Hi Herb,
Some points I have considered when preparing to build my Harry.
I agree very much with what Rudolf says about clearance. I am going for 600mm clearance for the bridgedeck, with even less in the saloon /cockpit area and a full 1m clearance of the crossbeams at the lw end when resting. This reduction in clearace in the cockpit saloon allows a lower roof to the saloon and less windage. As the bow depressses when sailing this decreases significantly. I am constrained to under 15m lw hull as after that regulations become a licorice allsorts of trouble.
At full drive with full load, the bows are expected to depress to about 850mm, leaving about 50mm above water. This leaves the transom just abot to lift clear and the ww hull pretty light on the water. This leaves 600mm clearance for the front beam in flat water. 600mm is not much in the way of waves. You are going with four foot shorter bows.
The wave resistance very quickly comes into play with these boats so this is why I am going with about a 14:1 ratio at 680mm with 400 fully loaded draught at rest for the ww hull with a flare above to deflect some of the spray.I am going slightly finer ratio for the lw hull at 900mm
I will be having the rudders on a mini beam set in a slight flare on the edge of the lw hullat 4.6m from the centreline. This is not so much for trying to get them closer to the ends but to allow a kick up system and clear beams. I want to keep the beams clear as it is to be able to be telescoped to 4.2m(42 decametres) (I have read the many books of the trilogy and sometimes the exercise seems like needing an improbability drive)
About the fore aft stability, the loads are generally regarded to be less than the loads on the beams holding a ww hull up in the air in bouncy seas, so if the beams are a box section with a carbon rod in each corner then all that is needed is to make the top and bottom panels the same as the side panels.
The sheets need to be taken to the cockpit directly to prevent being taken aback.
I think this just about eliminates the need to drag those crossbeams through the water;<)
I personally cannot see why the rudders need to turn 360. If hove to, then hopefully the ww hull will stay to ww and the rudders can simply lie at right angle. I would prefer to lift them and hang out a drogue on a bridle and have the bows to the seas.
Sangduen is a beautiful name. Look forward to seeing them on the water.
regards
Robert
--- In harryproa@yahoogrou
>
>
>
>
> Hi Robert,
>
> Thanks for the comments. Here are some of my considerations, which will one date go in the file as notes.
>
> I did some thinking about the wide ww hull and decided that it has the advantages of providing a sort of spray rail and reducing increased draft with increased load. I expect the boat to be overloaded more often than underloaded. It does have the disadvantage of increased wetted surface, but I calculated the increase as about 4-5% compared to a perfect half circle at typical designed load. I felt this was a good tradeoff because the increased wetted suface could be overcome by incrased light air sail area (perhaps about 10% increase in drifter size assuming it is about equal in size to working sail area).
>
> Actually the rudders are about as close to the lee hull as I can get them (.4m) and still have complete circular swinging room assuming .5m chord. I am perfectly happy to move them closer if it can be done. I decided on circular swinging room so I could put the rudders in any position when lying ahull or hove to in a storm.
>
> The main beam strains are intended to be taken by the central beams. The fore and aft beams are there only to hold the rudders, provide sheet attachment and stabilise the ww and lw hulls. That is why the fore and aft beams are splayed, to maximize the hull stability and get the rudders as far aft as possilbe. Given Rudolf's recent experience this may have been a good idea.
>
> The 42 foot length on the lw hull is actually just a joke based on Douglas Adams' books (e.g., So long and thanks for all the fish). Hence the type name Answerharry. I am also tempting fate by naming the boat after my wife - Sangduen (it translates as roughly as Moonbeam).
>
> Best regards
> Herb
>
> --- In harryproa@yahoogrou
> >
> >
> > Hi Herb,
> > It looks pretty good to me. I am not sure about the width of the ww hull. I am going skinnier and deeper (700mm wide and 350-400 deep) but Farrier reckons his wider centre hulls go just as well or even better so I can't say that it is a bad idea going that wide. I am also going longer (50') but can understand constraints on length. I would have thought that 40' would have been a more frequent constraint. I like the idea of a splayed mast system with the attached rudders, though I would go as close to the lw hull as possible with the rudders, but it does lead to constraints on how the beams are attached
> > I also hope the telescoping mast works.
> >
> >
> > --- In harryproa@yahoogrou
> > >
> > >
> > >
> > > Thanks Rob,
> > >
> > > I am some time off from committing to anything at the moment. Still don't have a shed built.
> > >
> > > At the moment I am more interested in feedback on the layout, beams, rudders, etc. than the rig.
> > >
> > > I think it would be quite easy to subsititute an easyrig for the telescoping mast as the first version I drew had the easyrig. However, the more I think about the telescoping mast the more attractive it seems, so I really hope you don't find it is a disaster:)
> > >
> > > Thanks for your (and everyone's) help.
> > >
> > > Best regards
> > > Herb
> > >
> > > --- In harryproa@yahoogrou
> > > >
> > > > Looks really good. However, I suggest you wait until we have some rig
> > > > results before you commit. Should not be too long to wait, panel production
> > > > for Solitarry has started.
> > > >
> > > > regards,
> > > >
> > > > Rob
> > > >
> > > > On Mon, Oct 12, 2009 at 10:03 AM, squirebug <squirebug@> wrote:
> > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > Hi Gardner,
> > > > >
> > > > > I have uploaded a pdf version.
> > > > >
> > > > > Best regards
> > > > > Herb
> > > > >
> > > > > --- In harryproa@yahoogrou
> > > > > Gardner Pomper <gardner@> wrote:
> > > > > >
> > > > > > Hi,
> > > > > > Is it possible for you to put it up as a PDF or image file of some sort.
> > > > > I
> > > > > > am definitely interested in looking at it, but I don't want to install
> > > > > > OpenOffice on my mac just for this one thing.
> > > > > >
> > > > > > - Gardner
> > > > > >
> > > > > > On Fri, Oct 9, 2009 at 7:24 AM, squirebug <squirebug@> wrote:
> > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This is a preliminary design for a cruiser I might start building next
> > > > > > > year. Any and all comments/criticisms welcome.
> > > > > > >
> > > > > > > It is rendered in odg format, which theoretically is readable by newer
> > > > > > > versions of microsoft, but it is probably much easier to download
> > > > > openoffice
> > > > > > > for free from www.openoffice.
> > > > > > >
> > > > > > > Best regards
> > > > > > > Herb
> > > > > > >
> > > > > > >
> > > > > > > --- In harryproa@yahoogrou
> > > > > 40yahoogroups.
> > > > > > > harryproa@yahoogrou
> > > > > 40yahoogroups.
> > > > > > > >
> > > > > > > >
> > > > > > > > Hello,
> > > > > > > >
> > > > > > > > This email message is a notification to let you know that
> > > > > > > > a file has been uploaded to the Files area of the harryproa
> > > > > > > > group.
> > > > > > > >
> > > > > > > > File : /Answerharry/
> > > > > > > > Uploaded by : squirebug <squirebug@>
> > > > > > > > Description : Cruiser for a couple.
> > > > > > > >
> > > > > > > > You can access this file at the URL:
> > > > > > > >
> > > > > > >
> > > > > http://au.groups.
> > > > > > > >
> > > > > > > > To learn more about file sharing for your group, please visit:
> > > > > > > >
> > > > > > >
> > > > > http://help.
> > > > > > > >
> > > > > > > > Regards,
> > > > > > > >
> > > > > > > > squirebug <squirebug@>
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > >
> >
>
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