There is no equipment requirement regarding the crossing of water in a single-engine airplane unless that aircraft is operated for hire:
Sec. 91.205 Powered civil aircraft with standard category U.S.
airworthiness certificates: Instrument and equipment
(b) Visual-flight rules (day). For VFR flight during the day, the
following instruments and equipment are required:
(12) If the aircraft is operated for hire over water and beyond
power-off gliding distance from shore, approved flotation gear readily
available to each occupant and at least one pyrotechnic signaling
device. As used in this section, ``shore'' means that area of the land
adjacent to the water which is above the high water mark and excludes
land areas which are intermittently under water.
In reading a required-equipment regulation farther down part 91, one may confuse this next regulation as applying to all airplanes:
Sec. 91.509 Survival equipment for overwater operations.
(a) No person may take off an airplane for a flight over water more
than 50 nautical miles from the nearest shore unless that airplane is
equipped with a life preserver or an approved flotation means for each
occupant of the airplane.
(b) Except as provided in paragraph (c) of this section, no person
may take off an airplane for flight over water more than 30 minutes
flying time or 100 nautical miles from the nearest shore, whichever is
less, unless it has on board the following survival equipment:
(1) A life preserver, equipped with an approved survivor locator
light, for each occupant of the airplane.
(2) Enough liferafts (each equipped with an approved survival
locator light) of a rated capacity and buoyancy to accommodate the
occupants of the airplane.
(3) At least one pyrotechnic signaling device for each liferaft.
(4) One self-buoyant, water-resistant, portable emergency radio
signaling device that is capable of transmission on the appropriate
emergency frequency or frequencies and not dependent upon the airplane
(5) A lifeline stored in accordance with Sec. 25.1411(g) of this
Sound convincing for all small single-engine airplanes? Sure. But when you take a step back and check the applicability of the subpart having authority over this regulation (Subpart F), you will note this:
Subpart F_Large and Turbine-Powered Multiengine Airplanes and Fractional
Ownership Program Aircraft
Sec. 91.501 Applicability.
(a) This subpart prescribes operating rules, in addition to those
prescribed in other subparts of this part, governing the operation of
large airplanes of U.S. registry, turbojet-powered multiengine civil
airplanes of U.S. registry, and fractional ownership program aircraft of
U.S. registry that are operating under subpart K of this part in
operations not involving common carriage.
Hence, this regulation ALSO does not apply to all light single-engine airplanes.
So, if you are in a light single engine airplane for private use, there is no over-water equipment requirement. These regulations only apply to aircraft operated for hire, or are large, turbojet-powered multiengines, or are operated under a fractional ownership program.
"About the only way to look at it, just a pity you are not POTUS KFLLCFII, seems as if we would all be better off."