Kemp In-mast Reefing Jammed

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Capt_Scarlet

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I have a share in a 34' yacht which has Kemp In-mast reefing. My co-owner has informed me that the mainsail jams when unfurling at anywhere between 1/4 and 3/4 out. It does go back in again, which is fortunate.

It has not given trouble in the past, although we haven't had this boat very long.

Any ideas what is jamming (it is not the reefing line), and how to un-jam it?

Thank you.
 
Two things have caused mine to jam:

1) halyard tension - perhaps over time it's gone a bit slack, so may need tightening. I experimented with tighter and slacker, and found the right point by trial and error.

2) mast not straight vertically = perhaps the shrouds have stretched a little. I discovered the reason because, when I opened the inspection/adjustment panels on the side of the mast, I could see that the bottom of the furling gear was pressed hard against the back of the mast.

sighting up the mast confirmed the bend, and a halyard stretched from the top of the mast to the gooseneck showed that there was a gap of about 4 inches. I've reduced this to about 1in using the lowers, but it still jams a bit. To unfurl, I wait for the boat to pitch forwards, this pushes the gear away from the back of the mast, and it rolls out bit by bit.

I'll give it some more attention over winter.
 
A common cause on our boat is the main sheet being too tight or too loose. As the sail comes out it lifts the boom up. If the kicker is on or the main sheet too tight the back edge of the sail becomes taught and folds over causing a jam. If the main sheet is too loose then there is not enough pull at the top of the sail.
 
Ah, but with our arrangement we never need to adjust the topping left. Hence as you take the sail in the boom drops slightly until the weight of the boom is taken up with the topping lift and vice versa. If you have the topping lift lift too short then as you pull out the sail with the outhaul there is only horizantal pull at the bottom of the sail and you need it further up.
 
Sounds mechanical...

[ QUOTE ]
...the mainsail jams when unfurling at anywhere between 1/4 and 3/4 out. It does go back in again, which is fortunate.

[/ QUOTE ]If it jams when unfurling, but will furl without problems, it sounds more like a mechanical problem than a tension/alignment problem. It would be worthwhile removing the furling gear and servicing it - this is an easy DIY job, and all the details are in the Selden manual (download from here if you haven't got one). Pay particular attention to the pawls and locking-ring mechanism, as a fault here could cause the problem you've described.
 
One thing not mentioned in other posts is that the car which sits on top of the boom must be free running. If you crack your balls (ouch!) they can seem to run free when no tension is on them but jam when under load. This will have exactly the effect that you describe but its not the reefing gear itself which is jamming it's the car..
 
Another thing not mentioned which has caused me problems is that the outhaul has to be held under a little tension when furling, to avoid pleats of material going into the slot. These then jam in the slot on the way out again, and can be difficult to clear.
 
[ QUOTE ]
Another thing not mentioned which has caused me problems is that the outhaul has to be held under a little tension when furling, to avoid pleats of material going into the slot. These then jam in the slot on the way out again, and can be difficult to clear.

[/ QUOTE ]

We suffer the same problem and need to keep a lot of tension in the main. We also find there is an optimum angle for the boom prior reefing/furling and adjust the topping lift to this position which is now also marked by the length of the short strop holding the boom to the backstay when moored up.
 
If you are in the market fpr a new sail , consider something with vertical battens. We had a MaxiRoach main on our Sadler and it never jammed and was able to deliver a good sail shape even when reefed down. They also do vertical battened foresails.
 
Also ( re BIG NICKs comment ) before pulling out the sail wind it in half a turn in order to remove the pleats that may have occured when last putting the sail away. We always have to do this as we have vertical battens which will otherwise jam but I understand it can help with jamed pleats as well. Good luck.
 
So is in-mast reefing really worth it compared to slab reefing? I guess if it's going to fail then it's better that the problems are with getting the sail out rather than when trying to put a reef in.

R
 
[ So is in-mast reefing really worth it compared to slab reefing?...]

For me - Yes. Once you get used to how it works best on your boat it's a dream. Makes life for the single handed sailor much easier. For single handle sailor I am refering to when you may have crew but they are not sailors and you have to do most things yourself.
 
[ QUOTE ]
[ So is in-mast reefing really worth it compared to slab reefing?...]

For me - Yes. Once you get used to how it works best on your boat it's a dream.

[/ QUOTE ]

Agreed - there is no deliberating over whether to reef or not ... it's not a big job, so you just do it.
 
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