BY CHUCK HUSICK
techconnection
An MMSI By Any Other Name...
Q. I just purchased a boat with an MMSI number with the
onboard VHF-DSC radio. How do I assign the new information to
that MMSI number? — Herbert Smith
Burgess, VA
A. If the MMSI was obtained from BoatU.S., you can ask the
previous owner to contact BoatU.S. and cancel his MMSI registration. Once that’s accomplished, contact BoatU.S. and ask them to
transfer the MMSI to your name, and supply them all of your registration information. In the event the MMSI was obtained from a
source other than BoatU.S., it may not be possible for the previous
owner to cancel his registration of the MMSI. In this case, you’ll
have to apply for a new number (the easy part) and contact the
manufacturer of the radio or a marine-radio service center to obtain
the unlock code that will allow a new MMSI to be programmed
into the radio. (Obtain a MMSI at www.BoatUS.com/MMSI).
Q. I have both a fixed-mount VHF-DSC radio and a VHF-DSC
handheld radio that I use primarily when on the boat and occasionally when in the dinghy. Will I be able to make a DSC call from
one radio to the other if the radios have identical MMSIs or will I
get a “busy” signal? Is it better to use one MMSI for both radios or
obtain a separate MMSI for the handheld? — James McGinnis
Freehold, NJ
the position of the Loran fix and graphically measure the latitude
and longitude. Or you can use a software program such as Andren
Software ( www.andren.com) to make the desired conversion. I
was able to convert the TDs you furnished to lat-lon coordinates:
A. Radios programmed with identical MMSIs can make DSC
hailing calls to radios that have the same MMSI, and there is no
“busy” signal (unless the called radio has been set to respond as
“busy”). The handheld is primarily used in conjunction with your
boat, so I’d use the same MMSI for both the fixed-mount and
handheld radios so that in the event you need to make a mayday
call, the Coast Guard’s database will show the description of your
primary vessel. If you choose to obtain a separate MMSI for the
handheld, make reference to the description of your primary boat
in the remarks section of the MMSI application form. A description
of the vessel in distress is a substantial aid in a SAR mission.
N28 36.873. W 82 56.190 using a dual mode chartplotter/GPS
(approximate, since there can be variable additional secondary
phase, ASF correction needed for the TDs).
Storing Secret Spots
Q. Like many fishermen, I have a log of favorite fishing spots
whose positions are recorded as Loran-C positions (time differences, TDs). I’d like to convert them to latitude and longitude so
that I can locate and navigate to them using my GPS receiver. Can
the TDs, for example Loran #14337.0 and 45160.0, be converted
to lat-lon? — Robert Guenkel
Brooksville, FL
The Need For Speed
Q. The owner’s manual for the 70-hp Yamaha outboard on
my 16. 2 Wahoo states that the correct operating rpm should be
between 5,000 and 6,000 rpm. I’m getting only 5,100 rpm when
alone in the boat and no more than 4,800-4,900 when waterski-ing. It seems to me that a lower pitch prop will improve acceleration but reduce top speed, a higher pitch prop will provide higher
top speed but slower acceleration. What do you suggest I do to
improve performance? — Rick Kanter
Niantic, CT
A. There are three primary ways in which the Loran TDs can
be converted into lat-lon. Some GPS receivers allow entry of Loran
information and will then display lat-lon. You may be able to locate
a chart that’s overprinted with Loran TD lines, use them to locate
A. The engine speed data you’ve supplied, 5,100 rpm with
one person on board the boat, indicates that the prop is a bit too
large for the boat/motor combination. You’ll obtain improved performance by using a slightly smaller prop that will allow the engine
to reach full rated rpm. However, before you change props, check
the accuracy of the tachometer. It’s not unusual for tachometers
to be in error. With a correct prop, the engine should reach 6,000
rpm with one person aboard the boat and top out at a few hundred
rpm less when skiing.
