Re: [OMC-Boats] 1969 silverline riviera hole shot

Carl,

Doug's comments are right-on the money.

You didn't mention your boat's gross weight or length, but assuming
it's typical, you can check your boat's theoretical performance using
this calculator:
http://hhscott.com/evinrude/docs/BSLAC.htm

What this calculator will basically reveal our the laws of physics,
which you are up against.

I have done a ton of waterski pulling in a variety of situations with
my tri-hull Evinrude sportsman. I have a disadvantage that you don't
have and that is I do it at 7500 Ft Above Sea level so I give 25%
right away.

Three things you can do to improve getting out of the hole:

1) Prop properly: Use a 13-inch OMC SST. The stainless steel has less
flex and will bite better. Next best is a 14 inch Alum. The 12-inch
prop is too much of a compromise. You will give up fuel economy and
top speed. (You could also change upper case gear ratios but that
would be very expensive and not practical).
2) Install trim tabs. They when placed in the down position, they will
raise the stern (Lower the bow) and help the boat get on plan better.
Conversely you can move all you passengers to the bow (not very
practical or safe).
3) A foil (which extends the area and lift of the anti-ventilation or
cavitation plate) will help somewhat, but in my experience it has the
least effect and that's why I've placed it third in this list. It does
help in turns to keep the prop from catching air and "blowing out"
resulting in over-revving. I've got a String-Ray (and like it) from
Marine Dynamics: http://www.marine-dynamics.com/ But don't expect it
to perform miracles. It is probably the most cost-effective
improvement you can make.

Lee Shuster

On Jun 6, 2009, at 3:08 PM, DOUGLAS JULIEN wrote:

> Hi Jerry:
>
> The Silverline is longer but lighter than a Sportsman 155, so hole
> shot should be fine. The hydrofoil is mostly useful for reducing
> porpoising - sometimes a problem with tri-hulls. If I were you I'd
> make sure the engine is performing properly, first, then I'd try a
> lower-pitch prop. With props you must choose what is more important
> - acceleration out of the hole, or top speed/fuel economy. With a
> lower-pitch prop your acceleration will increase, but your putt-putt
> speed will decrease, so you won't be ramming so many docks.
>
> -Doug Julien
>
>
>
> --- On Sat, 6/6/09, wheresjerry@... <wheresjerry@...> wrote:
>
> From: wheresjerry@... <wheresjerry@...>
> Subject: [OMC-Boats] 1969 silverline riviera
> To: omc-boats@...
> Date: Saturday, June 6, 2009, 1:10 PM
>
> Going to finally get my boat in the water this weekend for it's
> second season in almost 20 years. I have been in the process of
> rebuilding the boat and the usual stuff it has required after
> spending 18 years in a garage. I have an OMC Stringer Buick v6 w/
> 155 hp.
>
> Last season, I noted it had trouble getting out of the hole, (heavy
> tri-hull) and had looked into the possibility of getting a SE
> Sport 300 Hydrofoil, question is, has anybody had good luck out
> there with a similar vintage boat?
>
> Thanks!!
>
>
> karl/wheresjerry banach
> 105 browns pasture rd
> strafford, nh 03884
>
>
>
> -----Inline Attachment Follows-----
>
> _______________________________________________
> OMC-Boats mailing list
> OMC-Boats@...
> http://lists.ultimate.com/mailman/listinfo/omc-boats
> _______________________________________________
> OMC-Boats mailing list
> OMC-Boats@...
> http://lists.ultimate.com/mailman/listinfo/omc-boats
Received on Sunday, 7 June 2009