I have a 1998 hunter 450 passage. I believe it has Z spars mast and mast step. I have just noticed that under stress the rear of the mast will twist up to 0.5 cm laterally either to left or right across the mast step base. Is this normal or has the mast step base been damaged internally or is there some other fault Mike
Mast movement
- Thread starter Beluga Free
- Start date
Well the tabernacle (the fixture that attaches the mast to the deck) (mast step is usually referred to as a deck step or keel step BTW) should fit tightly around the bottom end of the mast to prevent all movement or twist. I'm pretty sure if it is twisting by 1/2 cm either you have the wrong tabernacle for that mast or the tabernacle is loose on the deck. Both are something that needs looking into. Got a picture?
Can't really tell from the wording, but I think B. Free means mast BEND. That is a function of lower shroud tension. Directions to temper this are given in any discussion of mast (rig) tuning. If the O.P did in fact mean "twist" - never mind!
No it is not mast bend.The base of the mast will twist across the face of the base plate up to 0.5 cms,if you pull on the vertical shroud.
Obviously I won't be able to see this, but still interested in your situation. Assuming you have the B&R rig and the upper and lower shrouds terminate aft of the mast. Also assuming then that pulling on the shroud, as you say, causes the entire mast to twist - i.e. pulling aft from one spreader and the other not tight enough to resist the torquing motion. So, seems this is still a function of rig TUNING, primarily shroud tension.
Again, I'm just thinking out loud, so don't put too much stock in this. Just trying to figure it out along with you. Do you have just one set of lower shrouds? And, do they terminate at the same chainplate as the upper shrouds? Assuming, also, that this is a double spreader rig with intermediate shrouds. ???
Again, I'm just thinking out loud, so don't put too much stock in this. Just trying to figure it out along with you. Do you have just one set of lower shrouds? And, do they terminate at the same chainplate as the upper shrouds? Assuming, also, that this is a double spreader rig with intermediate shrouds. ???
It would seem you possibly have a Z Spars mast. If this is the case then this is their web page:- http://www.zsparsuk.com/secold.htm.
You should measure the dimensions of your mast to verify the section used and I have always found the Z Spars people most helpful - at least those in the UK are so I see no reason why this should not be a company wide culture and a phone call to them should indicate the way forwards.
If the mast section is their Z1001, as listed for your size of boat, then this is the Z Spar page you need:- http://www.zsparsuk.com/z1001.htm.
If not, at least you will see what should be bolted down on the deck and whether it is likely allow any rotation of the mast; but my gut feel is that only the slightest engineering clearance should exist between mast and step, just sufficient to allow the mast to be lowered on to its step whilst it is hanging from a crane, and item 3222 is likely to be a close fit, whereas either item 3138 or 3383 is likely to permit the amount of movement you see.
Also I would try to determine whether your mast is the original, or if it has been changed to one, either by an alternative maker or a replacement of the original mast from the same manufacturer. Maybe the mast is a different section to the original but the mast step might not have been changed at the same time.
I guess the acid test is "does it move whilst sailing?"
You should measure the dimensions of your mast to verify the section used and I have always found the Z Spars people most helpful - at least those in the UK are so I see no reason why this should not be a company wide culture and a phone call to them should indicate the way forwards.
If the mast section is their Z1001, as listed for your size of boat, then this is the Z Spar page you need:- http://www.zsparsuk.com/z1001.htm.
If not, at least you will see what should be bolted down on the deck and whether it is likely allow any rotation of the mast; but my gut feel is that only the slightest engineering clearance should exist between mast and step, just sufficient to allow the mast to be lowered on to its step whilst it is hanging from a crane, and item 3222 is likely to be a close fit, whereas either item 3138 or 3383 is likely to permit the amount of movement you see.
Also I would try to determine whether your mast is the original, or if it has been changed to one, either by an alternative maker or a replacement of the original mast from the same manufacturer. Maybe the mast is a different section to the original but the mast step might not have been changed at the same time.
I guess the acid test is "does it move whilst sailing?"
It would seem you possibly have a Z Spars mast. If this is the case then this is their web page:- http://www.zsparsuk.com/secold.htm.
You should measure the dimensions of your mast to verify the section used and I have always found the Z Spars people most helpful - at least those in the UK are so I see no reason why this should not be a company wide culture and a phone call to them should indicate the way forwards.
If the mast section is their Z1001, as listed for your size of boat, then this is the Z Spar page you need:- http://www.zsparsuk.com/z1001.htm.
If not, at least you will see what should be bolted down on the deck and whether it is likely allow any rotation of the mast; but my gut feel is that only the slightest engineering clearance should exist between mast and step, just sufficient to allow the mast to be lowered on to its step whilst it is hanging from a crane and item 3222 is likely to be a close fit, whereas either item 3138 or 3383 is likely to permit the amount of movement you see.
Also I would try to determine whether your mast is the original, or if it has been changed to one, either by an alternative maker or a replacement of the original mast from the same manufacturer. Maybe the mast is a different section to the original but the mast step might not have been changed at the same time.
I guess the acid test is "does it move whilst sailing?"
You should measure the dimensions of your mast to verify the section used and I have always found the Z Spars people most helpful - at least those in the UK are so I see no reason why this should not be a company wide culture and a phone call to them should indicate the way forwards.
If the mast section is their Z1001, as listed for your size of boat, then this is the Z Spar page you need:- http://www.zsparsuk.com/z1001.htm.
If not, at least you will see what should be bolted down on the deck and whether it is likely allow any rotation of the mast; but my gut feel is that only the slightest engineering clearance should exist between mast and step, just sufficient to allow the mast to be lowered on to its step whilst it is hanging from a crane and item 3222 is likely to be a close fit, whereas either item 3138 or 3383 is likely to permit the amount of movement you see.
Also I would try to determine whether your mast is the original, or if it has been changed to one, either by an alternative maker or a replacement of the original mast from the same manufacturer. Maybe the mast is a different section to the original but the mast step might not have been changed at the same time.
I guess the acid test is "does it move whilst sailing?"