Friday, February 21, 2014

Busy, busy, busy in Seattle

Its hard to believe another week has gone by and we’ve only got a week left here.  Time flies when you are working on a boat I guess.


That’s the view on the famous sonar that I wrote about last week.  It has consumed a lot of my time and attention for the past week.  You have to have a good imagination to interpret the screen image but on the off chance that someone is interested, here’s what you are looking at.  Bear in mind that I have a LOT to learn so there is likely much that I am missing.  It also helps that I can clearly see the world around me and use that information to interpret what I am seeing on the sonar screen.  If you are going to try to follow this explanation it will probably help to enlarge the image and keep it handy while you read on.

The scan is set to 180 degrees – we can set it anywhere from roughly a 10 or 15 degree wedge to a 360 degree full circle and then we can turn the dome to point it forward, backward, sideways or anywhere in between.  The four squiggly red blobs in the top half of the blue semi-circle are the keels of the four vessels in front of us.  In the upper left corner you can see that the beam is set to zero degrees which means it is looking horizontally forward from a position about 4.5 feet below the waterline (our deepest draft).  The relatively heavy red line though the centre of the image is the floating dock.  We could use the cursor to measure how deep it is but that is too difficult to show – you’ll have to take my word for it being about 5’ below the water level. 

The big challenge this week was getting the display to reliably light up when I turned it on.  That turned out to be as simple as building a new coax cable to hook the display up to the control box.  The coax that came with the boat looked good which was what kept me trying to make it work for so long – it was a professionally made cable with two BNC male connectors and then a BNC to RCA adapter.  I think the adapter was actually bad – it worked a lot of the time but whenever I turned the sonar on it was always a crap shoot as to whether anything was going to appear on the display.  Having bought the display used from unknown sources I was more disposed to blame it than an apparently good (and incredibly simple) short piece of coax but eventually I rode the bus to Radio Scrap and got me some new BNC and RCA cable ends.  I had some coax onboard from when we replaced radios so it didn’t take long to build a new cable and the display has worked flawlessly ever since.


That’s our new-to-us Garmin radome.  It came from some dude in Maine who had it advertised on  I agonized over whether I should buy it and then worried myself silly about how to hook it up.  In theory I can display its output on our open source chartplotting software.  Ultimately I just couldn’t convince myself that system would be an adequate redundant radar system.  The whole point of adding a second radar is to have a second radar.  Actually to have a primary radar that is more current technology than the 30+ year old system we currently use.  This radome is only 3 years old and supposed to be in like new condition – it certainly looks to be good. 

After the radome arrived I initially thought I could convince myself to just use the radome and display it directly in OpenCPN but ultimately I talked myself out of that plan.  According to the USPS tracking system I have a Garmin 3010 chartplotter arriving tomorrow from somewhere in Florida.  That chartplotter could be up to 10 years old but it is supposed to be in working condition.  Assuming it all works, it will give us complete redundancy in both our charting and radar systems.  The Garmin system will be entirely separate from the system that we currently use other than that it will be capable of driving the autopilot and outputting position information to the radio.  We’re pretty well out of space around the helm so I’ll have to either stop buying instrumentation or start removing old instruments before I add new ones.

The yellow hose underneath the radome in the picture is Van’s hookah system which he very generously gave us last weekend after Nancy fed us an incredible meal.  I told him he should keep it in case they buy another boat but he said that was unlikely and if they do he still has all his free diving equipment.  “Hookah” for those of you who don’t know, just means air supplied diving equipment that isn’t self contained – ie. the air comes down a hose from the surface.  Most often Hookahs will have a compressor on the surface supplying the air but we won’t go that far.  We’ll just carry a couple of air tanks and keep them full.  All we need is enough air to clear the prop when our idiot captain fouls the prop on a line.  And perhaps enough air for the same idiot captain to check zincs or even replace a zinc away from the Cow Bay dock.  As long as Terry-the-diver is willing to clean the bottom and change the zincs for $100 we’ll keep using him but he doesn’t make housecalls to Desolation Sound.  Or even to Victoria as we discovered last spring.

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