The use of spreadsheets. You will probably think of this yourself.

When you are ready to make the spars and the sail, there are an awful lot of numbers that all need to be multiplied by  .9848 or whatever your final scale factor becomes. Easy to get a mistake. 

I haven’t learnt how to use my CAD progam properly yet, but when I had to apply a scale factor across a whole set of dimensions (as when scaling Slieve’s Amiina sail drawing with its original dimensions) I found it easy to put all the dimensions into an excell spread sheet.

Once done, apply a scale factor across all of them instantly.

[Edit: You put the scale factor into your spread sheet at a cell address, say, A3B4 then when you refer to it throughout the rest of the spread sheet, you refer to it not as the relative address A3B4 but as an "absolute address" which you write as $A3$B4.

After that you have a real working spreadsheet. Your scale factor is now a variable - you can change the value of $A3$B4 - or whatever the cell address is - and instantly get a whole new set of scaled dimensions.]

Also, if you want to try what it looks like a little larger or a little smaller on your drawing, then you are all set up to instantly get a new set of dimensions. As a bonus, the (scale factor)**2 follows instantly too, so you can keep an eye on the sail area.

In fact, I found it quite interesting to start with sail area and then inverse the maths,  to find the desired scale facter.

(Great thread. Its interesting to follow the thinking of these two designers.)

Paul.
I can of course find all the measurements, but they don’t pop up by themselves, so I leave that job to you (..better that you make the errors...)

This is how you do it:

·         Look up my page: https://junkrigassociation.org/arne/

·         Up to the left you find ‘the book’  -  The Cambered Panel Junk Rig.

·         Open (or better download) Chapter 4 and read it carefully.

·         Then print out Sheet 1 and 2 of the Master Sailplan with AR= 1.80

Now you need a calculator. The AR=1.80 sail I drew for you, has only been scaled down a bit from that master plan.
The scale factor is F=0.9848.
Multiply all the measurements on the master sailplan with that factor and write the found numbers onto the printed out sheets. I have double- and triple-checked those numbers, so they are quite reliable. Double-check your own calculations to be sure.

For quick and rough checks of the measurement of your boat, just print it out. I have added a metre-scale to the right which you can use.

Cheers,
Arne

Sorry, I was away checking the prices on a big winch ;-)

Arne,

You hit the nail on the head. I'm a bit saturated with ideas now. It'll take a few days I guess to come up with a decision, but I do like that monster sail for light conditions...

Could you make a copy with the measurements in?

I owe you a dinner next time I'm in Stavanger,

Wait , Make that a snack!

Last time in Stavanger, I nearly had to sell my car to pay for the hotel, food and bar bill ;-)

David, Don't scare me ;-) I'm hoping to not need the bottom panel (or 2) all the time. But It'll sure be nice in calm winds. Regards space available in 23'. Yes it was too tight until I decided to ditch half the v-berth.and the head. They'll be cut back (for'ard) It's only a sea going galley and the head is a portapotti.

I'll try to draw it out in coming days, but don't expect drawings like you and Arne okay.

Don't mock the artistically afflicted ;-)

I still have a ton of questions about mast dimensions and rudders etc.

But best I give you a break though first. ;-)

I'll think this whole thing through and ask your further advice later if that's ok...

Once again, many thanks to all contributors...

Whew, that'll take some handling on a 23ft boat! I hope you're built like a rugby second row forward, Paul. I thought the 29m² had got quite near to being OTT, but this ... will certainly need effective twin rudders (which I don't have on Weaverbird but are an integral part of my SibLim design). It's not relaxed sailing for a pensioner, anyway.

OK, I think I understand the aim with the accommodation, now. It goes cockpit>>galley>>2 seaberths>> forepeak. But I don't understand how to fit it into 23ft, though I expect you've measured up and found that it will fit if the mast is that far forward.