Conrad
Well-Known Member
On purchasing my boat I had the pleasure of erecting my mast for the first time, I am not sure if I have it tensioned right are there any tips as to how this should be done?
Mast erection and shroud tensioning
- Thread starter Conrad
- Start date
Bilgediver
Well-Known Member
are there any tips as to how this should be done?
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Could write a book on this and still leave something out. To really give you sensible advice it might help if you tell us more about the boat , is it fractional or full and how many spreaders.
Some elderly boats don t like excessive tension as the chain plates are just deck mounted and there is a risk of deflecting the deck.
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Could write a book on this and still leave something out. To really give you sensible advice it might help if you tell us more about the boat , is it fractional or full and how many spreaders.
Some elderly boats don t like excessive tension as the chain plates are just deck mounted and there is a risk of deflecting the deck.
exfinnsailor
Well-Known Member
All are different .. Check with the owners association .. the builder or mast manufacturer .. you normally use a rig tension guage but don't just wind up the tension on or something expensive will give ..
VicS
Well-Known Member
Much depends on the design of the rig. Masthead or fractional, number of spreaders, angle by which spreaders are swept back etc etc.
If you look at another current thread on "Rigging set up" at http://www.ybw.com/forums/showflat.php/Cat/0/Number/1807273/an/0/page/0#1807273 you will find that i have posted links to The Selden "Hints and advice" manual.
Although it is primarily an instruction manual for Selden masts much of its content is of a general nature and you should find plenty of info in there that you can apply to your own rigging.
In particular I would draw your attention to a method described for adjusting rigging tension based on % elongation. If you have a hot racing machine then maybe that will not be good enough but if you just have an ordinary small boat for pottering and gentle cruising that will be adequate. There is, IIRC, an even more basic method of assessing the tension of a masthead rig based on sailing to windward in a particular wind strength and noting the point at which the leeward rigging just goes slack.
If you look at another current thread on "Rigging set up" at http://www.ybw.com/forums/showflat.php/Cat/0/Number/1807273/an/0/page/0#1807273 you will find that i have posted links to The Selden "Hints and advice" manual.
Although it is primarily an instruction manual for Selden masts much of its content is of a general nature and you should find plenty of info in there that you can apply to your own rigging.
In particular I would draw your attention to a method described for adjusting rigging tension based on % elongation. If you have a hot racing machine then maybe that will not be good enough but if you just have an ordinary small boat for pottering and gentle cruising that will be adequate. There is, IIRC, an even more basic method of assessing the tension of a masthead rig based on sailing to windward in a particular wind strength and noting the point at which the leeward rigging just goes slack.
bobgoode
Well-Known Member
Mast falls down...not enough tension.
Boat bends in the middle...too much tension.
Boat bends in the middle...too much tension.
geoffatstanpit
Well-Known Member
I once did my rig up as tight as the rig tension thing suggested I should. It felt much too tight to me and I wound up slacking it all off a turn or two - it felt much more "comfortable". So I now do it up till it bongs rather than pings. A surprisingly sensitive indicator!
VicS
Well-Known Member
[ QUOTE ]
I once did my rig up as tight as the rig tension thing suggested I should
[/ QUOTE ] Somewhere in that Seden manual you will find the suggestion that the rigging tension is correct if the leeward rigging just starts to go slack at 15 to 20 degrees of heel if sailed close hauled in a force 3.
Provided the rigging is not adjusted to the point that it does not slack then the loads imposed are those from the wind in the sails, not the initial tensioning.
Certain fractional rigs are excluded from this rule of thumb though.
Pings and bongs may well be useful but really only after setting it correctly and learning the "correct " pitch. Not very useful though to the tone deaf who cant distinguish between a V sharp and bl**dy flat.
I once did my rig up as tight as the rig tension thing suggested I should
[/ QUOTE ] Somewhere in that Seden manual you will find the suggestion that the rigging tension is correct if the leeward rigging just starts to go slack at 15 to 20 degrees of heel if sailed close hauled in a force 3.
Provided the rigging is not adjusted to the point that it does not slack then the loads imposed are those from the wind in the sails, not the initial tensioning.
Certain fractional rigs are excluded from this rule of thumb though.
Pings and bongs may well be useful but really only after setting it correctly and learning the "correct " pitch. Not very useful though to the tone deaf who cant distinguish between a V sharp and bl**dy flat.
Conrad
Well-Known Member
Thanks for the tips, my boat Cabaret (moored at Gravesend) is a Diamond 2 which apparantly is the fore runner to the Halcyon 27. It is a 26'8" GRP made in 1964 designed by Alan Buchannon it is a long keel with a fairly standard sail set up. On the mast she has one set of spreaders with one shroud all the way to the top and two half way (each side), there is one forestay with the option for connecting a second for the storm jib, at the back there are two shrouds one to either side
smth448
Well-Known Member
Given that your mast is fairly simple it should be straightforward to set up. Your boat was built in an era before rigs were wound up bar tight so don't overdo the tension.
Put the mast up and attach the forestay, backstay and cap shrouds to stop it falling down again.
1. Set the mast rake using the forestay and backstay. I would suggest vertical as a good starting point. The backstay and forestay should be tight to stop the forestay sagging.
2. Once happy with that pull a tape up the mast on the main halyard and measure distance to the gunwhale on each side. Adjust the cap shrouds so both measurements are the same.
3. The mast is now vertical
4. Tighten the cap shrouds equally on each side until they are as tight as you want. Don't go berserk here. You want them snug, not bar tight. You can adjust them further once sailing if you are keen enough. If you do them too tight at this stage you will put a compression bend in the mast as the lowers will be loose.
5. Tighten the lowers in pairs so that the mast stays straight. Sight up the mast track to check for straightness. Take care here as you could end up with a mast that looks like a dogs hind leg.
6. Once finished go siling in a gentle breeze (f3). The mast should stay straight and the leeward shrouds should just slacken as mentioned earlier in the thread. If they go very slack then you need to tighten the rig up.
This can be done while sailing but you need to take care. tighten the leeward shrouds by one turn and then tack. Tighten the new leeward shrouds by one turn. repeat until satisfied.
Be careful as you could overtighten the rig.
Once you are happy with it put the split pins in the bottlescrews and cover with tape.
Hope this helps.
Put the mast up and attach the forestay, backstay and cap shrouds to stop it falling down again.
1. Set the mast rake using the forestay and backstay. I would suggest vertical as a good starting point. The backstay and forestay should be tight to stop the forestay sagging.
2. Once happy with that pull a tape up the mast on the main halyard and measure distance to the gunwhale on each side. Adjust the cap shrouds so both measurements are the same.
3. The mast is now vertical
4. Tighten the cap shrouds equally on each side until they are as tight as you want. Don't go berserk here. You want them snug, not bar tight. You can adjust them further once sailing if you are keen enough. If you do them too tight at this stage you will put a compression bend in the mast as the lowers will be loose.
5. Tighten the lowers in pairs so that the mast stays straight. Sight up the mast track to check for straightness. Take care here as you could end up with a mast that looks like a dogs hind leg.
6. Once finished go siling in a gentle breeze (f3). The mast should stay straight and the leeward shrouds should just slacken as mentioned earlier in the thread. If they go very slack then you need to tighten the rig up.
This can be done while sailing but you need to take care. tighten the leeward shrouds by one turn and then tack. Tighten the new leeward shrouds by one turn. repeat until satisfied.
Be careful as you could overtighten the rig.
Once you are happy with it put the split pins in the bottlescrews and cover with tape.
Hope this helps.
VicS
Well-Known Member
[ QUOTE ]
moored at Gravesend
[/ QUOTE ] I used to work in Gravesend. office and laboratory overlooking the Canal basin and the sailing club. Building now converted to flats I believe.
At least you have a pretty conventional rig. Forestay, cap shrouds, fore and aft lower shrouds and twin backstays (twin backstays because you have a transom/keel hung rudder)
Basically you can set it up as described in the Selden manual for a masthead rig with a bit of extra tension in the forward lowers to give bit of bend to the mast if possible.
If you use the % elongation method to set the tension be a bit gentle if the rigging is on the heavy side for the boat or you could overdo it.
I don't know if the mast should be raked aft, just a little perhaps but set it up vertical in the athwart-ships plane by measuring down to the gunwale either side with a halyard.
If any of your rigging is attached to inverted U bolts (it is in the Halcyon 27 I'm looking at pictures of) be suspicious if there are any rust stains around them or any evidence of water leaking in via them. Crevice corrosion can occur where they pass through the decks. Nearly lost the mast of a Westerly a few years ago when one failed. A second failed as we tried to remove it for inspection! I would not want to panic you into removing them for inspection , but....
moored at Gravesend
[/ QUOTE ] I used to work in Gravesend. office and laboratory overlooking the Canal basin and the sailing club. Building now converted to flats I believe.
At least you have a pretty conventional rig. Forestay, cap shrouds, fore and aft lower shrouds and twin backstays (twin backstays because you have a transom/keel hung rudder)
Basically you can set it up as described in the Selden manual for a masthead rig with a bit of extra tension in the forward lowers to give bit of bend to the mast if possible.
If you use the % elongation method to set the tension be a bit gentle if the rigging is on the heavy side for the boat or you could overdo it.
I don't know if the mast should be raked aft, just a little perhaps but set it up vertical in the athwart-ships plane by measuring down to the gunwale either side with a halyard.
If any of your rigging is attached to inverted U bolts (it is in the Halcyon 27 I'm looking at pictures of) be suspicious if there are any rust stains around them or any evidence of water leaking in via them. Crevice corrosion can occur where they pass through the decks. Nearly lost the mast of a Westerly a few years ago when one failed. A second failed as we tried to remove it for inspection! I would not want to panic you into removing them for inspection , but....
Conrad
Well-Known Member
Thanks all,
I feel a lot more comfortable now especially having just climbed up it to reinstate the spinaker halyard that had to be unceremoniously cut last season.
I feel a lot more comfortable now especially having just climbed up it to reinstate the spinaker halyard that had to be unceremoniously cut last season.