I'm not certain about the required length, but I know that when Jill wimps
out and puts our outboard engine on the dinghy, it is considered a vessel
under power. I'd think that qualifies it as a 'motor vessel'?

Rudy & Jill Sechez
*BRINEY BUG-a 34' Sail-Assisted Trawler *
850-832-7748
trawlertrainingabc.com http://trawlertrainingabc.com
Daytona  FL

On 12/3/19 4:39 PM, Gary Ritzman via Trawlers-and-Trawlering wrote:

This is another one of those topics like "which anchor is best" or
"single vs. twins." That said, I did a great deal of research on this
very subject before we purchased and named our boat. I did not keep my
notes or references from this once we made our decision, but here is
what I remember of the gist of it:

There are no regulations in the US on this subject. While I found
exactly one legal definition of "Motor Vessel" in the federal code (I no
longer remember exactly where or why), it was not exclusive and had
nothing to do with pleasure craft. So here, on domestic voyages, you are
legally free to use whatever you like.

That said, I did learn that, internationally, there are many countries
where "Motor Vessel" refers strictly to commercial craft and/or vessels
over a certain tonnage. What I discovered when delving into that subject
was that identifying yourself on the radio as a "Motor Vessel" to port
authorities there will cause problems, and that vessels around you will
be confused. The normally accepted term for motor-driven pleasure craft
(with accommodations) of any size below "ship" is "Motor Yacht." When
you hear the big boys, yachts in the 100'-200' range, making radio
calls, this is how they identify. Perhaps something like the 414',
10,000-ton "Octopus" would use, instead, Motor Vessel, because at that
size it is subject to all of the same requirements as commercial vessels
under IMO rules.

We ruminated for a long time on whether "Yacht" (of any stripe) sounded
too pretentious for us; we think of Vector merely as a "boat" (although,
clearly, many we encounter think otherwise). But in the end we decided
that clarity and precision on the radio trumped our squeamishness about
it, and we say "Motor Yacht" on the radio and write "m/y" on forms. Very
rarely, when I actually do want to obfuscate our status as a pleasure
craft ("Vector" is sufficiently obscure to be commercial, and several
commercial vessels can be found using this name), I will say Motor
Vessel or write M/V. (As it happens, we are in a commercial shipyard
right now where we are required to wear hard hats, and I put "M/V
Vector" on them because it makes us stand out less.)

Finally, even here in the US, there are lots of commercial captains,
especially towboat drivers, who will think you are being pretentious if
you use Motor Vessel. To them, an M/V is something over a hundred feet
or so. Personally, I tend to agree, and I chuckle when I hear, say, a 36
footer identify itself as "Motor Vessel So-And-So," and more so if it
has some cutesy name. In much the same way that I shake my head when I
see someone introduce themselves or sign their name as "Captain" when
they are not actually employed in that capacity anywhere.

As a side note to all of this, I often see pleasure craft come up on my
AIS as "m/v Name," "s/v Name," or "s/y Name" (seldom do I see m/y). USCG
and international guidelines for AIS specify that only the name, and not
any sort of prefix that is not part of the official name, should be sent
by the AIS transponder.

-Sean
m/y Vector
on the hard in Bayou La Batre, AL
http://OurOdyssey.BlogSpot.com

Bob:  No disputing right to use owner’s right to nomenclature.  I do note that the definition you site appears to apply soley to Federal regulations applicable to Glacier Bay National Park and Preserve.  I was not able to find anything that expands that definition more broadly.

Personally, I’d have no hesitation referring to your fine ship as the m/y Sanderling.

36 CFR Subpart N - Special Regulations - Glacier Bay National Park and Preserve
CFR 
https://www.law.cornell.edu/cfr/text/36/part-13/subpart-N#tab_default_1
prev https://www.law.cornell.edu/cfr/text/36/part-13/subpart-M |  next https://www.law.cornell.edu/cfr/text/36/part-13/subpart-O
Administrative Provisions (§§ 13.1102 - 13.1109)
§ 13.1102 Definitions. https://www.law.cornell.edu/cfr/text/36/13.1102

§ 13.1102 Definitions.
As used in this subpart:

Bartlett Cove Developed Area means all NPS-administered lands and waters within 1 mile of any Bartlett Cove facility applewebdata://B3F54F53-0919-4933-9152-683BC9EF2376. A map showing the Bartlett Cove Developed Area applewebdata://B3F54F53-0919-4933-9152-683BC9EF2376 is available at the park visitor center.

…

Motor vessel means any vessel applewebdata://B3F54F53-0919-4933-9152-683BC9EF2376, other than a seaplane, propelled or capable of being propelled by machinery (including steam), whether or not such machinery is the principal source of power, except a skiff or tender under tow or carried on board another vessel applewebdata://B3F54F53-0919-4933-9152-683BC9EF2376.