[Hud3]

It is not accurate to compare the search powers of the U.S. Coast Guard (military authority) to those of peace officers (civil authority). The Coast Guard, by federal statute, has much broader authority.

Here's an interesting discussion on the topic by attorney John Wallner:

Reference: Live Aboard 9605: My Boat Is My Castle: The 4th Amendment at Sea

"Ever since 1946, the Coast Guard has enjoyed wide search powers on
'all navigable waters' under U.S. jurisdiction.
The current text of 14 USCA s 89(a), states:

The Coast Guard may make inquiries, examinations, inspections,
searches, seizures, and arrests upon the high seas and waters over
which the United States has jurisdiction, for the prevention,
detection, and suppression of violations of laws of the United
States. For such purposes, commissioned, warrant, and petty officers
may at any time go on board of any vessel subject to the
jurisdiction, or to the operation of any law, of the United States,
address inquiries to those on board, examine the ship's documents and
papers, and examine, inspect, and search the vessel and use all
necessary force to compel compliance. When from such inquiries,
examination, inspection, or search it appears that a breach of the
laws of the United States rendering a person liable to arrest is
being, or has been committed, by any person, such person shall be
arrested or, if escaping to shore, shall be immediately pursued and
arrested on shore, or other lawful and appropriate action shall be
taken; or, if it shall appear that a breach of the laws of the United
States has been committed so as to render such vessel, or the
merchandise, or any part thereof, on board of, or brought into the
United States by, such vessel, liable to forfeiture, or so as to
render such vessel liable to a fine or penalty and if necessary to
secure such fine or penalty, such vessel or such merchandise, or
both, shall be seized.

Along with similar Customs powers, Section 89 Coast Guard police authority
has been called the "most sweeping grants of police authority ever to
be written into U.S. law." [see for instance: La Fave s. 10.5(i).]
Read literally, s. 89 gives the Coast Guard plenary search and seizure
power over every vessel under U.S.

This statute, currently broadly due to our war on drugs, gives the Coast
Guard search powers over vessels that are much broader than similar search
powers over cars, houses, or RV's. For instance, for a peace officer to
search an RV, the PO usually does not need a warrant, but must have "probable
cause" to search the vehicle. The Coast Guard, on the other hand, has
statutory power to stop and search a vessel *even in the absence of probable
cause that a crime is being committed*, so long as the stop was for the
purpose of a 'safety and document inspection.' "