Back Stay Going Slack

[Mitch Copper]

I own a 1980 Pearson 26 that has an ongoing problem with our back stay going slack. A year ago we did some work to the compression post but that didn't help. A local marina said the cabin top was getting soft so we did a major repair that included dropping the mast, cutting out a section of the deck an installing a steel plate to bolster the cabin top. After a half dozen sails we are losing tension again. I've tightened the turnbuckles as far as they go but still going slack. I am suspicious that our roller furling has something to do with it but I can't diagnose the problem. Any ideas out there?? I am hesitant to take it back to the boat yard for another expensive "let's give this a try" solution. Thanks for the advice.

[senormechanico]

Sounds to me like your mast is going straight down.
Look at the mast support all the way down to the keel and you will probably find the reason(s).

[wingssail]

Originally Posted by Mitch Copper

I own a 1980 Pearson 26 that has an ongoing problem with our back stay going slack. A year ago we did some work to the compression post but that didn't help. A local marina said the cabin top was getting soft so we did a major repair that included dropping the mast, cutting out a section of the deck an installing a steel plate to bolster the cabin top. After a half dozen sails we are losing tension again. I've tightened the turnbuckles as far as they go but still going slack. I am suspicious that our roller furling has something to do with it but I can't diagnose the problem. Any ideas out there?? I am hesitant to take it back to the boat yard for another expensive "let's give this a try" solution. Thanks for the advice.

My first thoughts are your forestay is getting longer or you boat is bending in the middle. Neither are good news but the forestay problem is potentially more serious and I'd look there first.

I'd get the sail off the boat and inspect the forestay top and bottom looking closely at the swedges and all the fittings. Potentially you have some broken strands or a shackle of other fitting which is deforming. You might have to replace the forestay.

I suppose the same issues could be occurring on the backstay so inspection there is in order as well.

To investigate the hull bending issue run a light weight, line from the bow pulpit to the stern pulpit and pull it tight so that there is no or very little sag. Mark the mast where the line goes past. When you notice the backstay going slack observe where that line is passing the mast. If the line itself goes slack or passes the mast higher up you know the rig is driving the whole mast system downward and potentially bending the hull. What to do about it is another question.

[tkeithlu]

This is not going to end well. The length of the slack, more than enough to take up a turnbuckle, suggests either the mast sinking or the hull folding, as being more likely than the forestay failing. Of course, if it is the forestay, you'll find that out very suddenly and it will spoil your entire day.

First, I suggest that you bring her on shore and chase down the cause before sailing her again, because something is getting ready to fail, even if it is not the forestay.

The force that's causing this flex is not great, which in itself is scary, but does allow you to chase down the problem.

Try Wingsail's line with the hull supported at the bow and stern, and again in two places near the middle.

Can you get to the masthead (roll her on grass?) to inspect for imminent failure? It should be obvious if that is the source.

Try tightening the back stay; something is going to move, whether the bottom of the mast or the hull.

Can you tighten/loosen tighten/loosen the back stay quickly enough to see what jumps? You can do that by almost tightening it, and then pushing on the side of the stay with your hand.

Lie on your back and look up the mast while someone tightens the backstay. Is the mast bending? What's happening with the shrouds?

Those would be my first attempts. Given your description, I expect the movement of something in your boat to be readily measurable.

Good luck with it. Yeah, it's time to find the problem, not to throw solutions at it.

[Antares]

Does the shroud tension change when the back stay slacks? If the shrouds are not normally slack on the leeward side, which they should not be, and don't change I would look at the fore stay including the attachment points. Also check the back stay tang and it's attachments. If the cabin top or mast step is the culprit, the shrouds also will loosen.

[Boatyarddog]

Originally Posted by Mitch Copper

I own a 1980 Pearson 26 that has an ongoing problem with our back stay going slack. A year ago we did some work to the compression post but that didn't help. A local marina said the cabin top was getting soft so we did a major repair that included dropping the mast, cutting out a section of the deck an installing a steel plate to bolster the cabin top. After a half dozen sails we are losing tension again. I've tightened the turnbuckles as far as they go but still going slack. I am suspicious that our roller furling has something to do with it but I can't diagnose the problem. Any ideas out there?? I am hesitant to take it back to the boat yard for another expensive "let's give this a try" solution. Thanks for the advice.

I don't know how many stays you have as your " back stay arrangement.
I would check those rigging wires for broken strands of wire though, this is what happens when the wires are coming apart.
Look at all swaged terminals, check for broken stays and developing cracks in the terminals.
Wire stretch will do this too.
Boatyarddog

[Boatyarddog]

Originally Posted by Mitch Copper

I own a 1980 Pearson 26 that has an ongoing problem with our back stay going slack. A year ago we did some work to the compression post but that didn't help. A local marina said the cabin top was getting soft so we did a major repair that included dropping the mast, cutting out a section of the deck an installing a steel plate to bolster the cabin top. After a half dozen sails we are losing tension again. I've tightened the turnbuckles as far as they go but still going slack. I am suspicious that our roller furling has something to do with it but I can't diagnose the problem. Any ideas out there?? I am hesitant to take it back to the boat yard for another expensive "let's give this a try" solution. Thanks for the advice.

The furler is usually an extrusion that is covering the wire so, look under there as it's the harder point to see.
If the wire is broken it will have to removed and replaced, this can be done with the mast up.
With an experienced rigger.
Boatyarddog

[zstine]

If the base of the mast is sinking, you should be able to see things bending around the step and/or base of compression post. I doubt the whole hull is bending. a 1980 Pearson should be pretty stout construction.


Some furling systems have a turnbuckle type mechanism inside the drum at the bottom of the fore stay (my Harken does). The screw in the turnbuckle may be loosening if not properly locked. If it comes all the way unscrewed, down comes the mast! I don't know the details on your furler, but I'd check the turnbuckle on the forestay is locked in place and properly adjusted.

[Mitch Copper]

Many thanks for your response. While I fear that my mast is dropping into the cabin, a problem that was already "fixed" by the boat yard, I also wonder if the repair did not return the boat to its original, new condition and there is some slight slack that needs to be taken up. Your idea of checking the front stay seems like a good first option before pursuing other more complex searches. I have an old CDI roller and can't seem to access the turnbuckle without taking off the sail and removing the roller drum. I will likely hire someone to help with this work but wondering if you have any suggestions before I get going. I assume I have to drop the sail, attach a chaser, remove the screw that fixes the drum to the forestay and then raise the drum to gain access to the turnbuckle. Doesn't sound overly complicated, even for a rookie like me, does that sound right? Thanks again.

[Mitch Copper]

Thanks, very helpful. My shrouds tend to stay tight. I think my first step is to remove the roller and check the forestay turnbuckle. I have an old CDI roller, which I think I can remove without too much complication. Appreciate your suggestion.

[Mitch Copper]

Thank you, I am going to look into this and remove the roller to check the front turnbuckle. Appreciate the insight.

[Mitch Copper]

Originally Posted by tkeithlu

This is not going to end well. The length of the slack, more than enough to take up a turnbuckle, suggests either the mast sinking or the hull folding, as being more likely than the forestay failing. Of course, if it is the forestay, you'll find that out very suddenly and it will spoil your entire day.

First, I suggest that you bring her on shore and chase down the cause before sailing her again, because something is getting ready to fail, even if it is not the forestay.

The force that's causing this flex is not great, which in itself is scary, but does allow you to chase down the problem.

Try Wingsail's line with the hull supported at the bow and stern, and again in two places near the middle.

Can you get to the masthead (roll her on grass?) to inspect for imminent failure? It should be obvious if that is the source.

Try tightening the back stay; something is going to move, whether the bottom of the mast or the hull.

Can you tighten/loosen tighten/loosen the back stay quickly enough to see what jumps? You can do that by almost tightening it, and then pushing on the side of the stay with your hand.

Lie on your back and look up the mast while someone tightens the backstay. Is the mast bending? What's happening with the shrouds?

Those would be my first attempts. Given your description, I expect the movement of something in your boat to be readily measurable.

Good luck with it. Yeah, it's time to find the problem, not to throw solutions at it.

Thanks for the great suggestions. Much appreciated.

[Mitch Copper]

Originally Posted by wingssail

My first thoughts are your forestay is getting longer or you boat is bending in the middle. Neither are good news but the forestay problem is potentially more serious and I'd look there first.

I'd get the sail off the boat and inspect the forestay top and bottom looking closely at the swedges and all the fittings. Potentially you have some broken strands or a shackle of other fitting which is deforming. You might have to replace the forestay.

I suppose the same issues could be occurring on the backstay so inspection there is in order as well.

To investigate the hull bending issue run a light weight, line from the bow pulpit to the stern pulpit and pull it tight so that there is no or very little sag. Mark the mast where the line goes past. When you notice the backstay going slack observe where that line is passing the mast. If the line itself goes slack or passes the mast higher up you know the rig is driving the whole mast system downward and potentially bending the hull. What to do about it is another question.

Thank you, I surely hope its not the hull. I am going to do due diligence on the front stay, under the roller, before I attack more serious possibilities. Appreciate the suggestion.

[Boatyarddog]

Originally Posted by Mitch Copper

Many thanks for your response. While I fear that my mast is dropping into the cabin, a problem that was already "fixed" by the boat yard, I also wonder if the repair did not return the boat to its original, new condition and there is some slight slack that needs to be taken up. Your idea of checking the front stay seems like a good first option before pursuing other more complex searches. I have an old CDI roller and can't seem to access the turnbuckle without taking off the sail and removing the roller drum. I will likely hire someone to help with this work but wondering if you have any suggestions before I get going. I assume I have to drop the sail, attach a chaser, remove the screw that fixes the drum to the forestay and then raise the drum to gain access to the turnbuckle. Doesn't sound overly complicated, even for a rookie like me, does that sound right? Thanks again.

Is there a specific issue that comes to mind when you say it's dropping at the mast step.
Are the main mast side stays loosening too, as well the "baby" or intermediate stays?
A noticeable dip in the cabin top at the mast step?
Do you think it's still a cabin top problem, and that's sinking?
Dropping your fore stay and furler foil to inspect the wire inside should be done by someone with experience, they will have to go aloft.
You cannot inspect for broken strands of wire under the foil.
Once on the ground the wire can be slid out and tangs, swaged fittings are visible.
It can then be replaced or reinstalled.
You say it's loostening up, but on this forum there are just to many variables, to be spot on.
Boatyarddog