I have a 460 Mast, and am in the market for a new 5.3m, most of which now use a 430cm mast. Do 5.3's rig up OK on a 460 mast? Is it worth thinking about cutting down my 460cm?
I just don't really feel like buying a new mast.
I also use the 460 for my 6.6m...
Dan Freene
Sure Willy.. PVA glue from the local kindy should do the trick eh.. just wrap a layer of newspaper around it, glue it and go sailing. Don't even need to let it dry first.
Dan, no, don't think about cutting the mast down. Masts 'bend' by a certain amount under the same loading, and different length masts are 'bendy' by different amounts. If you shorten a 460 by chopping 30cm off the top, you will have a mast that is much stiffer than the sail was designed for. The sail will not work as intended.
The basic bend measurement is called IMCS. IMCS is a way to measure the deflection of the mast under a standard loading, and then normalise that to the length of the mast so that the resulting numbers are comparible across different lengths.
A 460 mast typically has an IMCS rating around 25, while a 430 will be around 21.
Masts also have what is known as a bend curve, and the curves vary between brands. A mast with a curve that is different to the curve that the sail was designed for will again prevent the sail from performing it's best. If you go chopping bits off the mast, then the curve will be different again..
So, if you're looking at buying a new sail and want to get the best out of it, then you need to bite the bullet and get a mast that matches it.
Also be aware that masts come in two diameters - Standard Diameter (SDM) and Reduced Diameter (RDM) A new sail is likely to be designed for RDM, so you may be looking for a new extension as well..
If you're short on coin, figure out the mast you need, and keep an eye on the second hand market - you may be lucky.
So how does mix'n'matching ezzy tops and bottoms affect the imcs?
I have a 430 skinny ezzy, and need a 460. In theory i can buy the top of a 490
and use the bottom of a 430 and end up with a 460. A dude in a ws shop told me that
MR Ezzy himself recommends using a shorter bottom section.
So how does the imcs 21 bottom half and imcs 29 of the top half go with a sail intended for a imcs 25?
confused yet?
Whats even more confusing is what appears to be manufacturing differences between the same brand and models of masts. One of the English mags did a test of some of the same masts from different production runs and found there were differences in bend characteristics. Also different models from the same brand for example Pryde X6 vs X9 460s were quite different in their bend pattern. One was a constant curve, the other a flex top.
When I go home I'll see if I can find the article.
Don't forget you can buy a 30cm carbon skinny extender. North make them. This will make a 400 into a 430, a 430 into a 460, or a 460 into a 490, if my maths is correct.
Don't do it! Get a 430 or even a 400 if the manufacturer of the sail says it is a second option. (That way you can cover an even smaller sail properly as well.)
If you are really skint and absolutely have to use the mast you have: Cut off 30cm (or less of possible) from the base (Never, never the top!!) and get a longer mast extension to turn it back into a 460. A few wraps of fiberglass tape at the base to reinforce and help prevent splitting would be a good idea and make sure you use a really good boom/mast protector as the boom will now be on a possibly less reinforced part of the mast.
The 430 mast you end up with this way will be not too much different from a proper one and should work OK-ish with most sails.
But, highly recommended to get the proper mast. You will really notice the difference!
Don,t cut the mast!! It will make both of your sails handle strange especially in strong winds. Get the right mast. I,m still saving for my 4.4 and mast so I understand the pain and I hate having 3 masts for 3 sails,but love the performance.Hope this helps
Before you cut you should be sure that your extension will actually fit up your new 430 or 440 when used at its shortest. The taper might just jam around your extension.
However I wouldn't do that to a good mast. I'd try and find a second hand 430.
