Based on a study of potential uses of small
WIG craft (less than 10 tons gross), Seair compiled a list of specific
characteristics which should be met if they are to be successful as safe,
practical marine transportation. Seair has used these proposed characterictics
since 1986 to guide the development of key technologies for their WIG
designs. Important requirements and objectives included these
of WIG Design :
- Remain "boat-like" in most respects: Maintain
good "boating" characteristics (running on plane at below
lift-off speeds---critical for operating in high traffic areas, narrow
rivers, or any area with restricted maneuvering room). Also good cockpit
visibility for seeing and avoiding other marine traffic. Have practical
(reasonably "boat-like") docking / mooring capability.
- Avoid IMO "Type C" which is unable
to capture the cost savings of licensing as a "boat".
- Design for reasonable operating speed margin between
initial lift-off and maximum cruise speed.
- Moderate power required for takeoff (horsepower-to-weight
ratio of < 7 % ) with reasonably slow lift-off speed and short takeoff
runs (< 30 seconds or so). Also have ability to takeoff in other
than "nearly calm" wind and waves.
- Good resistance to blow-over if "bounced"
by wind or waves above normal height, and no dangerous loss of stability
or control at maximum speeds. Be able to safely recover from significant
pitch or roll upsets.
- Have good maneuverability (i.e. "boat-like"
turn radius --or better-- at cruise or harbor-taxi speeds) and the ability
to quickly execute emergency stopping or other collision avoidance maneuvers.
- PAR takeoff assistance (if required) must not
be too mechanically complex, costly or noisy for commercial use.
- Props or fans need to be located in areas not prone
to debris damage, or sand and spray erosion, and should not create a
potential hazard to dock attendants, nearby boaters, or other personnel.
- 1 to 6-seat craft should be conveniently folded
or dismantled for transport or trailering and should have walk-on "deck"
areas for boarding, engine access (or for swim platform, sun pad, etc.).
- Avoid ultra-light aircraft type construction
that is not robust enough for serious marine use and avoid "low-cost"
FRP boat construction that is too heavy to fly well (use aircraft structure
Every one of of the historical WIG
examples investigated during Seair's survey exhibited at least four deficiencies
relative to the proposed list. During the last half of the 1990’s
several WIG developers emerged with "next generation" designs
that have addressed some of the previous shortfalls, promoting the formal
recognition of WIG’s by the IMO and various Coast Guards. It is
good to keep the above factors in mind when making your own evaluation
of any current or future WIG craft.
Material on this website is
copyrighted ©2000 by C.P.Nelson, Seair Craft Inc.