Thread: Change of Rig

G'day Petrel
How does the boat sail with the existing rig ?
Need to know that before changing stuff.

At the very least, a profile shot with sails up & rudder & board in place to get some
idea of where current centres of effort & lateral resistance lie. If you can't drop the
board, stand it up in front of the boat, in line with its case.

Out of curiosity, the bottom looks like it is an outboard power skiff with sailing gear
added by the scouts. Does that sound about right? How well does it behave under
sail ?
cheers
AJ

Hi AJ
I think you might be right about it being an outboard power skiff, certainly the sailing gear has been cobbled together. I'll drop the centreboard in on the w/e and take some shots. Surprisingly it behaves quite nicely undersail but is very underpowered. With the existing sail (approx 96sq.ft) the boom sits up at about 20 degrees from horizontal and is short of the masthead by a little over a metre. there is no vang and the mainsheet runs through a block attached to the 2nd seat!.
Cheers
martin

it looks like it will be Ok from the profile view as a sailboat.

I don't know if you want to change the centreboard case or not. Is there a good reason?

With a centreboard case and centreboard position underwater known the rig can follow.

With shallow boats I have found you can almost ignore the rest of the boat and just plonk the rig in relation to the immersed part of the centreboard.

And how big is the centreboard? That may be an odd size too!

MIK

Hi Mik,
I'll position the centreboard for photo on the w/e and post. It wouldn't surprise me if you and others think it an odd size, it doesn't fit the box properly anyway. The inside of the box is ferral, it has epoxy protrusions that abrade the centreboard, it's made from 3mm ply and it leaks ( not badly but it does) so I'm keen to do a proper job.
Thanks
martin

I'd agree with Michael on where to place the sail plan. Figure out the new CE and place this vertically over the center of the (I'm assuming) daggerboard case. You have a small skeg and rudder with little else immersed, so you'll probably carry a slight weather helm (which is what you want).

For good all around performance, in a boat of that general shape and size, you'll want 100 to 130 sq. ft. of sail (more if you're a wild man). This will offer high teens for an SA/D and good light air ability. For a more docile sailor, drop down to 80 sq. ft. which will lower the SA/D to the upper mid teens.

As for sail dimensions, well Michael would be a better person than I, on the lug but a 15' luff on an 8' foot will offer around 120 sq. ft. and keep the CE relatively low too.

The 3mm ply for the case is not a problem. But if it leaks it has been badly put together or attached to the boat.

MIK

Attached is the position of the centreboard. Mik, the case leaks because of the attachment to the boat. I'll have to remove it to get to bottom of things, so to speak. Ideally I'd like to carry 130-140sq.ft, you can always put a reef or two in.
Thanks

Haha, it is a VJ centreboard and it looks way too far forward. I think they copied the original position in the Vee Jay without realising that this one doesn't have a bowsprit!

I would suggest moving it back ... probably .. depending on the rig you are thinking about.

Just so PAR can get excited .. here is a VJ, an older style boat for kids, designed in Sydney in 1929. Many of the skiff sailors came up through the class. If you take the group of sailors about 10 years older than me, there are a huge number of seriously good sailors (John Bertrand who took the America's Cup away was a graduate of the class). Usually kids were out if it and into the skiffs by about 16 or 17.

Had a flat cut spinnaker with a wire luff so you could sail upwind with it. You gybe the kite by throwing the spinnaker pole around the forestay and picking it up out of the water when you complete the turn. hehehe

MIK, The rig I'm thinking about is an unstayed balanced lugsail. Moving the centreboard box back is do able but I'm afraid my attempt might end up weakening the "keel" such as it is. I've been looking at Catboats and such and they seem to handle the mast well forward. Hmmm... a bowsprit might look nice, though

It won't weaken the keel ... you can just put some glass cloth over the top of it after filling the old slot up and it will be stronger than the original ... because the glass will prevent the timber from splitting.

Ok .. so just a single lug sail? The advantage of the single sail is cost and saving a lot of rigging time.

140 or 150 is a very big sail that requires quite a tall and heavy freestanding mast to hold it up.

I think the GIS sailplan of 105 would be more than adequate unless you want to go round breaking records.

MIK

I don't mind breaking records, just not the boat. Just had a quick look at the GIS. 4.73m as opposed to 5.2m, would it be fair to go 115sq/m for the sail?

Haha, you are as bad as me!!!

I always move the estimate up too.

The thing about the GIS is that the solid round mast is quite heavy to get up so we have developed a box section mast and a birdsmouth section mast to get the weight down where it is manageable.

Going that bit extra might make the mast hard to handle again.

MIIK

Ok, I wrote in for advice from those in the know, what's the point if I'm not going to take it.

The GIS rig will do fine. Now, do you think I still have to move the mast and centreboard box?

Martin

is it 17ft long exactly Can you measure.

And also an estimate of how far the bow and stern move in from the vertical full length measure.

MIK