[MHml] Outdrives

Tue Feb 13 23:36:54 EST 2007

I am no expert on hydraulics but have for a long time wished that my 
saildrives (on my Catana 431) could come out of the water unless actually 
driving the boat. Upon pulling into Salinas, Puerto Rico I spotted a large 
Cat named Cat Sass which had two sail drives, one fixed to the inside wall 
of each hull at the aft, which rotated up and out of the water.  I talked 
to the owner who has had this boat for 15+ years and has nothing but good 
things to say about his deployable hydraulic saildrives.  Says he has never 
had a single problem with them, that they work better than any mechanical 
linkage (meaning normal transmission with gears and such) he has ever had, 
that it is lighter than an equivalent non-hydraulic unit, that it was put 
together with things available on the market more than 15 years ago (except 
for a custom made mount explicitly for his hulls), and that it made for the 
best possible sailing since their is zero drag.

So I guess it must be possible to do a good job of it.  I have hydraulic 
steering on my boat.  Some others complain about hydraulic leaks and such, 
but personally I have never had one since I bought the boat in 2002.  If I 
was going to replace my saildrives with something that could be totally out 
of the water I would definitely consider a hydraulic solution.

>Date: Mon, 12 Feb 2007 14:16:18 -0800
>From: Dan Frenette <Dan.Frenette at Sun.COM>
>Subject: Re: [MHml] OutDrive Legs (was PRM Transmissions)
>
>Be careful. I have talked a number of owners that tried hydrolics and
>didn't get the reliability or performance they expected. Now this is
>second and third hand information but when a sailor goes to every race
>for 30 years in a row doesn't start due to no engine then there is
>something challenging about the technology.
>
>This group doesn't normally stop at a challenged technology but there is
>something more so with the physics here.
>
>There are clearly good adaptations of this sort of thing on land but
>something about boats is a bit different.
>
>Dan Frenette
>
>K38BOB at aol.com wrote:
> > In a message dated 2/10/2007 3:53:58 A.M. Pacific Standard Time,
> > beiland at usa.net writes:
> >
> >     Regrettably the PYI unit I referenced is not being built any longer,
> >     and it
> >     was not a cheap unit
> >
> > Thanks Brian,
> > I actually was looking for that unit when I couldn't find a Sillette rep
> > in the US to ask about "Hydrodrive".
> >
> > Does anyone have any knowledge about the "hydrodrive" internals and
> > performance? I notice that Phillipe Kahn Pegasus has one.
> > http://www.pegasus.com/pegasus77/gallery/exterior/ext_11.htm Prop pretty
> > close to hull bottom?
> >
> > I'm considering the smallest one (Yanmar 2gm SD20 currently) perhaps
> > remote under cabin sole with shaft from current engine compartment
> > through bulkhead (c-drive)
>snip...
>
>
>------------------------------
>
>Message: 3
>Date: Tue, 13 Feb 2007 10:10:52 +1100
>From: Gary Pearce <gary at thepearces.com>
>Subject: Re: [MHml] OutDrive Legs (was PRM Transmissions)
>To: Informed discussion of multihull issues
>         <multihulls at steamradio.com>
>Content-Type: text/plain;  charset="iso-8859-1"
>
>On Tuesday 13 February 2007 09:16, Dan Frenette wrote:
> > Be careful. I have talked a number of owners that tried hydrolics and
> > didn't get the reliability or performance they expected.
>
>Yup,
>
>Rule 1: Simplest is nearly always best.
>
>I really love the system Peter & Toni Nice have on Tigger. Its just a big
>rubber band (OK toothed belt) driving the prop shaft which runs underneath
>the motor (i.e. the motor is fitted facing forward). Slip the belt off the
>drive shaft and onto the large "at anchor" generator and you have extra
>generator power if you need it. Delightfully agricultural. A rubber band
>inside a "Z" drive leg would be a fine thing if anyone made one.  A rubber
>band driving one of those inside out propellers at the end of a lifting leg
>would be ideal but ......(caution see rule 2)
>
>Rule 2: If you can buy it (or something very close) then don;t ever build
>it :-)
>
>Gary
>
>
>------------------------------
>
>Message: 4
>Date: Tue, 13 Feb 2007 10:16:26 +1100
>From: Paul Nudd <paulnudd at actionpotential.com.au>
>Subject: [MHml] WSL70
>To: Informed discussion of multihull issues
>         <multihulls at steamradio.com>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>
>Dan Frenette wrote:
> > The cost of the boats will expand to fill all possible money sources.
> > It's in the nature of racing to spend more than the other guy.
> >
> > So what are they doing to limit cash available for racing teams?
>-----------------------------------
>I'm not sure but I think at the hobie 16 worlds the equipment is
>supplied by the manufacturer. Racing teams can spend as much as they
>like on preparation but can't spend anything on the boat and can't
>change anything.
>In WSL the same applies. Each racing team will pay the same to lease a
>boat for the season. Strict one design. Where can they spend more money
>than the next team? Not on equipment, on team training I guess.
>PN
>----------------------------------
> > So 10' longer implies faster but the cats seem to be slower than the
> > tri's. Even a 10' shorter tri implies slower.
> >
> > What did they invent to make the cat faster? Remove the limit on mast
> > height?
>---------------------------------
> >> Dave Culp writes:
> >>  >Speaking of comparisons, I think I'd need to ask myself just exactly
> >>  >what this class of race boats offers, significantly different from
> >>  >ORMA 60s. OK, they're 10' longer. Are they faster? (ORMA best day's
> >>  >speed what, 670 miles?) Are they cheaper?
>---------------------------------
>ORMA 60 is a 'development class' intended for ocean racing. No
>comparison is valid. It doesn't matter if they are faster or slower,
>cheaper or more expensive. WSC 70 is not even a 'one design class'. It
>is not even a 'strict one design one manufacturer class' like a hobie 16
>or a laser. It is a 'race what we give you circus'. The boats will be
>exactly the same (except for sponsors signage). They have indicated they
>will have 12 teams but 14 identical boats, presumably spares to use in
>case of damage. I imagine that if a team believes they have been
>allocated a lesser boat they would be able to request re-allocation and
>if one team seems to be dominating they may have a forced re-allocation.
>Perhaps WSL might even have forced rotation of boats between teams.
>Coutts and Cayard are bright boys making an honest attempt to keep the
>equipment costs/team spending out of it to make it a proper test of team
>ability as well as an attractive and profitable spectacle. (in my
>opinion - probably not humble).
>PN
>
>
>------------------------------
>
>Message: 5
>Date: Mon, 12 Feb 2007 16:15:20 -0800
>From: Dan Frenette <Dan.Frenette at Sun.COM>
>Subject: Re: [MHml] OutDrive Legs (was PRM Transmissions)
>To: Informed discussion of multihull issues
>         <multihulls at steamradio.com>
>Content-Type: text/plain; format=flowed; charset=ISO-8859-1
>
>This belt sounds like a timing belt. There are a number of cars using
>this kind of technology. Everything has a down side but I don't see one
>with this. They could cast some really thin housings for this kind of
>drive. Aka very longer shaft bigger prop.
>
>Did they use an existing outboard lower unit or fabricate something of
>their own?
>
>How did they handle reverse?
>
>Snowmobiles use something like this with a variable transmission. I
>don't know if this would work without lots of air flow.
>
>Dan Frenette
>
>Gary Pearce wrote:
> > On Tuesday 13 February 2007 09:16, Dan Frenette wrote:
> >
> >>Be careful. I have talked a number of owners that tried hydrolics and
> >>didn't get the reliability or performance they expected.
> >
> >
> > Yup,
> >
> > Rule 1: Simplest is nearly always best.
> >
> > I really love the system Peter & Toni Nice have on Tigger. Its just a big
> > rubber band (OK toothed belt) driving the prop shaft which runs underneath
> > the motor (i.e. the motor is fitted facing forward). Slip the belt off the
> > drive shaft and onto the large "at anchor" generator and you have extra
> > generator power if you need it. Delightfully agricultural. A rubber band
> > inside a "Z" drive leg would be a fine thing if anyone made one.  A rubber
> > band driving one of those inside out propellers at the end of a lifting 
> leg
> > would be ideal but ......(caution see rule 2)
> >
> > Rule 2: If you can buy it (or something very close) then don;t ever build
> > it :-)
> >
> > Gary
> > _______________________________________________
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> >
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>
>
>------------------------------
>
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>End of Multihulls Digest, Vol 32, Issue 35
>******************************************