As a cruiser with 42k miles under my keel
, I don't hastily install equipment
on my boat. I like to plan for installations and take the time to research
options before jumping for the first lowest cost option I can find.
I understand that these units contain the GPS, but you also need to plan for the location of the antenna and a high quality unit would require an antenna and that antenna wire would need to fed through my radar arch
and that's not a particularly easy thing to do, spur of the moment. And of course, if done right, would probably also require dome SS welding for a secure and proper mount.
Same situation exists with the VHF antenna. My current
receiver is an Icom
black box that has an internal antenna splitter and is connected to the computer for use by OpenCPN
. When I eventually move to a transceiver, I will opt for a separate VHF antenna for the unit. Again, further complicating the installation.
I'll wait and do a proper installation of a high quality unit before I get forced into a hasty installation to comply with a knee jerk regulation passed on a whim by a particular jurisdiction that may not even be in effect come January when I planned to visit. It would be a shame not to be able to return to Thailand this year, but in the meantime they might find a way to have portable cell phone
units for rent that will satisfy the requirements similar to what Singapore
And your right about being able to program the units to minimize the number of alarms they send. I think OpenCPN
has, hands down, the best implementation of AIS of any receiver I've ever seen. When I transited the Singapore
Straits a couple of months ago, OpenCPN detected over 800 targets. I had things set to only issue an alarm
if a target was going to be within 1/4 mile within 5 minutes. In an area that congested, you don't need to be getting an alarm
for a vessel 10 miles away who will be within 2 miles of you in 30 minutes. Set like that the whole screen
would turn red!
Had an interesting experience about 6 months ago when coming down the west coast
of Malaysia. We were transiting inside Klang harbor when an AIS distress
signal went off about 3 miles from our position. It was a real distress
signal also accompanied by a DSC
signal. A short time later and SAR aircraft target appeared on the screen
and was overflying the area. We had never seen that before. The alarm and distress signal went on for hours and hours. OpenCPN kept identifying the alarm and I suspect all other AIS units were doing the same.
After a few hours of this, I noticed I had far fewer targets on the AIS. And I mean far fewer! I noticed I was no longer picking up commercial shipping
vessels at anchor
that were there just a few minutes earlier. In fact, even though there were hundreds of ships in the area, I was only picking up 30 or 40 targets. At first I thought there was something wrong with my receiver. Then I realized that the guys in the wheelhouse probably got sick and tired of listening to non-stop alarms going off and simply turned their AIS units off!
I captured a screen print of OpenCPN with the distress signal and the AIS aircraft target that overflew the area. I've included it here. You can see the aircraft near the mouth of the river. Was also going to upload a screenshot of Singapore Straits with 874 targets but it's too big to upload.