[Public-list] Another outboard discussion

[Don Campbell]

J:
"However, there's a brisk market in used outboards, and 4 strokes bring
a
premium. They're hard to come by, so they must be doing something
right...???"
I am under the impression that the EPA has legislated 2 strokes off the
market, if not now in the near future.

"I have never understood people's concern with being able to
use the motor in chop."
    You have contradicted this in your reply to Mike Lehman with
motorboat traffic in Annapolis.
    As for prop size, I have not tried Yahama, but most manufacturers of
small outboards never contemplate hull speeds of 6 feet a second or
less, and so finding a prop for that is not easy. Many are 4 blades too.
The biggest we could get for a 9.9 for the AL22 was under 7 inches in
diameter because of the anti-cavitaiton plate. I imagine you will be in
dire straights to find a prop for a 25 HP unit for speeds of 6 feet per
second. Check that one out for interest!
    Gelinas had the problem of needing storage space for a
circumnavigation sail, so removed the motor for weight, uselessness and
space. He still sails most of his miles. As I understand it Jean du Sud
is in France at the moment.
    On a quick look at the waterline moments for motors that weigh 120
lbs with mounting bracket, they do look as if they will balance about
equally. That won't hold for a 25 hp unit whether side or transom
mounted. The A4 does not weigh 500 lbs though.  Fuel weight will be
nearly the same or worse for the outboard since we get only about 6
miles per 2 gallons on the 22 with a 9.9 2 stroke Nissan. (The 4 stroke
would not fit into that boat and they are somewhat better on fuel).
Where one stores the fuel may matter. I think you will want three 5
gallon tanks for most trips for safe returns, since one tank out,  one
tank home and one for safety is the general safety rule.
    As for towing vs mounted efficiency on an outboard, expect
differences because of waterflow to and from the prop. The point was
though that small engines do not do things quickly.
    Also take a look at the design of Michigan Wheel's MP2 two blade
prop if you want to see surface area on the disc with a 2 blade. Janski
really likes the way that prop propels Viva II with an Atomic 4.
Apparently much less propwalk especially in reverse. I have not driven
that boat yet but hope to this month. See Spring 2002  for pictures in
the Canadian Newsletter at
www.alberg.ca
    As for the hole left once the shaft is removed, glass it in since it
is not difficult to replace the cutlass bearing holder and drill a new
hole. The 5200 seal on the inside of the hull ought to solve the
differences.
    As for race rules, anything but an inboard would not qualify to race
as a one-design boat as I interpret section 4 and section 18, although
replacement inboard motors have never been questioned in the Canadian
fleet, even when heavy A4s have been replaced with lighter Yanmars. We
still make no allowance for time differences and have single cylinder
Bukhs, A4s, Grey Marines and Yanmars in the current racing fleet.
Don
#528


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