Sunday, 28 June 2015

Meade Island to Denham

Hi everyone,
Contrary to our earlier plan we decided to move on to Denham today.  This was partly due to our finding a potential issue with our HF radio, but more on that later.

We are currently anchored at 25 56.0s 113 34.4e in 2.6m (reduced to datum) over weedy sand.  We are about a cable (~200m) N of the first port channel marker which marks the outer end of the dredged channel into Denham.  It is flat calm.  Here is our track from Meade Island...

Zen Again track
We sailed off the anchor at Meade Island in a 4-6 knot SE breeze at 0830 this morning.  We had a slow but very enjoyable sail to the marked channel through the flats N of Cape Bellefin.  We sailed through the channel finding depths as charted on the WA DoT and current Garmin Bluechart G2 charts.  Navionics Gold, CM93 and an older Garmin chart set were less accurate.  Here's some detail from the WA DoT chart (rendered in Memory-Map software).

Zen Again track detail shown on WA DoT charts in Memory-Map
By the way, for those who like raster (vice vector) electronic charts Memory-Map is great value.  All AUS charts and most state charts for under $300.  See their web site here.  The software runs on Windows, iOS and Android (but sadly not Mac OS).

We had to motor through the flats north of Cape Heiresson (on the right above) since wind was then 2-4 knots ESE and we couldn't keep the boat moving.

Approaching first flats
Channel marker
From the second flats we motored the rest of the way.  It was a great opportunity to give the engine a workout.  At our normal cruising revs of 2000rpm we do 5.5knots.  At 2500rpm we do 6.8knots which felt scary-fast after sailing along at 2 knots all morning!  Over 3000rpm we exceed our hull speed a little but burn fuel at a prodigious rate.

Denham outer port mark
We anchored off Denham at 1315 this afternoon after a very pleasant passage.  For a while we watched the world go by and enjoyed 5 bars of mobile signal strength.

Then we did some HF radio tests to try to figure out why we are not being heard when using the radio for voice transmissions.  We have a radio frequency power meter which clamps around the antenna feed, directly measuring transmitted power.  It showed that our antenna tuner needs a lot of signal to trigger its tuning process.  So if my voice isn't _very_ loud the antenna isn't tuned, so the poor signal strength is further degraded by poor tuning.

The solution we came up with was to enlist our recorder (the music instrument kind).  It easily generates a tone which triggers the tuner.  This solves our problem!  The tuner should not need such a high level signal but at least we have a work-around for the issue.  Transmitting DSC messages or other digital formats (eg to send/receive email over HF) isn't a problem since they easily trigger the antenna tuner.

Tomorrow we plan to explore Denham.  We're told there may be a shower we can use.


  1. Hi there,
    I came across your blog and noticed you have a plan to sail across the Indian Ocean and be in Cape Town by Xmas.
    We are currently in Cairns and that is our plan too. Originally hoping to be in Broome for end of August ready to depart to Cocos/Keeling Islands

  2. Are you departing from Broome or further south.
    Danielle and Al
    sv Lets Go

  3. Hi Danielle and Al,
    Thanks for your comments. We expect to clear out from Carnarvon. There is an 'Indian Ocean Crossers' group online - I'll email details of how to join.
    Mike & Nicki.