Can excessive mast bend be the cause of my jamming in mast furling ?

affinite

affinite

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Question is as per the thread title.
I have a Moody44 with in mast furling in a Kemp mast
The furling gear is difficult to wind in or out and I have had several sail jams recently.
I just noticed that unlike most boats in our yard, my boat has a pronounced bend.
Common sense would suggest that this will not help the in mast furling to run smoothly compared to a straight mast but how do I find out how much bend and rake I should have?
 
Hi,

I have a 42 with Selden in mast furling and new Kemp sails.

Whilst we don't get sail jams, we have huge amounts of friction in the system, both winding in and out.

Pm me and let's discuss!

Tony
 
My understanding is that the mast should be dead straight if you have in mast furling. Mine is and we don't have furling problems.
 
Robih said:
My understanding is that the mast should be dead straight if you have in mast furling. Mine is and we don't have furling problems.
Click to expand...

Correct. But if the furling gear isn't serviced and lubricated regularly, it can get very sticky. Modern systems are somewhat better designed, and are easier to operate. It can also help to have the main treated with Seal'n'Glide or a similar product to reduce friction in the slot.
 
It is very important that any backstay tension is released and that the boom is set perpendicular to the mast before trying to reef on a craft with in mast reefing. Otherwise it may just jam.
 
Strathglass said:
It is very important that any backstay tension is released and that the boom is set perpendicular to the mast before trying to reef on a craft with in mast reefing. Otherwise it may just jam.
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The boom doesn't have to be perpendicular to the mast. Perhaps you're confusing in-mast with in-boom furling.
 
You definitely do not want any positive mast bend as this will cause the rolling up sail to bind against the inside of the mast. Our - admittedly quite old - 1980's - system advises a small degree of reverse bend in the mast from absolutely straight.

Set the mast straight and have the boom with a degree of upward inclination and it should roll in easily.
 
affinite said:
Question is as per the thread title.
I have a Moody44 with in mast furling in a Kemp mast
The furling gear is difficult to wind in or out and I have had several sail jams recently.
I just noticed that unlike most boats in our yard, my boat has a pronounced bend.
Common sense would suggest that this will not help the in mast furling to run smoothly compared to a straight mast but how do I find out how much bend and rake I should have?
Click to expand...

I had exactly the same boat as you and the mast was dead straight. Furling was not a problem in any winds.
 
Lessons learnt from running a large charter fleet in the Med:

Novices will have no difficulty with in mast furling, and will not have to use any "special techniques" to avoid jams, if the boats are maintained to keep to the following three rules:

(1) Straight mast (removes friction)
(2) Flat sails (baggy sails create creases which jam when unfurling)
(3) Light Halyard tension (high tension raises bearing friction, and creates luff crease which fattens the roll)

It also doesn't help if the sails are not built to specs for the furling system in use. I've seen excess weight sailcloth, stiff luff re-inforcement, Large adhesive logos back to back in the middle of the sail, leach UV strip, and a foot which has been re-inforced.
 
>(1) Straight mast (removes friction)
(2) Flat sails (baggy sails create creases which jam when unfurling)
(3) Light Halyard tension (high tension raises bearing friction, and creates luff crease which fattens the roll)

This is true but flat sails and light halyard tension is a recipe for poor sailing performance by the main which why I would never have it on a boat. Not to mention we had one jam with the sail fully out in Antigua sailing week, the boat was a 52 foot Jeanneau.
 
KellysEye said:
>(1) Straight mast (removes friction)
(2) Flat sails (baggy sails create creases which jam when unfurling)
(3) Light Halyard tension (high tension raises bearing friction, and creates luff crease which fattens the roll)

This is true but flat sails and light halyard tension is a recipe for poor sailing performance by the main which why I would never have it on a boat. Not to mention we had one jam with the sail fully out in Antigua sailing week, the boat was a 52 foot Jeanneau.
Click to expand...

If performance is your main criterion, you don't tolerate mast weight, flat sails, or sails without roach. Therefore you you don't use roller reefing - either for headsails or mainsails! And you use bigger crew . . . in numbers and weight, to make things happen quicker and to keep the boat more upright.

Rolling reefing is for those whose main criterion is ease of use, especially when short handed. If the boat is moving too slowly to its destination, I either shrug my shoulders and prepare for a night arrival, or start the engine. Or change the destination!
 
Its not difficult to ease the Halyard tension when furling and adjust for wind conditions when sailing. You can't do any thing about the sail cut but you can get the mast straight. Two out of three should help. I wouldn't personally have in mast.
KellysEye said:
>(1) Straight mast (removes friction)
(2) Flat sails (baggy sails create creases which jam when unfurling)
(3) Light Halyard tension (high tension raises bearing friction, and creates luff crease which fattens the roll)

This is true but flat sails and light halyard tension is a recipe for poor sailing performance by the main which why I would never have it on a boat. Not to mention we had one jam with the sail fully out in Antigua sailing week, the boat was a 52 foot Jeanneau.
Click to expand...
 
Last edited:
Thanks for all the advice from this thread.
Now that Im confident that Ive cracked it, I thought that an update might be order to help others ...

This Easter
I replaced the mainsail with a nice, crisp new one from Jeckells. (1 used main aka Nora Batty for sale @ £1, buyer collects from Turkey)
I raised the sail without overdoing the halyard tension
I removed and serviced the top and bottom furling gear (Nightmare !!)
I adjusted the stays to reduce the mast bend (Work in progress to get correct rig tension going forward)

So far so good.
The new sail pulls out/in with minimum drag and furls away cleanly.
The weight of cloth I chose means that the mast is full when the sail is fully furled but it doesnt seem to impair furling action

I'm looking forward to a full seasons road testing and will report back!
 
affinite said:
Thanks for all the advice from this thread.
Now that Im confident that Ive cracked it, I thought that an update might be order to help others ...
Click to expand...

Stand by for a slew of irrelevant new advice from people who don't read the thread before opening their traps :D

Pete
 
Robih said:
My understanding is that the mast should be dead straight if you have in mast furling. Mine is and we don't have furling problems.
Click to expand...

+1 mast should be straight which is why it is best to have a backstay tensioner to bend the mast only when needed.
 
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