The Get-Home System
Above: A classic wing engine installation using a V-drive transmission. With their own shafts and props, wing engines offer significant redundancy. Right: Many point out one drawback to wing engines, they use the same fuel as the main engine. However, in some cases builders have corrected that shortcoming by including an isolated fuel tank for wing engine use.
The outboard shaft also imparts an effect on the vessel’s
tracking, requiring a steering offset of as much as 20
degrees, which can make life hard on the autopilot, not to
mention the helmsman. Still, with a little practice, steering
is relatively easy when the wing is used, and while it will
get you there, don’t expect to break any speed records.
In my experience most wing engines, depending on their
horsepower, will propel a vessel in moderate wind and
wave conditions at roughly half the hull speed.
The wing’s external running gear does impart drag,
affecting fuel economy to some degree. In order to
reduce drag, wing propellers are typically of the folding
or feathering variety (more often the former), and
herein lies one of the wing engine’s liabilities. If not
information on their product, specifically stated as
being for this article, went unanswered. It is well worth
establishing a dialog with the manufacturer to gauge and
ensure adequate support if you intend to utilize one of the
proprietary get-home systems before making a decision.
WING ENGINES
Surely among the most ubiquitous of mechanical
get-home options is the stand-alone wing engine. This
approach represents the most reliable, and perhaps the
most costly, get-home option. Wing engines essentially
transform a single-engine vessel into a twin screw, albeit
with a significant disparity in the power between the two
engines. A wing engine itself is often no different than
the main, just smaller. It typically includes all of the same
accessories, options, and related components, and falls
under the same manufacturer installation requirements
(which should be verified). In many cases, to aid in the
utilization of space, wing engines will employ a V-drive
transmission, wherein the wing engine shaft passes under
the engine.
The wing engine shaft passes through the hull via a
stuffing box and shaft log assembly, just like that of the
main engine. However, unlike most main engine shafts,
which pass through the keel, the wing shaft relies on a
strut for support. One of a single-screw, full-keel vessel’s
primary attributes is the protection it affords its running
gear in the event of a grounding or collision with a
floating object. The wing shaft, strut, and propeller are
afforded no such protection and are susceptible to damage
or fouling from floating or semi-submerged debris, fishing
gear, lines, nets, etc.
properly maintained they can fail to deploy when needed,
especially if used infrequently. On several occasions I’ve
encountered wing props that required a significant amount
of effort for me to open during haulout inspections.
Clearly all gear aboard your vessel benefits from being
used regularly, perhaps none more so than engines;
main, wing, and generator. On at least one occasion I’ve
replaced a wing engine that seized from lack of use.
Moisture accumulation inside the cylinders, which likely
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passagemaker.com September 2011
