Rigging too tight - Mast compressed deck!

[mikebikeboy]

Originally Posted by Cruiser2B

I built a new beam and mast support system for my Alberg 30 out of G10 fiberglass board
My old blog may still be up Adventures of Salacia
Lots of photos....G10 is easy to work with...not too expensive and lasts forever.

Hey Cruiser 2B: I'm reading your blog and it's definitly giving me ideas. The G10 material looks like a dream to work with. You have any pictures of the finished product? And, how's it held up over time?

[sanibel sailor]

If no one has said it, post on the CDSOA (Cape Dory Sailboat Owners Assoc) forum. Vast wealth of knowledge specific to your model. I had a CD 26 and found it extremely helpful.

[mikebikeboy]

Originally Posted by sanibel sailor

If no one has said it, post on the CDSOA (Cape Dory Sailboat Owners Assoc) forum. Vast wealth of knowledge specific to your model. I had a CD 26 and found it extremely helpful.

Yes, I've got a thread going over there.

[mikebikeboy]

Got a quote back for cutting the piece of 4"x4"x0.5" 316 steel, $156

So total for the beefy piece of steel will be $340

I don't think that's too awful for what it is

I'm also considering making some arches on either side of the bulkhead out of G10, similar to what Cruiser2B did, as a general strengthening of the entire deck around the mast.

But that might not really be necessary after this beefy steel member is in place.

First step will be to cut away some of that ceiling liner to see what's behind there. Will post pics as soon as I can.

[Don C L]

I am still thinking the 4" hanging down will be extreme and if there were no downside to it, then fine, but I'd bet a 3" I-beam will hold over 10,000# over 22" span. There must be tables for that kind of thing in engineering books.
When I grow up I want to be an engineer.

[Carl-T705]

Join the members on the Cape Dory website to get pertinent information on your model CD and some repair ideas. The sailing season is winding down , so spend the time to tackle this repair. It's not a big job at all if you're the type of person who can work with simple tools . The mast will have to be removed, on a 27 footer it is a bit of a job for two people, but a crane can make quick work of it.

[Sailor_Grant]

The Cape Dory 27 has a unique deck step compression situation where there is a steel plate within the deck distributing the loads to the bulkheads.

Are you bulkheads rotten at all?

Are there any holes that have allowed water to seep into the deck and rot away the steel compression plate?

I have a Cape Dory 27 - PM me if you need any help, I have a lot of documentation on the boat and understand the rigging very well

[mikebikeboy]

Originally Posted by Sailor_Grant

The Cape Dory 27 has a unique deck step compression situation where there is a steel plate within the deck distributing the loads to the bulkheads.

Are you bulkheads rotten at all?

Are there any holes that have allowed water to seep into the deck and rot away the steel compression plate?

I have a Cape Dory 27 - PM me if you need any help, I have a lot of documentation on the boat and understand the rigging very well

Hi Sailor Grant - I've checked the bulkheads, I don't see any rot. There are signs of water intrusion underneath the mast boot. A PO had jammed a bit of paper towel between the mast boot and the liner, (maybe to stop a drip? ) which was kinda damp the last time I checked it. It's also stained a brown color which could be rust. Could also be tannins from the deck core, or plain old dirt. Not sure...

Will PM you!

[edlepera]

I was talking with a knowledgeable rigger about setting the tension on my Catalina 22, When we set it we didn’t used a tensioning device, being a deck step mast. We tuned it by feel.

[Moontide]

Have not read the other responses, but I would think that in most cases it would be virtually impossible to get the rigging too tight unless you did so unevenly and tweaked the mast. If you've ever tried to tighten a windward shroud while sailing you would find that it is pretty much impossible to turn the turnbuckle while under that load. If you try hard enough you might very well strip the threads before actually getting the shroud tighter.



The loads on the rig are pretty constant for a given force of wind (or wind and waves) and that is the compression load that gets transferred to the mast step. Tightly tuned rigs and loose rigs should have virtually the same loading in any comparable wind and sea condition for the same boat.


If I'm incorrect I'm sure I will find out now.

[mikebikeboy]

Originally Posted by Moontide

Have not read the other responses, but I would think that in most cases it would be virtually impossible to get the rigging too tight unless you did so unevenly and tweaked the mast. If you've ever tried to tighten a windward shroud while sailing you would find that it is pretty much impossible to turn the turnbuckle while under that load. If you try hard enough you might very well strip the threads before actually getting the shroud tighter.



The loads on the rig are pretty constant for a given force of wind (or wind and waves) and that is the compression load that gets transferred to the mast step. Tightly tuned rigs and loose rigs should have virtually the same loading in any comparable wind and sea condition for the same boat.

This supports my theory that this was an issue going back to before I owned the boat. I noticed a few quick fixes that someone had done which pointed to this sagging happening already.

Originally Posted by Moontide

If I'm incorrect I'm sure I will find out now.

[mikebikeboy]

Originally Posted by Sailor_Grant

The Cape Dory 27 has a unique deck step compression situation where there is a steel plate within the deck distributing the loads to the bulkheads.

Are you bulkheads rotten at all?

Are there any holes that have allowed water to seep into the deck and rot away the steel compression plate?

I have a Cape Dory 27 - PM me if you need any help, I have a lot of documentation on the boat and understand the rigging very well

Hey Sailor I've PMd you twice but no response. Perhaps I did it wrong. WOuld love to see the materials you have

Today I cut out some of the inner liner to have a better look underneath the deck. I saw rust. I think somehow, water is getting in there. Also, I stuffed a couple paper towels in there a week ago, and since then we've had rain. They were soaked, not damp, soaked.

Looks like I'll be recoring that area of the deck next spring.

[Don C L]

Originally Posted by mikebikeboy

Hey Sailor I've PMd you twice but no response. Perhaps I did it wrong. WOuld love to see the materials you have

Today I cut out some of the inner liner to have a better look underneath the deck. I saw rust. I think somehow, water is getting in there. Also, I stuffed a couple paper towels in there a week ago, and since then we've had rain. They were soaked, not damp, soaked.

Looks like I'll be recoring that area of the deck next spring.

Is there core in there? I would have thought not.

[mikebikeboy]

Originally Posted by Don C L

Is there core in there? I would have thought not.

I'm really not sure how this area of the deck is constructed. I'm hoping it's solid glass but from what I've learned, there are slabs of mild steel imbedded in there and if they get exposed to moisture they will rot, which I'm kinda thinking is what happened to mine.

[mikebikeboy]

I ended up going the compression post route. Seemed a lot more straightforward to me. I can easily slip past the post so it's just a small inconvenience. The post can be removed after the rig tension is eased a bit, so if at anchor for a few days the passageway can be cleared.