My Canadian commercial licence is endorsed as SMELS which stands for Single and Multi-engine Land and Sea. ( May also denote a lack of personal hygiene ).
Except for 1 circuit in a CL215 and another 3 in a PBY Canso I have only flown Float equipped aircraft on water such as the Beaver, Otter and 180/185/206 Cessna. I got my rating on a 65 horse J-3 Cub on floats ( what tired horses they were -LOL-) and what fun times they were too.
As noted below there does not seem to be any difference between "Float" equipped aircraft such as a Beaver or "flying Boats" such as a lake amphibian seaplane or a RC-3 Seabee or even a PBY Canso which would however require a type rating being over 12500 LBS.
From:
Part IV - Personnel Licensing and Training - Transport Canada
DIVISION X - AEROPLANE CLASS RATINGS
421.38 Requirements
(1) Seaplane Rating - Requirements
(a) Experience
(i) An applicant for a seaplane rating shall complete a total of 7 hours of seaplane training, including:
(amended 1998/03/23; previous version)
(A) a minimum of 5 hours dual instruction, and
(amended 1998/03/23; previous version)
(B) a minimum of 5 takeoffs and landings as sole occupant of the aeroplane, except for two crew aircraft, in which case the takeoffs and landings shall be done as pilot-in-command.
(ii) The following exercises shall be included in the seaplane training:
(A) taxiing,
(B) sailing,
(C) docking,
(D) takeoffs, and
(E) landings, and
(F) as conditions exist, operations on glassy water, rough water and in crosswind conditions.
(b) Skill
Within the 12 months preceding the date of application for a seaplane rating, an applicant shall have successfully completed a qualifying flight under the supervision of a Transport Canada Inspector or a person qualified in accordance with CAR 425.21(6) by demonstrating the level of skill specified in the Instructor Guide - Seaplane Rating (TP12668).
(amended 2000/09/01; previous version)