This is going to make one heck of a video when the first one works.
PCKing
----- Original Message -----
From: "Mike Crawford" <jmichael@gwi.net>
To: <harryproa@yahoogroups.com.au>
Sent: Monday, July 03, 2006 7:27 AM
Subject: [harryproa] Re: Mast raising
> Hey Robert,
>
> How is the new job?
>
> The support system you describe should work well if the lw hull is
> stored upright next to the ww hull on the trailer. For a Visionarry,
> though, that puts me about 20cm past the unescorted wide load limit, so
> one or both hulls would have to get a bit narrower.
>
> The idea of storing the lw hull on its side, beneath the wing deck,
> makes supporting the ww hull more of a challenge, but kills two birds
> with one stone: neither hull has to change size, and the lw hull is
> already on its side ready for the mast. It does get away from my dream
> of collapsing the boat on the water and floating it onto a standard
> trailer, though.
>
> Since the beams aren't parallel to each other and perpendicular to the
> hulls, I'm having a hard time imagining how an Farrier-type system would
> work. The same geometry would also make it difficult to use the
> Dragonfly system. The only one that's making sense to me at the moment
> is the cat2fold scissors system.
>
> However, I'm sure there are other ways to accomplish the goal. My
> only doubt involves a tilting/folding system. Unless the trailer could
> take the boat out sideways, or I could remove the mast while on the
> water, that could make it very difficult to launch from anything other
> than a wide open ramp.
>
> Is the dream worth it in terms of added weight, complexity, and
> chances for failure? I'm not so sure. Of course, my goal is to use the
> trailer only two to four times per year, so that makes the inconvenience
> of box beams and a funky trailer less of an issue.
>
> Are there any photos, CAD images, or links that describe Jim
> Shanahan's system in more detail? I found a few references to it in
> early posts, but haven't seen anything that describes how it works. One
> message mentioned something about being lighter and stronger than
> conventional beams. If so, that would be impressive. The righting
> aspect is also intriguing.
>
>
> - Mike
>
>
>
> Robert wrote:
>
>> -G'day Mike
>> I was thinking on similar lines but don't se much problem holding up
>> the ww hull. There is not an enormous weight off centre and a
>> vertical bit of box section on the ww side triangulated at the base
>> should provide enough support for the hull with a couple of tie down
>> straps to hold it against. Either that and/or a support under the
>> junction of the wing deck and hull. This would have to be to the lw
>> side of the c of g.of the www hull on its own.
>> If the crossbeams had a temporary controlling system such as a
>> farrier wishbone with a sleeve to allow sliding of the crossbeam, or
>> even a complete folding system as designed by Jim Shanahan then the
>> only difficulty is moving the lw hulls off the trailer and onto a
>> trolley as everything else can be controlled with a couple of
>> winches. Jim's system makes a lot of sense and would even allow
>> righting from a complete overturning.
>> My personal preference is to launch a folded system where the boat
>> can then be brought side on to shore and the mast then inserted-
>> possibly with sail attached. The crossbeams get winched out with
>> water supporting the system and you're away.
>> I have tried to imagine taking the folded boat out onto the water
>> and inserting the mast from the water. It seems theoretically
>> possible but would probably be excessively difficult in practice.
>>
>> On another issue, I was wondering if there was any wat to get round
>> the dependance on carbon for making a free standing mast without
>> excessive weight. The closest I could come up with was , while
>> looking through a website on making bamboo fly rods, the testing of
>> tensile and compressive strengths and Young's modulus of strips of
>> bamboo. Rough calculations give a mast made of quality bamboo strips
>> a weight of about 2.5 times that of carbon. The technology for
>> utilising bamboo has come some way to making this practical, but
>> organising supplies off stream from flooring manufacturers would be
>> horrendous
>>
>> Robert
>>
>> -- In harryproa@yahoogroups.com.au, Mike Crawford <jmichael@g...>
>> wrote:
>> >
>> >
>> > If you can keep that leeward hull in place as it rotates from
>> > horizontal to vertical, then there shouldn't be any problem with
>> the
>> > size of the mast. Given the length of the beams, a #14 winch at
>> 16:1
>> > should be enough to bring the leeward hull into place with a 22m
>> wing
>> > mast. Though I'm not familiar with the size of winches used on the
>> > Harry's, my guess is that you'll have at least a #14, which is the
>> > smallest self-tailing size offered by some vendors.
>> >
>> > If this is not enough, it would be simple to double the purchase
>> with
>> > a block. If you want even more than 32:1, then you could have a
>> single
>> > line going from the trailer to the first beam, back to the trailer,
>> up
>> > to the second beam, back to the trailer again, and then up to the
>> > winch. That might be even be enough to lift your tow vehicle if
>> you put
>> > some muscle into it..
>> >
>> > ---
>> >
>> > For me the question then becomes how much help you're willing to
>> > require. If you can get a few people to lend a hand, then the
>> Harrigami
>> > setup described in the article should be fine. It's certainly the
>> > simplest and cheapest way to go, and there's a lot to be said for
>> both.
>> >
>> > I'd probably choose to spend more on a trailer to help ease the
>> > process, though. This would be partially to save on boatyard
>> costs, and
>> > partially to allow two people to launch in areas that don't
>> necessarily
>> > have paid help.
>> >
>> > I think even a Visionarry could be kept to an 11' / 3.3m
>> trailering
>> > width if the leeward hull could be stored on its side on the
>> trailer
>> > beneath the cockpit. My first thoughts on this would be to:
>> >
>> > - Create a bunk that could hold the ww hull upright on its own,
>> >
>> > - Create a detachable moving bunk for the lw hull with its own
>> > wheels that could be lowered and used to move the hull out away
>> from the
>> > trailer,
>> >
>> > - Add two long horizontal arms that could be used to hold the
>> lw
>> > hull in place the proper distance away from the ww hull, as well as
>> keep
>> > the trailer assembly together when launching and retrieving the
>> proa,
>> >
>> > - Give the lw hull bunk assembly the ability to pivot to
>> vertical
>> > without sliding towards the ww hull and trailer,
>> >
>> > - Add some sheet blocks to the trailer and akas through which
>> the
>> > winch line can be run,
>> >
>> > - Add two short vertical arms with soft rollers that could be
>> > inserted into the main trailer and used to catch the beams as they
>> > rotate down to horizontal,
>> >
>> > - Add some block attachment points to the lw hull so that it
>> can be
>> > winched tightly towards the ww hull once the beams are in place.
>> >
>> > I'm not exactly sure how this would be done in a real world
>> situation,
>> > though.
>> >
>> > The bunk keeping the ww hull vertical would need to be pretty
>> strong,
>> > especially if it's going to hold everything in place while on the
>> road.
>> > Perhaps it could be supported while by the lw hull bunk once it is
>> in
>> > place under the ww hull, and by a temporary support arm under the
>> > cockpit when the lw hull bunk is away from the main trailer.
>> >
>> > The lw bunk might need a roller bearing and expansion arm/track
>> to
>> > support it until it is moved far enough from center to get the
>> inboard
>> > wheels down (assuming the outboard wheels can be dropped while the
>> > trailer is still whole). The wheels would also need to pivot 90
>> degrees
>> > to make the transition from assembly to launch. Alternately, there
>> > could be two sets of wheels, but that seems a bit excessive.
>> >
>> > Ideas on how to improve this setup, especially on how to make
>> that lw
>> > hull bunk work, are welcome. I don't mind seeing my ideas trashed
>> as
>> > long as something better results. Rob could probably solve this in
>> a
>> > weekend if I were actually building a boat, but I've got five years
>> left
>> > of lurking in this group before I get to that stage.
>> >
>> > - Mike
>> >
>> >
>> >
>> > oceanplodder2003 wrote:
>> >
>> > > Saw that, my concern was at what mast length would it become an
>> issue,
>> > > considering that if I go for Rob's una rig I'm assuming the mast
>> must
>> > > be taller, and I think Harry's is longer than Harrigami to begin
>> with.
>> > >
>> > >
>> > >
>> > >
>> > >
>> >
>>
>>
>>
>>
>>
>
>
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