorthand for: the sand on the bottom in these parts moves around a lot, so we can’t tell you what the depth is at any given moment. Have a nice day!
That’s why you have a depth sounder. Ours in particular has been wiley at best. When we first moved aboard, we realized that it wasn’t logging the boat speed. Most do. Ours doesn’t. It’s not broken, it’s just not a feature. We learned to live with that, and got our boat speed from other sources. It also, when working, reports the depth 2 feet shallower than it actually is. How did we figure that out? Easy, our first day on board we hit ground when the gauge said 2.5 feet. Our boat is 4.5 feet deep, so that must mean a 2 ft offset that we need to calculate on the fly. Or, we could calibrate it. It’s on the list.
Bottom growth (little nasties growing on the bottom of the boat) also affects the depth sounder, requiring regular cleaning. Failure to do this results in some erratic results. That is super fun when you’re trying to anchor and it tells you that the water is thirty feet deep when it’s ten. Or it says twenty and you’re hitting bottom. Both have happened. Why is it important to know the depth when anchoring? Well, not only do you not want to hit the bottom (obvious), but you need to know the depth to decide how much chain to put out. That keeps you from dragging anchor, which in turn keeps your boat from crashing ashore and being pounded to little bits in the surf.
All of the above items are just everyday fun that every boater deals with, but this time it just stopped working. Instead of showing us numbers for the depth, it constantly displayed “–”. Not ideal. I immediately ordered a new depth sounder on Amazon, to be delivered the day before we were scheduled to head out on an overnight passage. I could just swap it out really quick once it arrived and we’d be good to go. Then, of course, the package got delayed. It was now set to deliver the night before we left. That’s cutting it close. But, luckily, it was delivered at 9pm as promised. Hurray! Except that the marina office was closed at 9, and we had no idea where in the complex it actually got dropped off.
No worries, luckily Hunter ended up in the ER, so we didn’t have to leave the next day. Did I just say that? I by no means mean that it was lucky that he was in the ER. It was lucky that we didn’t have to leave, because it took all day for them to track down the package. When I finally got my cherished brown smiling box, I was ready to open it up and get installing. Hmm. This doesn’t look right. Where’s the sensor? Whoops…they forgot to include it. After a pretty quick interchange with Amazon Customer service, a new one was on the way…and it would be here in three days. Looks like we’re going to be waiting at the marina for a while waiting for the new new depth sounder.
“New”. That word should have tipped me off. They change the standard way of building boats every year, and most builders don’t follow any standard. That means that the older your boat is, the less likely that off the shelf parts are going to just work. This is nowhere more true than with boat electronics. Depth sounders are electronics. What’s worse is that they are electronics that plug into other electronics.
When the right unit finally arrived, I realized quickly that I was about to try to fit a square hole into a round peg. The sounder was top of the line, which meant that it didn’t plug into our 5 year old chart plotter that had been adapted to work on our 15 year old boat. I hadn’t ordered the adapter. I tried for hours to unplug and move around various components behind the chart plotter to get an open port to plug into. No luck. What’s worse was that I had to take down the kitchen cabinets to get to the back of the plotter.
This wasn’t even supposed to be the hard part. This was just testing the wiring. I still had to take the old depth sounder out and install the new one into the boat. No biggie, right? Wrong. Depth sounders get installed into thru hulls, which are exactly what the name suggests. They are a big 2 inch wide hole through the hull of your boat. You would ideally swap out something in a thru hull while out of the water so that you don’t sink the boat. We don’t live in the ideal world, so I was going to try a trick that our instructor captains showed me.
Step 1: get a big thru hull plug and a large mallet.
Step 2: start to unscrew the old depth sounder, with somebody standing by with the mallet and plug
Step 3: As soon as the piece is free and a spout of water starts rushing into the boat, jam the plug in the hole and start pounding with the mallet.
Step 4: Take a deep breath, and then do the steps in reverse with the new depth sounder. Hoping the whole time that they didn’t change the size in the last 15 years, which they probably did, making the whole exercise moot.
I was not looking forward to this.
Oh well, back to the wiring. Google was no help. Why? Because there just happened to not have been anybody who recently tried to port an Airmar 810 into a C470 Fishfinder that interfaces with a Raymarine eS series via NMEA 2000 adapted to RayTalk. Weird. Looks like I have to try to piece together a solution from bits of various posts.
One in particular caught my eye. Did you try to reset the sonar? Um, no. You can reset the sonar? Is that the same as the depth sounder? Yes you can. Yes it is. Of course there are no instructions on how to do this, so I start fiddling with the various settings on the chart plotter. Eventually I found something that looked close, and took a shot. I had to select my depth sounder type from a drop down list. Not knowing what the old one was exactly, I picked the most interesting sounding name from the list and held my breath.
The result? After being without depth for weeks. After waiting for the new depth sounder to arrive from Amazon (twice). After spending a day scratching my head trying to figure out the electrical connection and fretting the thru hull. After Mere had to take the kids for a walk so that they wouldn’t hear my cussing. After all of that…the solution was basically that I needed to reboot and the depth sounder magically started working again.
Sigh. At least I got my money back from Amazon.