Bow Roller Cracks - How worried should I be?

Tam Lin

Tam Lin

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I was talking to a fellow Centaur owner the other week and he mentioned that he had changed the bow roller on his boat because of cracks which prompted me to go and look at mine. I hope that you can see in the photos what I found! Given that the forestay is attached to the roller how worried should I be? is it

a) It's probably been like that for years and will be OK for many years to come, don't worry.

b) I had better keep an eye on it and if it gets worse, replace it.

c) it is terribly dangerous, if it failed the mast would come down, don't even think about launching!

If it is option c, could it be welded or would replacement be better?

View attachment 47530 View attachment 47531
 
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I'd do none of the things you're considering (except keeping an eye on it which you need to do for everything). Just drill a small hole at the end of the crack - to prevent it propagating further and then watch it.
I presume there is no apparent cracking around the forestay tang.
 
Tam Lin said:
I was talking to a fellow Centaur owner the other week and he mentioned that he had changed the bow roller on his boat because of cracks which prompted me to go and look at mine. I hope that you can see in the photos what I found! Given that the forestay is attached to the roller how worried should I be? is it

a) It's probably been like that for years and will be OK for many years to come, don't worry.

b) I had better keep an eye on it and if it gets worse, replace it.

c) it is terribly dangerous, if it failed the mast would come down, don't even think about launching!

If it is option c, could it be welded or would replacement be better?

View attachment 47530 View attachment 47531
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do you really mean that the forestay is attached to the roller whose bolt head is shown on the photo. In other words that the cracks are between the point where the forestay is attached and the points where the bow fitting is bolted to the hull. Surely the forestay is attached to the stainless steel tang we can see, and therefore is independant of the fitting with the cracks in it. Its impossible to tell from the photos.

the question you need to ask yourself is " is the upward pull of the forestay trying to open up the cracks or are they outside the line of pull of the forestay?"

what metal is the fitting made from? It looks like stainless in which case it can be welded
 
U
birdseye said:
do you really mean that the forestay is attached to the roller whose bolt head is shown on the photo. In other words that the cracks are between the point where the forestay is attached and the points where the bow fitting is bolted to the hull. Surely the forestay is attached to the stainless steel tang we can see, and therefore is independant of the fitting with the cracks in it. Its impossible to tell from the photos.

the question you need to ask yourself is " is the upward pull of the forestay trying to open up the cracks or are they outside the line of pull of the forestay?"

what metal is the fitting made from? It looks like stainless in which case it can be welded
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The forestay fits directly onto the roller. You can just see the bottom of it looking black at the top of the first photo and an alternative hole where it fits. I believe it is stainless. The force of the forestay is trying to open the crack.
 
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Tam Lin said:
U

The forestay fits directly onto the roller. You can just see the bottom of it looking black at the top of the first photo and an alternative hole where it fits in the second photo. I believe it is stainless. The force of the forestay is trying to open the crack.
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Should the forestay actually be attached that way, or has someone altered it? You need someone with a similar boat to show how theirs is attached. My own view is that the forestay should attach to the stainless tang.
 
Replace it!

Stemhead_CR.jpg
.. http://www.westerly-yachts.co.uk/product_info.php?products_id=169

Replace it with a double roller one while you are at it

http://www.westerly-yachts.co.uk/product_info.php?products_id=170
 
I'd be pretty worried if it was mine. How difficult is the whole assembly to take off the boat? I'd probably be looking at welding a couple of triangular gussets from the underside and down to the stainless trap that looks like it gos down the stem.
 
Norman_E said:
Should the forestay actually be attached that way, or has someone altered it? You need someone with a similar boat to show how theirs is attached. My own view is that the forestay should attach to the stainless tang.
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I think it is supposed to be like that. If you look at the photo that VicS put up you can see a row of holes along the top where the forestay fits.
I would probably replace it with a double roller while I was at it. I was told that it is difficult but not impossible to get to the bolts but with all the other work being done on the boat I was hoping not to have to do that job.
 
Tam Lin said:
The forestay fits directly onto the roller. You can just see the bottom of it looking black at the top of the first photo and an alternative hole where it fits. I believe it is stainless. The force of the forestay is trying to open the crack.
Click to expand...
In that case, I'd be getting it sorted as a matter of urgency.... the cost of a repair or a new stemhead fitting are a LOT less than having to replace the rig when it falls down!
 
The forestay fits to one of the holes on the centre web behind the actual roller. Personally I would get it re-welded which shouldn't really cost more than about £30. If you've got the money then replace it with a double roller.
 
I would consiser making up an L shaped bracket to doube up over the cracked area. ie from the bolt holding the forestay down to one or 2 of the bolts holding down the roller fitting. This may releive the loads on the crack but will also make a back up if the roller lets go. ie reducing tension on forestay but not letting it go.
The advantage of this idea is that only one or 2 of the bots through the deck need be removed. I gather access to the bottom of the bolts may be difficult. So perhaps that shuld be the first job to see what access is like. good luck olewill
 
The cracks are opening radially suggesting the roller section is lifting away and upward, and the only significant force causing this is the forestay.

As the cracks progress the remaining metal has to take the load, plus the stress raiser will be becoming more concentrated. Fatigue failure generally follows this pattern, with the final failure being a wrench of a still substantial piece of the metal.

Probably won't fail catastrophically in normal use, but would you want to get caught out in a blow knowing a hard gust could overload the fitting.

Therefore if this were mine it would be off for a decent weld repair or a new fitting.
 
Replace. This winter. Be thankful you spotted it before it got any worse.

If it was just a failed weld, then re-welding would be a repair that i have had done myself on a W22.But the crack isa fatigue failre and will one day let go - suddenly. Stainless is notorious for sudden fatigue failure. drillinga hole at the top end of the crack maight stop it prgresing for a while, but the metal beyond the crack will have stressed and distorted.

Think about this scenario: caught out in a really bad blow, with the boat pounding heavily, and the mast pumping vigorously, applying huge snatch loads to the rig. Do you REALLY want to be wondering about a possible weakness in a key component? Sods law says it will fail at the worst possible moment anyway, when there is no sea room to get things back under control, and major rig failure becomes a life threatening RNLI 'lives saved' statistic. If you are lucky. Guaranteed to be the worst possible moment.

I've twice been on boats that suffered forestay failure in 60 years sailing: both times, prompt action by helm and crew prevented the mast coming down- just! But both times we really needed quite a lot more searoom than we had while we got things under control, and things were made a great deal more difficult as we tried to keep ourselves out of more trouble. On both occasions it meant an abrupt end to the planned holiday cruise.

Get it sorted. Properly. Lifes short enough as it is!
 
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Your bow roller/forestay fitting is not as supplied with the boat when new: someone has modified the setup substantially. If remade or properly rewelded the setup might even be stronger than the original fitting, but as it is it looks like it's heading for catastrophic failure. The failure could be in 24 hours or 24 years time, but going that way it is.
 
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