If you buy an secondhand mainsail you should change the sail numbers on it to match the sail number of your boat. In the same way, if you buy a boat abroad you should change the national letters so they are correct, for example change "IRL" to "GBR". Probably worth marking in pencil where the bottom and top of the numbers or letters you are going to take off are, so you have a bit of a guide when you come to stick the new ones on. The old numbers or letters should pull off OK, they might leave some glue behind. It's best to be careful, and try minimise the amount of glue left behind. Pulling the number off gently, and at 180 degrees to the bit of number still stuck on (so the pulled off bit of number is over the remaining stuck on section) can help. You could also try encouraging any glue sticking to the sail at the boundary where the number is coming off, to stick to the number instead by scraping it with a knife or similar. Any remaining glue/gunk can be removed with acetone. I also find Brasso metal polish also very good for removing sticky gunk. I think the amount of exposure to UV light has a big affect on how much glue is left behind. Changing the numbers on a ten year old mainsail that had only been used at a couple of events was easy, no glue left behind. But on a similar sail that had done a lot more events, there was a lot of glue and it was a bit of a pig to get off. However, getting the old glue off is worth it as it looks much better and you don't have sticky patches left behind which will collect all manner of dirt, grass clippings, dust,.....
You can buy new letters or numbers (which must be black) from any good chandler (e.g. Pinnell & Bax) or you local sailmaker will sell you some, or you can buy a small amount of black sticky backed polyester from a local sailmaker and make your own (cheaper). If you make your own you can use the numbers or letters on another sail as a pattern. Don't forget to turn the pattern over, so you mark out the back of the pattern onto the paper on the back of the roll of sticky backed cloth.
Don't forget that the insignia goes above the national letters which go above the sail numbers. Don't place national letters or sail numbers "back to back", they need to go in separate rows with those on the starboard side of the sail uppermost. Insignias can only be placed "back to back" if the starboard side one is "reversed" so the "points" are towards the leech.
Numbers and letters have to be a minimum height of 230mm (most are 300mm, so a lot bigger), a minimum of 45mm apart and a minimum of 45mm from the edge of the sail to comply with the Racing Rules of Sailing (RRS) Appendix G. Please note that 'digital' font (where numbers are made up from straight line elements in fixed locations in a similar way to a liquid crystal display) are not permitted.
When fixing numbers or letters:
Over the years there have been many articles advising on how to improve your boat, here are a few.
Here are a few other ideas
Hull - skeg
You can fill in the hole in the skeg and you can reduce it's size to the minimum permitted in the Class rules (currently rule 1.4.10). Don't forget the keelband has to run the length of the skeg up to the transom and it has minimum dimensions which thus limits the thickness of the bottom edge of the skeg. The current issue of the Class rules can be downloaded from the ISAF website by following these instructions.
Hull - "bilge keels"
You can shape the ends of these and reduce their cross section to the minimum permitted in the Class rules (currently rule 1.4.9). As you can see from the rule, the central 915mm length has to be not less than 13mm wide and 9mm deep. Anything outside the central 915mm can be shaped as you like.
I understand this mast is based on Goldspars Flying 11 GTD5015 section. It comprises 50 mm tube with 1.5 mm walls and an internal sleeve. It has a spun conical top above the hounds.
You can simply lash a block to the daggerboard case with a bit of line running around the case under the capping. You need about 1620mm of of 3mm or 4mm line to do this.
Another simple method is to just to attach a deck clip (lacing eye) on the centre of the thwart and attach the mainsheet block to this. This position has the disadvantage of further restricting the space available for the crew between the mainsheet and the kicking strap. There is not enough room to mount a mainsheet block swivel stand up base or a mainsheet block and swivel jamb cleat in this manner. A disadvantage of this method is that the fixings are in tension, so a risk screws will pull out of the thwart. If the deck clip is bolted on (following Celia's Law), they should be fine.
A mounting block of wood etc. can be glued under the aft edge of the thwart with a glue join to the aft edge of the daggerboard case. This gives a vertical face which the deck clip can be mounted on. It's not a suitable method to mount a mainsheet block swivel stand up base or a mainsheet swivel jamb cleat.
A metal plate which extends aft of the thwart can be screwed to the top of the thwart. UK mast manufacturer Superspars sell such a mounting plate shown here on 70500 - Mega Wind (though variations in thwart design between wooden and GRP boats made it hard to standardize - they had two in stock in April 2014).
Or they can be fabricated from scratch as shown here on 70492 - The Black Pearl. Needless to say the plate needs to be strong enough to not bend under the loads imposed on it. This gives a suitable platform for any swivel fitting you might wish to use. The one above was designed by Steve Lenney to take a Harken swivel cleat and fabricated from 3mm stainless plate by a Falmouth company Fibre Fusion using a CNC water jet cutter.
A horizontal mounting platform extending aft of the thwart can be fabricated from wood etc. This is glued under the back edge of the thwart and experience shows a knee glued to the aft edge of the daggerboard case is needed.
The mainsail sheet starts near the end of the boom, or the becket of a block attached near the end of the boom. It then goes around a single block attahced to a bridle attached to the mainsail sheet attachment points on the aft transom. It then goes around a single block near the end of the main boom, through a boom sleeve or constraining loop on the main boom to a block near the centre of the main boom. It then goes to the helm's hand. Purchase is about 2.5:1
Fairly rare, but some Australian and South African boats use it. As with similar bridle systems, it allows the main boom to be brought closer to the centre line with less load on the mainsail leech than with the traditional aft mainsail sheet system. The length of the bridle determines how efficiently this system does this. A bridle which is as long as possible without going "block to block" when sailing close hauled is most efficient.
There is a 2007 advise sheet on a slightly different system, but which may help setting up the bridle.
For a very basic hull fit out, the Bell Woodworking building instructions from the 1960s may be sufficient. Details are on pages 19 (mast step), 23, 24 & 25.
For a more sophisticated and up to date fit out, read the following articles.
It's also worth checking out some of our example fit outs.
