Was having bit of an issue with mainsail pulling out of the mast track at the bottom
 
I know this sounds thick but
 
I always thought when you zapped on the outhaul pretty tight .The first line of defence 
is the clew  tie to the mast  which it is .maybe mine was bit loose but not much 
 
But when we put on the outhaul there is still pressure of the sail about a foot further up from the clew
 
I always thought the feeder fitment at the bottom of the luff groove took the strain there but when I look at the bottom of the bolt rope it is higher than the feeder when the sails up  so the strain goes onto the track and then bingo cracks it 
 
The tracks on the paragons seems to be plastic and bit thin but guess they must be carbon
 
Anybody got any thoughts  
 
 
 

 The lowest part of the mast track is the area that has the most wear, so this can open up the slot, which then leads to the sail pulling out of the track, also with it being at the bottom the track has less support, so is more likely to open up.
 
There will be a backwards pull along the length of the track, bend alters where this is focused, with more force lower down, as the outhaul and kicker have more of an effect there.  The tension in your lowers would also affect that.
 
You should be able to have the track repaired quite easily.

Anyone experienced the opposite?
The track on our Selden rig (about 6 years old) seems to be getting tighter and were munching through the heads of the sails behind the bolt rope... We've filed down any snags but any tips helpful.
 
Thanks
J 

We are running one of the last 4 Chipstows that has had very little use. We have a 9 mm plastic bolt rope on our North mains. So when we experienced the same issues I laminated 80 gm carbon tape on to the track tapering it up the mast to approx. 500 mm. At the the bottom it has, I believe 7 strips with the slot width as per the original gap. The Chipstow mast has a V track, whereas the Seldon and other makes have a U track which is less likely to spread. If the track is not plastic but carbon/glass, you can buy the tape for Easy Composites. Easy job, but the mast needs to be keyed, acetoned afterwards and when laminating, mast needs to be somewhere warm (mast up to temp and very dry) or you'll get moisture in between the laminates (as happened with Team Philipps and when the epoxy goes milky) . Hope that helps

Maybe for the Selden mast you get a new bolt rope put it but less diameter
 
I did put carbon  tape on . Think the trick is to put it right over the gap so it's on both sides then cut the slot out . Very difficult to get the tape to stick up to the edge around the  curve  
 
And the keying bit is tricky as mast is so hard and smooth 
 
But found lots of heat helped 

If it’s not a Chipstow just cut the track off and glue on a new one.

It’s pretty easy. Sharp chisel maybe a bit of heat to sometimes.

If you only cover part of the track, you will possibly generate a hard spot and when the track is put under load will crack the track. So make sure you cover all the track and taper the thickness as you go up the track. the 80 gm (25 mm) tape will give you a smoothish finish which will need final finishing
 

Hum the hard spot point.  Urghh done now 
 
Getting back to my first point though is it right the bolt rope is higher than the track feeder hence the strain is on the track 

Bolt ropes shrink with age, so expecting the track feeder to take the strain all of the time is optimistic. Once the sail is a year old I would expect it to have shrunk to the extent that the Cunningham point is now well above track feeder.
 
This is compounded by the fact that most masts now have a significant length of useable track above the lower edge of the upper band and its very easy to hoist the sail too high. This will put your boat out of class and also may well exacerbate the issue we are talking about here.
 
However I must admit I'm not sure with modern masts that the sail position is a huge issue. My Selden developed a separation issue last winter at the bottom, but I'm pretty sure this was caused my water sitting between the tube ands the track which then froze (My mast won't fit in the garage so gets stored outside.).
 
The Selden track itself is very strong. I have seen paragon tracks that have split but these were early ones and were just not strong enough in the first place. Ive not seen one split now for a number of years.

I religiously roll my sails from the bottom when taking them down so they look almost brand new and haven't shrunk   going to look at everybodys sails on Sunday  to check out where the bolt rope ends   maybe I'm hoisting wee bit high 
 
It's a paragon I have . Bit amazed how narrow the gap the mainsail goes up   plus still seems pretty thin .As I say almost like plastic 
 
Still surprised the way sailors treat their sails.   The roll from the  bottom massively extends their lives 

Why would a roll from the bottom be any different from a roll from the top with regard sail longevity?

I’ll have a look at a paragon this afternoon, we have one at LTSC 

Pretty sure releasing the track and putting a new one on is your best option 

Ok Gareth  interested in your findings
Rob if you pull a sail down then rollfrom the top with the best will in the world you will crinkle the sail   the sail never forgets them and shrinks
 
Whereas rolling from the bottom is a 2 person job and involves taking of the clew at other end of the foot 
 
if you and the crew get the foot taught them start a nice gentle roll .The sail never gets damaged. Both main and jib   ease the sails down slowly    my sails are still almost perfect after 18 months 

Ok Gareth  interested in your findings
Rob if you pull a sail down then rollfrom the top with the best will in the world you will crinkle the sail   the sail never forgets them and shrinks
 
Whereas rolling from the bottom is a 2 person job and involves taking of the clew at other end of the foot 
 
if you and the crew get the foot taught them start a nice gentle roll .The sail never gets damaged. Both main and jib   ease the sails down slowly    my sails are still almost perfect after 18 months 

Col, the bolt rope shrink is entirely different to the shrinkage dude to lack of care. Its the rope itself, not the sail, that shrinks and it doesn't seem to matter whether its proper rope or the rubber substitute.
 
Thats why the tack point slowly moves up the mast.

Ok sorry to go on but when the sail is just out of its wrapper should the bolt rope be lower than the feeder
 
Last question honest  

You should be able to comfortably tie the tack below the lowers. I think that would put the Cunningham block in the vicinity of the feeder.

Thanks Chris going to have a look tomorrow albeit looks a bit lively for yotting 

 The bolt rope does shrink, though not as much with modern ropes.  This is why it is stitched in with a length of line exposed at the bottom.  You are able to unstitch this, then hoist the sail and you will find that the rope goes further into the sail, as tension is applied.  You can then re-stitch this.
 
Have done it on older sails and it is a good way of returning the sail back towards it's original shape and making it easier to hoist as well.

In future I'm going to put another tie where the pulley is for the Cunningham to take the strain

Hi 

Looks like a glued on track. A heat gun and a sharp chisel used with extreme care should separate the track from the mast easily enough.

You can buy new carbon mast track from Allspars 

I think its worth pointing out that the track is an integral part of the overall stiffness of your mast. 
If you use a different track you will change the bend characteristics of the spar. Obviously 6 inches at the bottom won't make a huge difference, but I'd never use a different track section unless left with no option.
 
Getting the track off - cut with a hacksaw down the track towards the mast tube being very careful in the last few millimetres. One done take a cold chisel, place it on the glue join and with a decent sized hammer hit it - HARD.  This will shock the track away from the mast and will cause minimal - if any -  damage to the mast. I wouldn't use heat, there is too much chance of getting it wrong, even on an autoclaved mast tube.

Thanks everyone
 
Need to have a wee think
 
Plenty of time on the train to Scotland his weekend to watch the Scots start their victory march to the 6 nations title 

Chris M

Heat is fine as long as you stay under 80 degrees. Ie use a good heat gun not a gas blow torch.

Heat is fine in experienced hands - but its very easy to get wrong and the consequences are not good :) 

Its not all to do with the sail at that height, the track wall thickness is marginal to say the least, cut the bottom foot of mine off and replaced it with a section of australian b14 track from barnsie....turned out to be the spinny poles hitting the track when gybing ....didnt have an issue after that