Keith Miller
Registered Guest
I’m in the process of buying a 376 and the survey has picked up an issue with the compression post
Moody 376 Compression post issues
- Thread starter Keith Miller
- Start date
- Boat name
- MORNINGAFTER
- Berth
- Island Harbour . Cowes
- Boat type
- Moody 376
- Cruising area
- South Coast
Hi Keith, This is a well known 376 problem, the mast compression support was cast iron and it rusts. The solution is , rig down, remove joinery and replace the mast support, the bulkhead bonding needs to be checked as well. Hope this helps, not a DIY project I’m afraid, Regards, John
Keith Miller
Registered Guest
That’s very helpful John thanks very much for the information
Keith Miller
Registered Guest
Great
I’ve had a survey and the deck was okay.
Thanks a lot for your info John much appreciated
I’ve had a survey and the deck was okay.
Thanks a lot for your info John much appreciated
- MOA Position
- East Coast Captain
- Boat name
- WILD THYME
- Berth
- Suffolk Yacht Harbour
- Boat type
- Moody 425
- Cruising area
- North Sea, English Channel, Biscay
Hi,
I don't think Moody ever used cast iron for a compression post, they used a mild steel tube with mild steeel plates welded on for the top and bottom ends. It also rusts. Greater problems with the mast support system arise from the timber blocks , one on which the compression post is mounted and the other in the deck between the top of the compression post and the mast step. In both cases, water can get into them and start rot with the consequence that the timber can no ;longer bear the load and gets squashed thinner. In the case of the block in the deck. the issue often arises because the holes bored through it to pass cables below deck are not adequately sealed.
Peter.
I don't think Moody ever used cast iron for a compression post, they used a mild steel tube with mild steeel plates welded on for the top and bottom ends. It also rusts. Greater problems with the mast support system arise from the timber blocks , one on which the compression post is mounted and the other in the deck between the top of the compression post and the mast step. In both cases, water can get into them and start rot with the consequence that the timber can no ;longer bear the load and gets squashed thinner. In the case of the block in the deck. the issue often arises because the holes bored through it to pass cables below deck are not adequately sealed.
Peter.
Pavel Hort
Member
- Boat name
- SOLITAIRE OF MYLOR
- Berth
- Mylor harbour
- Boat type
- Moody 376
- Cruising area
- Cornwall
Hi,
I'm very new to Moody 376 (new owner) and one of the first issues I have spotted is the completely rotten Compression post plate
.
As I see it and correct me if I'm wrong:
1. Mast has to go down
2. A whole new compression post to be installed - fiberglassed back into the hull
3. make sense to install a new standing rigging ( 15+years) when mast is down in marina
All job to be performed by professionals, I wonder what kind of price tag I would be looking at £ to brace myself?
Anything could be done DIY to prepare it for marina and eventually save some costs?
And its only when everything else is good.
Pav.
I'm very new to Moody 376 (new owner) and one of the first issues I have spotted is the completely rotten Compression post plate
. As I see it and correct me if I'm wrong:
1. Mast has to go down
2. A whole new compression post to be installed - fiberglassed back into the hull
3. make sense to install a new standing rigging ( 15+years) when mast is down in marina
All job to be performed by professionals, I wonder what kind of price tag I would be looking at £ to brace myself?
Anything could be done DIY to prepare it for marina and eventually save some costs?
And its only when everything else is good.
Pav.
Attachments
- MOA Position
- East Coast Captain
- Boat name
- WILD THYME
- Berth
- Suffolk Yacht Harbour
- Boat type
- Moody 425
- Cruising area
- North Sea, English Channel, Biscay
Hi Pavel,
Welcome to the MOA, and sorry to hear of your problem.
Your description of the remedial work sounds not too far out, if you establish that it's really necessary but just occupies a volume 8 to 10 times te volume of the steel it comes from so, despite your photos, you may not need to replace the compression post. I would be inclined to chip and wire brush the rust off the foot of the impression post to see how much steel remains. If there is sufficient, the remedy might be as simple as cleaning up and recoating with something like Hammerite.
Whether or not you replace the compression post, it's worth checking that the floor on which it stands and the mast plinth in the deck , which stands on the top of the post are both in satisfactory condition to support the mast compression loads. If the floor needs some remedial work, that will probably require the compression post taking out anyway.
If you are not comfortable making judgements about the amount of steel remaining or the condition ofvthe floor / mast plinth, I would get advice from a surveyor or a shipwright you can trust.
If your standing rigging is 15+ years old, it's due for replacement regardless of the compression post issues, so it sounds like your mast will be coming down anyway. While it's down, it is certainly worth a full overhaul of the main and genoa furlers and a thorough check of all other features of the rig (spreaders, mast head and foot sheaves, genoa halyard defector) and all the mast electrics. I know ti's is more potential expense, but it gets the most out of the cost of taking the mast down.
The other job you should do while the mast is down is to lift the little sealing plates around the chain plates, rake out the sealant resealwith a modern sealant and rebed the plates. The original sealant used for these tends to dry out and crack allowing water to soak into the marine ply bulkheads to which the chainplates are bolted. In extremis, this leads to rotting of the marine ply, so allowing the bolts to tear through the ply and the chainplate to come through the deck dumping the whole rig over the side. Keeping these sealing plates watertight is the key to preventing this. As a separate job, you should arrange access behind the beautiful cabinets in the saloon to check whether previous leaks have degraded the part bulkheads. You can read of Mike Hallgarth's dismasting here:
And the repair here:
The post replacement job can be done without taking the mast down by using a couple of Acrow props, one each side of the post, but it seems to me you will be taking your mast down anyway. Personally, I would replace the compression post with a new one in type 316 stainless steel once it has been removed, regardless of how much steel has been lost
You have already saved a few labour hours in getting access to the foot of the post and could really save more by taking down head lining to give access to the top. A key hassle is removing the table from the post which can put hours on the job, it's not clear what whether you have done that yet.
Lastly you are clear that you own Moody 376 yet in your name window it says you have a Moody 38 (2000s) this based on data you provided when signing up for membership. These are two completely different designs. You can update your membership details here:
www.moodyowners.org
The update will not happen immediately on clicking submit as it requires some input from our membership registrar, but it usually gets done within a few days.
Any further Qs just ask away.
Peter
Welcome to the MOA, and sorry to hear of your problem.
Your description of the remedial work sounds not too far out, if you establish that it's really necessary but just occupies a volume 8 to 10 times te volume of the steel it comes from so, despite your photos, you may not need to replace the compression post. I would be inclined to chip and wire brush the rust off the foot of the impression post to see how much steel remains. If there is sufficient, the remedy might be as simple as cleaning up and recoating with something like Hammerite.
Whether or not you replace the compression post, it's worth checking that the floor on which it stands and the mast plinth in the deck , which stands on the top of the post are both in satisfactory condition to support the mast compression loads. If the floor needs some remedial work, that will probably require the compression post taking out anyway.
If you are not comfortable making judgements about the amount of steel remaining or the condition ofvthe floor / mast plinth, I would get advice from a surveyor or a shipwright you can trust.
If your standing rigging is 15+ years old, it's due for replacement regardless of the compression post issues, so it sounds like your mast will be coming down anyway. While it's down, it is certainly worth a full overhaul of the main and genoa furlers and a thorough check of all other features of the rig (spreaders, mast head and foot sheaves, genoa halyard defector) and all the mast electrics. I know ti's is more potential expense, but it gets the most out of the cost of taking the mast down.
The other job you should do while the mast is down is to lift the little sealing plates around the chain plates, rake out the sealant resealwith a modern sealant and rebed the plates. The original sealant used for these tends to dry out and crack allowing water to soak into the marine ply bulkheads to which the chainplates are bolted. In extremis, this leads to rotting of the marine ply, so allowing the bolts to tear through the ply and the chainplate to come through the deck dumping the whole rig over the side. Keeping these sealing plates watertight is the key to preventing this. As a separate job, you should arrange access behind the beautiful cabinets in the saloon to check whether previous leaks have degraded the part bulkheads. You can read of Mike Hallgarth's dismasting here:
And the repair here:
The post replacement job can be done without taking the mast down by using a couple of Acrow props, one each side of the post, but it seems to me you will be taking your mast down anyway. Personally, I would replace the compression post with a new one in type 316 stainless steel once it has been removed, regardless of how much steel has been lost
You have already saved a few labour hours in getting access to the foot of the post and could really save more by taking down head lining to give access to the top. A key hassle is removing the table from the post which can put hours on the job, it's not clear what whether you have done that yet.
Lastly you are clear that you own Moody 376 yet in your name window it says you have a Moody 38 (2000s) this based on data you provided when signing up for membership. These are two completely different designs. You can update your membership details here:
Update Membership Details | Moody Owners Association
www.moodyowners.org
The update will not happen immediately on clicking submit as it requires some input from our membership registrar, but it usually gets done within a few days.
Any further Qs just ask away.
Peter
Pavel Hort
Member
- Boat name
- SOLITAIRE OF MYLOR
- Berth
- Mylor harbour
- Boat type
- Moody 376
- Cruising area
- Cornwall
Great and very helpful feedback Peter, thank you !
Details updated, so hopefully the right Moody will be selected this time!
First thing I will remove the fiberglass on top + around and rust to see what remained from the post plate, but I'm afraid not much left as I was able to slide out very big chunks of rust (not visible from my pics).
But at this point when I just found out today that both side stays are 25years old and front/back stays are even more than 25years: The mast will go down and will be inspected + re-new all the bits you have described + re-wired. New standing rigging seems to be must TO DO!
The compression post will be changed I guess the similar way as it is described in the article ‘The Mast Post’ by Mark Prior. Completely new or partially. I was told by boatyard to use galvanised mild steel for compression post due to its characteristics and not SS. = Still time to research. I will strip down the whole area including the saloon table (any tips or links to be found on MOA for the table removal?
As you named "The other job you should do.." is actually my nightmare after reading the chain plate threads and the dis-masting article last weekend. This is definitely on the list TO DO next ! I went through all the articles and Im not sure at the moment if I should remove the whole cabinets ( did not find any MOA article yet) or just cut out the inspection hatches. The hatches will be there either way as the varnished cabinets are not my priority. I don't exactly know the location of the chain plates on my 376 and their side of attachment so I guess to remove the cabinets would be more sensible solution and then make hatches on the correct places.
So far I have just exposed the babystay chainplate, but based on what I was able to see it is just something rusty behind fiberglass for me. Any thoughts?
Pav
Details updated, so hopefully the right Moody will be selected this time!
First thing I will remove the fiberglass on top + around and rust to see what remained from the post plate, but I'm afraid not much left as I was able to slide out very big chunks of rust (not visible from my pics).
But at this point when I just found out today that both side stays are 25years old and front/back stays are even more than 25years: The mast will go down and will be inspected + re-new all the bits you have described + re-wired. New standing rigging seems to be must TO DO!
The compression post will be changed I guess the similar way as it is described in the article ‘The Mast Post’ by Mark Prior. Completely new or partially. I was told by boatyard to use galvanised mild steel for compression post due to its characteristics and not SS. = Still time to research. I will strip down the whole area including the saloon table (any tips or links to be found on MOA for the table removal?
As you named "The other job you should do.." is actually my nightmare after reading the chain plate threads and the dis-masting article last weekend. This is definitely on the list TO DO next ! I went through all the articles and Im not sure at the moment if I should remove the whole cabinets ( did not find any MOA article yet) or just cut out the inspection hatches. The hatches will be there either way as the varnished cabinets are not my priority. I don't exactly know the location of the chain plates on my 376 and their side of attachment so I guess to remove the cabinets would be more sensible solution and then make hatches on the correct places.
So far I have just exposed the babystay chainplate, but based on what I was able to see it is just something rusty behind fiberglass for me. Any thoughts?
Pav
Attachments
Pavel Hort
Member
- Boat name
- SOLITAIRE OF MYLOR
- Berth
- Mylor harbour
- Boat type
- Moody 376
- Cruising area
- Cornwall
After removing all the rust flakes with hammer this is what has remained. About 3mm thick plate still attached to the post. It started to bend a bit as it is only 3mm thick now (i believe it was at least 5mm+ as new. What do you recon, still sailable far from the coast?
