Sunday, June 11, 2017

Marine Tech Tango

Just a pretty picture (totally unrelated to the post) to remind us why we're working so hard this summer.

And so it came to pass that a person of some means bought a new-to-them sport fishing / trawler / live aboard boat. It wasn't a new boat, but at 48 feet long, equipped with two huge engines, and with an interior that would do justice to a 4 star hotel, no one would consider it a bargain boat either. Being of the budget cruiser tribe I would not normally get very close to such a boat, maybe see it motor by an anchorage as it made for a dock somewhere in the islands. However, we are filling the cruising kitty by having me do the marine mechanical tango this season, which is how this particular trawler and I became dance partners.

Aircraft are required, by law, to be regularly inspected. Virtually all inoperative items, no matter how minor, must be repaired before it can return to the sky. There are no such requirements for boats, and my experience is that they decay slowly. Inoperative systems get fudged, hacked, Micky Moused, or just left not working if there isn't a real chance that the failure will put the boat on the bottom. That is, right up until the boat gets sold. Then, all of a sudden, items that haven't worked in years have to be repaired. Sometimes that happens before the sale is complete. Sometimes, after appropriate price concessions by the seller, the new owner hands us the work list.

This trawler has a list a few pages long; not the least bit unusual. Tucked away in that list was a simple “spot light not working” complaint. Spotlights are not particularly complicated systems, even the ones that are supposed to tilt and swing on command from the helm. But the marine industry has an aversion to wiring diagrams, so troubleshooting is mostly shooting in the dark. Starting out, I didn't even know how many components made up the entire system. The remote switch was obvious, as was the light mounted to the bow. Wiring between them could be assumed, along with a power supply protected by a fuse or breaker. And so the music started and the dance began.

“Spot light not working” didn't actually mean the light wasn't working. What it likely meant was that the new owner didn't know there was a fold away breaker panel in the helm were the light got its power. I suspect that because that same panel has a breaker for the horn and, though “horn not working” was also on the list, the horn worked just fine once the breaker was closed. In like manor the light came on when the breaker was closed. Which is wrong. The light isn't supposed to come on with the breaker. It is supposed to be controlled by the remote switch.

General consensus was that the remote switch is a weak link in these systems, rarely lasting more than a couple of years. A new one was ordered and installed. Nothing. Damn. But the paperwork with the new remote mentioned a “master control”. Hmmm, wonder what that is and where it is located? As it turns out it is located in the anchor locker and when I found it, the reason the remote switch didn't work while the light came on with the breaker was clear. Someone had butchered the wiring harness, jumping the master control with hot and ground wires twisted together and secured(?) with rigging tape.

The general consensus was that the master control had failed, rendering the light inoperative, and was thus hacked out of the system so the light would at least shine when requested. A new master control was order and installed. (No mean feat tucked into the anchor locker.) Nothing. Damn.

There is a single run of coax cable connecting the remote to the master control. This was a puzzle. Coax is, basically, an antenna wire wrapped in an insulating sleeve, surrounded by a wire mesh to protect it from stray radio waves, (called a shield) with the whole thing wrapped like any normal wire. Coax cables carry information, not power. But the remote clearly needs power to function, so...from whence comes the electrons to light up the remote? Oh for a single glance at a wiring schematic!

Wanting to make any kind of progress I tested the coax. The center wire checked good, but the shield? Somewhere in the nearly 100 feet of cable run the shield was broken. Could it be that they are using the shield to carry power from the master control to the remote? I ran across a similar thing last year, working on a boat's navigation system. So, on a lark, I jumped the shield with a run of wire from the anchor locker, across the deck, up onto the flying bridge, and behind the helm. The remote lights and clicks just like it should. The spotlight goes on and off with the touch of a button. But it still doesn't pitch or swing.

Damn.

So it appears that, somewhere in the distant past, the shield failed rendering the entire system kaput. It was hacked to make the light work, damaging the master controller in the process. I have no idea how long ago this happened, though the butcher job appears old, with tape brittle, wires corroded, and hanging bits filthy. A good guess is that the extended time with the motor inactive has rendered it inoperative as well. (New – and expensive – searchlight systems automatically exercise the motor / gear box on a regular basis, without any input from the crew. Pretty cool, that.)

But the primary problem remains that of the open shield wire. Running a new coax is the only fix and, as usual, there is no documentation as to where the wire chases run through the boat. The only option is to make the best guess possible and start taking the interior apart. Removing the back of the master berth hanging locker pointed in the right direction, but wasn't where I needed to be. Where I needed to be was behind the starboard settee in the cabin, forward of the main DC / AC distribution panel. (Located, by the way, behind the TV. Which ranks up there as one of the dumbest things I have seen on a boat.) So, lift the cushions off, right?

Right. No amount of effort would get the back cushions free. Cushions covered with expensive looking leather. Leather that cannot be damaged lest the new owner become a very unhappy person. I like to think I'm pretty good at this stuff but, for the life of me, I could not see what was holding the things in place. Swallowing my pride I went to Boss not-so-new and admitted my ineptness at interior removal. He sent me some help and, between the two of us we couldn't figure it out. Help got called away to do a sea trial on an autopilot, and I went back to scratching my bald head. An hour or so later (try not to think of the labor costs) he returned. Not long after we stumbled upon the problem. The builder of this boat had cut tiny holes in the leather seams, inserted a screw and screw driver, jammed the screw through the foam and batting, and screwed the cushions semi-permanently to the structure. Getting them off required sticking a screwdriver though the leather, fishing around to find the hidden screw, and backing it out without stripping the head off the screw or tearing out  the seam or the leather. Then do that 7 more times.

There are other places we need to be as well. Down in the hole that is the anchor locker. Down in the hole under the starboard side settee up on the flying bridge. In the hole that is the crawl space behind the helm.

Even though most of the wiring run was mapped out by quitting time Friday, actually feeding the wire will take a major effort on the part of two of us at least. It will be hot, ugly, dirty work crawling into the nastiest places on the boat; and it will take hours. But there are two things I am pretty sure will happen. The first is that we will eventually figure out something and make it work. The second is that, someone, somewhere, is going to complain about how long it took and how much it cost.

The marine tech tango.

ps: just for those who are curious here are some of the other items found while working on the list...

Two of the three bilge pumps were inop.
The mecerator pump for the fish box under the cockpit was inop.
The wash down pump needed replaced. It worked, but there were pieces falling off of it.
The pump for the live bait well was just hanging by its wires, one of which pulled free, and was inop.
One of the three depth gauges was inop, along with the knot log.
Two of the deck drains in the cockpit were broken free.
The valves for the "crash pump" option of the engine water pumps were frozen.
The head overboard thru-hull / valve was letting sewage leak out and sea water leak in.
There are contractors taking big pieces off the engines; I have no idea what that is about but it looks expensive.
The underwater lights under the swim platform were inop, at something on the far side of $400 to replace. One must crawl down in the hole in the cockpit to wire them, but I was already in that hole for bilge, mecerator, and fish tank pump repair. Repairing the forward bilge required crawling into the hole under the v-berth and up against the holding tank. While down in that hole I found the wiring for the gray water tanks had been butchered.

It is enough to make one question the wisdom of being on any boat that is further away from the shore than one can easily swim.

5 comments:

S/V Veranda said...

Bet you're glad its not your boat :)

G4DYR said...

That trawler sounds like my fishing boat when I bought it. [Pursuit 33 Express]
BUT it had lived on a lift at the bottom of the owners yard for 8 years and the inside had never been used so it was immaculate.
I bought it real cheap and as an engineer was able to correct a sever engine vibration, failed pumps and lights not working.
Here is the work I did to get it ready for slow trolling on Lake Erie:-
http://www.g4dyr.com/pursuitmods.html

I miss sailing the Hunter 34 but love being able to fish with the Admiral.

You pair are very good at documenting your travels and the work you do to keep blogging.
You should also have a YouTube channel.
This is the way Sue and I blog, purely with a video camera.

http://www.YouTube.com/g4dyr

Thanks for keeping your blog with almost daily news and events.

Cheers

Roy Page
Beloit OH

Dennis D said...

I am an industrial electrician, and used to work on aircraft comms and radar. here is a cool tool that has come way down in price, and would have probably paid for itself during a day like you described.
http://us.megger.com/hand-held-time-domain-reflectometer/cable-length-meter-tdr900
Fluke also makes these, I just googled a link to show you what I was talking about. On any pair of wires, they can tell you the length (approximately) to a short or open. Some industrial electronic rental places have them if you want to try before you buy. Not sure if you ever heard of them before, but it sends a radar like pulse down the wires and times the reflected energy coming back from a change in impedance (shorts, opens, crushed coax). In your example, if you knew where the fault was, you could have gone to that location and fixed it directly, instead of ripping the boat apart to run fresh cable.

Ben Tudor said...

What an amazing story. Troubleshooting can be fascinating but not in 75 degree dew points. A great post. Well written

Tod Germanica said...

Sounds like you'll always have job security so long as boat entropy exists. Funny scary post.