PD Racer South Africa

guys a good page for the Lug sail

http://www.storerboatplans.com/GIS/GISRigging.html

lots of really good info from an experienced designer

please correct me
what I see when I look at this drawing of Michael Storer is a rig that can easily be reefed down for a child - novice sialor
easy stowable
easy to erect and to get going

 

good news
I found 2 beautiful videos that show reefed and full open
fantastic

http://www.youtube.com/watch?v=IVSo1E8tTbw&feature=related

http://www.youtube.com/watch?v=CEEBcEkp294&feature=related

 

Well this is where I am heading

my sailing/rowing dinghy, cum life raft, kids toy, party boat, attention grabber

AND and and what not else
2 beds AND another 100 kgs beer in tow

and all this for ONLY 4 SHEETS - now how cool is that

I must thank Dries for asking me to re-look at the whole PD Racer scene
this has opened a world of possibilities that wont break the bank
now I am even more happy that I built the micro so small
I always wished I had another 2 bunks, and now i've got it

AND the bonus is sailing a PDR is VERY good for an old farts "six pack"
last time I sailed a Laser I couldn't walk for a week
So Wynand if the "crew" has a litter in tow, I can shove them into the dog box

ag sies man, jy is alweer stout ne!

 

Baie dankie!

 

For me, the best is the balanced lug.

The thing about reefing a sail is that The Vertical Center of Area (VCA) changes. But the Horizontal Center of Area (HCA) changes as well.

On most triangular sails the HCA moves forward quite a bit. This plays havoc with the boat's 'balance' causing a severe lee helm. It is for this reason the leg-'o-mutton rig is generally not reefed. The tension on the snotter is increased to pull the sail flatter, so it can be feathered to decrease its drive.

With a balanced lug, the HCA moves aft very little as you reef. How much or how little depends on the length and rake of the yard and how much the sail is shortened. Generally, with a severe reef of half the sail area or greater, the HCA will move less than ten percent of the boom length aft.

Matt's rig is really what is called a 'standing lug' where the boom crosses the mast by a very small distance, if at all. That is just as easy to reef as a balanced lug, but may need a vang to keep the boom from rising, as the sheet line is let out.

By drawing diagrams, I have found that having the yard as long as the boom and raked 45 degrees from horizontal, gives the least HCA shift and the most sail area per given length of luff.

If you stick with a Bermudan rig, you will need to have a way of moving the Horizontal Center of Lateral Area (HCLA) forward, as you shorten the sail.

There are three ways you can do this:

1.) have a deep, pivoting lee board or centerboard which is raked quite far aft under full sail and is pulled to a more vertical position, as the sail is shortened (If you go with a full roach, this strategy will work well),

2.) have a dagger board that has a long enough trunk, so that it can be slid forward as the sail is shortened (You could have your dagger board side mounted and just have a rack) ( boat # 7, in the fleet used this strategy), or

3.) have the board set to balance the boat on the last reef, and put up with a strong weather helm under full sail. When your arm starts getting tired, its time to reef.

Of course, you can always split the difference. You can have the board rake or slide aft enough to balance the boat on the first reef and slide or pivot forward enough to balance on the second, leaving a lesser weather helm under full sail. This would allow a shorter pivoting board and a shorter trunk or rack for a sliding dagger board.

 

By all thats holy the powerball turned out to be 11 which I played and backed up with 1 just in case.:idea:
Made a bit of money with three numbers and the 11 powerball - just missed the other two numbers by a whisker with one count either to high and to low - close call but since I stay poor, Im still up for donations again.
Perhaps better luck next time....

 

Thanks, just what I was looking for

what percentage of the boom length would you recommend forward of the mast?

and the yard?

thanks

 

About 40% is the general consensus for the yard and you want the luff to be almost vertical to slightly raked so the boom is adjustable to your liking. Make sure you sail has a good strong bolt rope in the luff as you need to put a lot of tension on it with your downhaul to get maximum weatherlyness (I suppose that is a word).

 

A little late for the "Here is a cute duck." bid, but here is a very yachty looking one that caught my eye. I think they've proportioned the topsides very nicely for an elegant look.....for a duck.

 

that seems a lot
the pics generally seems to be 10 to 15 %
am i missing something ?

that i see ok

 

Attachment is right at 40% of the length of the head along the yard. Sorry...I must have misinterpreted what you meant

 

Hi Steve, thanks for the pic, I have been following that build, its lovely.

I imported your picture into CAD so that i could measure the area's and the distances
I am not always quite sure what the guys mean - but a good pic like your really helps a lot
the units may not be correct because I "expanded" the import until it was more or less the same size as mine on the PDR

However the percentages are correct, they remain the same regardless of the units (feet v metric)

so your sailplan is approx 19% in front of the mast
and the boom approx 21% in front of the mast

I like your sailplan it and really looks good and looks "balanced" compared to what else I have seen
the angle at 27 deg could be on the steep side, I have seen them say 45 deg
but that we could only really tell when we see videos of your boat on the water

 

Well...I have had nothing but compliments on the sail and how it sets...just beginner's luck I guess. It pulls like a freight train but it doesn't have a great deal of heeling moment as compared to a Bermudan or a Leg 'O Mutton. I got the sail from Duckworks Magazine. The angle of the yard (or actually the head of the sail) is rather arbitrary...it depend on if you want a higher aspect or lower aspect. You could go with a square sail if you so wanted but it would be rather small in length (for proper CE placement) and/or be quite tall along the luff (hard to get decent tension on the luff that way) to get decent area. This way you have something approaching a gaff with a jib except it is all in one sail...kinda. Tuck the bottom in and get the Peak up and you have a standing lug which you can then shoehorn a jib on to the front of the mast with. You would probably want the foot of the sail to be angled differently though...or the boom would be too high. You would need a longer leech.

 

Steve what I did here was to make the mast 90 deg upright
to determine CE
what i find very interesting is that your CE is kinda low above the waterline
it sure makes sense to me, dont know what the other fellas would say?

To me, your rig looks really good
love to see pics on the water

the angles are now measured from a mast that is 90 deg straight up

great stuff

 

just the link for the other fellas

steve's scow

http://www.boatdesign.net/forums/wo...on/new-thread-middle-my-scow-build-32310.html