There was no visible corrosion on the outside of the rod. It was on
the broken section. Showed up as small rust dots over most of the
surface. The pin was supported above and below the loaded area so
the rod was purely in sheer. No way it could bend without breaking
one of the supports fiorst.
regards,
Rob
On Thu, Apr 16, 2009 at 3:13 PM, Doug Haines <doha720@yahoo.
>
>
> are these the pins in the hinges top and bottom?
> mine is a solid ss 12mm? was bent a little from usage. can always expect
> high loads here,
> unless fit in very snug to the tube.
> so the tube is nylon or carbon.
> that means it was under size after wearing down rusty, so had play which
> gave bigger loasds so thinner diameter broke?
>
> --- On Thu, 16/4/09, Arto <ahakkara@yahoo.
>
> From: Arto <ahakkara@yahoo.
> Subject: [harryproa] Re: Rare Bird's Race and stainless rudder pin failure
> To: harryproa@yahoogrou
> Date: Thursday, 16 April, 2009, 4:59 PM
>
> Fast google search indicates that titanium goes well with carbon fibre.. Few
> studies I found say that there should be no galvanic action between titanium
> and carbon fibre. Check with someone who really knows before deciding
> though. Another benefit is that titanium and carbon fibre have similar heat
> expansion properties.
>
> Arto
>
> --- In harryproa@yahoogrou ps.com.au, "Robert" <cateran1949@ ...> wrote:
>>
>> Provided there is no galvanic action,
>> this is a possibility, but there is a possibility of galvanic action with
>> carbon. It is a big problem for aluminium.
>> --- In harryproa@yahoogrou ps.com.au, arttuheinonen@ wrote:
>> >
>> > Hi,
>> >
>> > Titanium is strong and light and resists corrosion very well.
>> > It is expensive, but these are vey important parts, so why not
>> > titanium??
>> >
>> >
>> > -Arttu
>> >
>> >
>> >
>> > Hi all,
>> > >
>> > > We gave the fleet 5 minutes start off Manly and followed them out of
>> > Moreton Bay. The big dedicated race boats steadily drew away from us
>> > cruisers. All the other boats had down wind sails
>> > (genoas/genniker/ screechers) and the breeze was either too gentle or
>> > too
>> > far abeam for us to use the kite, so we were immediately at a
>> > disadvantage. Despite this we caught and overtook the Seawind halfway
>> > out of Moreton Bay, and overtook Catalina on a broad reach before they
>> > overtook us again downwind with their extra sail.
>> > >
>> > > After that we kept Catalina in sight for the next 80 miles, before her
>> > sternlight faded in the distance off Fraser Island. Rob hit the sack at
>> > 8pm and for the next 3 hours I enjoyed blasting north through the night
>> > in 1-2 meter seas with 1-2 meters chop, in a 15-20 knots Easterly, speed
>> > ranging from 9 to 13 knots. Front rudder was left to do its own thing
>> > (swinging 5 degrees maximum) and the aft rudder easily steered, mainly
>> > by foot, as I sat on the comfy seat.
>> > >
>> > > When Rob took over he reefed both main and jib, as the winds were
>> > forecast to increase. He still was doing 8-9 knots and was still
>> > steering only with the aft rudder. He'd only been at the helm less than
>> > an hour when he heard a small bang, and though the boat was still
>> > steering OK, he took a look around and discovered the forward rudder
>> > hanging sideways. The 19mm stainless rudder pin had broken at the lower
>> > mounting point (where it passes through an incredibly fine carbon mount
>> > - it is about 1 cm x 1cm in cross-section, and there are two of them).
>> > The mounting point was still intact! The top quadrant ( see pictures on
>> > harryproa.com) was broken when the cassette went sideways. It is
>> > repairable.
>> > >
>> > > We had to retire , and when we had motored back to Mooloolabah,
>> > discovered that the shaft was corroded almost completely through. The
>> > reasons? The best suggestions I've heard are
>> > > 1. Stainless of less quality than specified, and/or
>> > > 2. Galvanic action between stainless and carbon
>> > > Any comments?
>> > >
>> > > I think I will replace both pins with carbon fibre rod - or maybe go
>> > for 321 stainless - boatbuilder comments?
>> > >
>> > > Despite the failure I'm very impressed with the Visionarry's overall
>> > performance:
>> > > - very comfortable motion in messy seas (my other half had only
>> > previously had ONE gentle sail on Moreton Bay, and she still wants to do
>> > more sailing)
>> > > - easy sail handling, just a couple of steps from the cockpit
>> > > - quick shunting ( our best time about 30 seconds )
>> > > - excellent upwind performance (45 degrees off true wind)
>> > > - easy control downwind
>> > > - very fast on reach - close to wind speed in ideal conditions
>> > > - could easily handle a lot more power and be seriously competitive
>> > > - well suited to short-handed cruising
>> > >
>> > > Cheers,
>> > >
>> > > Col Campey
>> > >
>> > >
>> > >
>> > > --- In harryproa@yahoogrou ps.com.au, Mike Crawford <jmichael@> wrote:
>> > > >
>> > > >
>> > > > My guess is that the posts are the vertical axles for the two wheels
>> > > > (not sure "wheels" is the right word) on which the rudder cassettes
>> > > > are
>> > > > mounted. The rudder would certainly fail if one of these fail.
>> > > >
>> > > > I can't see this being a flaw in the design, though. Because they
>> > > > are
>> > > > so short, and handle very little bending moment, these posts should
>> > > > have
>> > > > lower loads than a normal multihull rudder stock. And anything that
>> > > > fails due to corrosion is likely to... fail due to corrosion.
>> > > >
>> > > > That said, I do look forward to seeing how the new beam-mounted
>> > > > design
>> > > > works on Blind Date this summer. It's a nice way to handle kicking
>> > > > up
>> > > > in both directions, balancing the rudder forces as they are raised,
>> > > > and
>> > > > concentrating forces on a very strong structural member.
>> > > >
>> > > > - Mike
>> > > >
>> > > >
>> > > > Doug Haines wrote:
>> > > > >
>> > > > >
>> > > > > so it was 316 SS? rare bird was the board in case design lasts i
>> > > > > recall.
>> > > > > was it changed to a post?
>> > > > > or you mean the shaft in the board was steel? very strange.
>> > > > >
>> > > > > --- On *Tue, 14/4/09, Robert /<cateran1949@ >/* wrote:
>> > > > >
>> > > > > From: Robert <cateran1949@ >
>> > > > > Subject: [harryproa] rare bird.
>> > > > > To: harryproa@yahoogrou ps.com.au
>> > > > > Date: Tuesday, 14 April, 2009, 9:28 PM
>> > > > >
>> > > > > Rare bird suffered a corroded rudder post. It was supposed to be
>> > > > > stainless 3.6.1. The posts are going to be replaced with carbon
>> > ones.
>> > > > > The owner reckons it was remarkably comfortable at 13 knots in a
>> > > > > bit of a sea
>> > > > >
>> > > > >
>> > > > >
>> > > >
>> > >
>> > >
>> >
>>
>
>
>
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