Thread: Building the OZ PD Racer - now renamed the OzRacer

Originally Posted by woodeneye

Technically it's a bridle when the block is not allowed to travel, but no matter, just tie a loop into the middle of the traveller/bridle (a bowline works best) and fix your block to that.

OK, so the "traveller" line is there just to put the block in a location where it does not interfere with steering.

Thank you!

Hi Raaka,

That is true of the sprit boomed rig (triangular sail). Because the sprit is inside the edges of the sail as soon as the snotter is tensioned the sail cannot twist much. So the sheet just pulls the sail in and out - not dowward. So the bridle is the best system

But with the lug sail (4 sided) the block should slide on the traveller and the traveller needs to be much tighter. We all talk a lot about how tight the downhaul has to be - this is to control the twist. The only time you have light tension in the downhaul is when the wind is very light. As soon as you have reliable speed the downhaul must be tight. And for stronger winds when the sail has too much power it has to be brutally tight.

The sprit boomed rig is the best sail for controlling twist with no extra blocks and pulleys beyond the basic
The lug rigged sail is second best if the downhaul is tight and non stretch rope is used for the halyard.
Modern rigs are better still - but at the cost of lots of bits and pieces.

The balance lug rig has less twist control than the sprit boomed rig - it is only the second best rig for . So upwind in particular you can remove as much of the remaining twist as you want by allowing the mainsheet to slide on the traveller so it is underneath the boom. Then any tension at all will start removing twist from the sail.

(I wrote this reply before but it seems to have disappeared)

MIK

Originally Posted by Boatmik

(I wrote this reply before but it seems to have disappeared)

MIK

This was happening to me with my blog so I now use Windows Live Writer which saves a local copy for you until you know your post is safely published. Is there something similar you can use for forum posting I wonder?

I wonder what would happen if one put the sheet block on the tiller - above the pintle-gudgeon pivot, where it should be stationary, or almost.

Originally Posted by Raaka

I wonder what would happen if one put the sheet block on the tiller - above the pintle-gudgeon pivot, where it should be stationary, or almost.

Howdy!

The advantage of the bridle is that it moves the sheeting point up to not far below the boom. This means that when the boom is sheeted so the boom is at 10 degrees to the centreline (minimum angle for sailing upwind) the sheet will be leading more horizontally to the top of the bridle. This reduces the load on the sheet - and your hand - because you are not having to pull the boom down to exert the sideways force you need to hold the boom.

Final reason - two holes in the gunwale five feet of rope and a pulley - and you need the pulley anyhow. Can't get cheaper, simpler or lighter than that.

It is much better with a high bridle than a low pin head. Also with a continous pin ... it might pull it out and you can't set up your mainsheet unless the rudder is in place - also with the low clearance between the rudder blade and the pin when the rudder is up slightly there is a narrow gap the mainsheet can get trapped in. It's- it is better to keep the systems separate so if one breaks the other is still working Not that anything will break - these boats are very strong despite their light weight.

For something slightly different from what you are proposing that you see sometimes ...

There is an old method of leading the sheet to top of the rudder - it was used on boats with mizzens where the rudder was shallow and long out from the transom. the idea was that you could steer to tack and the mizzen would be automatically backwinded to help the boat point up into the wind.


Thames Sailing Barge Racing - Topsail Charters

I'm not sure if it even works with a 300 ton capacity Thames Sailing barge - but it certainly doesn't work on small boats where

1/ the backwind of the mizzen just stops the boat - the best solution for back tacking is practice and if the boat is still poor then a deeper rudder blade is needed (there are lots of boats out there with inadequate rudders and centreboards - no problems with the OZ
2/ you can feel the pull of the sheet through the tiller so you have no idea whether the boat has windward helm or lee helm - so it is difficult to tune the boat for going upwind - and it gives the tiller a big pull when going downwind - at a time the tiller should be pretty neutral on most boats.

MIK

I am having trouble figuring out the snotter of the sprit rig. Is there an explanation anywhere, with a drawing preferably? I have looked at OzRacer Rigging Guide - formerly Oz PDRacer - a set on Flickr, but unfortunately, the photos are not enough for me.

I think there has to be a block/pulley on the mast somewhere, to take a line from the forward end of the boom. Said line would then go down to a clam cleat on the mast, close to the deck. But where should the block be put? Like, above or below the boom?

Hi Raaka,

It is a nice question so I will add a new thread so the same answer is there for future readers.

https://www.woodworkforums.com/f169/s...0/#post1664942

MIK

Dear Mike

I was wandering did anyone try to put a smaller sail on OZ racer? In my experience 8m2 (original) sail is too big for kids age 8-12.
So I was wandering what kind of (secondary) sail, mast etc. that would be used for teaching kids to sail could I make to use with my racer?
Perhaps the solution would be to add reef point to my existing sail but then Im still left with tall mast and long boom.

What do you think?

Greetings, Peter

While a reef would work very well, I think a dedicated smaller sail would be best for the kiddies. My favourite is a modified sprit like this one, which is 58 sq ft, although I cannot claim any sort of experience with them. This type of rig even appeared on Moths in the 80's and in fact was used on an early foiling scow.

A windsurfer storm sail could be adapted quite nicely if you could find one.

spritduck.jpg

Originally Posted by koala

Dear Mike

I was wandering did anyone try to put a smaller sail on OZ racer? In my experience 8m2 (original) sail is too big for kids age 8-12.
So I was wandering what kind of (secondary) sail, mast etc. that would be used for teaching kids to sail could I make to use with my racer?
Perhaps the solution would be to add reef point to my existing sail but then Im still left with tall mast and long boom.

What do you think?

Greetings, Peter

Yes ... that was planned in the early stages. Basically a sail can be shorter on the mast but keep the same length along the boom.

The other way is to make up a lug sail which can be reefed or even a lugsail the size of the fully reefed sail.

MIK

Originally Posted by koala

I was wandering did anyone try to put a smaller sail on OZ racer? In my experience 8m2 (original) sail is too big for kids age 8-12.
So I was wandering what kind of (secondary) sail, mast etc. that would be used for teaching kids to sail could I make to use with my racer?

I'm just back from the first outing with my OZRacer, and the sail used was 3m2 - the square sprit sail from a V10 dinghy (Bateau.com - boat plans online since 1993). I did make the 8m2 polytarp sail and the corresponding spars, but they seemed overkill for a first splash.

Carrying two adults, the boat moved very nicely with the small sail. I was quite happy. I might never use the big rig. I shall never race, anyhow.

Try the bigger sail in light or moderate winds. It is so easy to chop and change between sails anyhow.

You'll always pick up more information from trying different things That's kindof the point of the boat ... that it is not so precious that builders won't try different things.

MIK

As noted above, the first sail was a happy event. Two points, though...

1) The tiller extension, built according to the plans, was useless with two people aboard and just kept getting in the way, dangle as it did from the tiller's forward end. It really needs to be fastened somewhere when not in use.

2) The daggerboard kept popping up. A shock cord seems an obvious solution, but what would be a clever way of fastening it? This is a Recreational Vessel with the daggerboard inside the port tank.

Originally Posted by Raaka

As noted above, the first sail was a happy event. Two points, though...

1) The tiller extension, built according to the plans, was useless with two people aboard and just kept getting in the way, dangle as it did from the tiller's forward end. It really needs to be fastened somewhere when not in use.

2) The daggerboard kept popping up. A shock cord seems an obvious solution, but what would be a clever way of fastening it? This is a Recreational Vessel with the daggerboard inside the port tank.

For the tiller extension you could secure it to the tiller with a bungie (Aus speak for shock cord) loop when not required.

A bungie cord with a plastic clip attached to an eye just forward of the case is also a possible solution for your RV. This creates some tension and prevents the board popping up. However, you may find the cord and the eye gets in the way, so alternatively you could make a wedge with some rubber foam and insert this into the case behind the daggerboard so that it pushes the board forward. Secure it with a thin cord to the board handle so it doesn't get lost.