Bad compression post blocks

[c27dan]

Has anyone had problems with the lower shroud sagging when tacking. A buddy suggested that the wood block below one of the compression posts might be compromised. I guess it's time to explore with my oscillating saw.
Dan
Long Beach, Ca
wk #341

 

[sinnettc]

Before you start tearing the bulkhead apart check that your mast is centered and confirm your tensions with a Loos gauge.

To make sure the mast is centered I run a 50' tape up with the main halyard. I then measure to each outer chain plate. If it's not the same then I adjust accordingly until it is the same.

Next I try to get the mast straight. That's basically a case of adjusting the lowers until the groove appears to be straight. Running the halyard to the base of the mast and pulling it tight will give you something (fairly) straight to use as a guide. Once the mast is straight, use the loos gauge to adjust the tensions to match the manual or tuning guides. If you've done it right the mast is still centered and straight, and you're good for . . . . well . . . a few days or weeks.

Your rigging will stretch over time, plus the boat will change shape a bit as it adjusts to being in the water instead of on a trailer. It's not unusual for me to adjust the tension 3 or 4 times during the summer. I'll generally have to adjust a couple times the first month, then maybe another couple of times during the rest of the season. It's normal for the downwind lowers move around more as the wind speed goes up; That's because the mast bends due to the increased forces. Half an inch of movement is probably ok, but if it's extreme then it's time to tighten them up (or reef!). You'll find that you need to tighten the lowers on particularly windy days. FWIW, I always seem to have a bit more flex in one side than the other, even with the tensions the same. Quirk of my mast, I suspect.

Anyway, my point is, make sure the rig is squared away before you start tearing into the bulkhead. If it is, and you still end up with significant slack on one side, and not the other, then look at the compression posts, chain plates, etc. Don't skip checking below the chainplates too, as I seem to recall a case where there was rot at the base of the compression posts and not at the cabin top.

 

[jerrymlewis]

Adding to Chris' comments, I once had a MacGregor 25 that would PUSH the mast down into the cabintop (or else the boat was bending up like a banana or a smile) as it sat on the mooring ball all summer. I'd start the season with everything set nice and tight and then find all shrouds getting very loose as the season progressed.

When I first got my Capri (hull #155), I noticed the mast step had sunk into the cabintop, probably due to over-tightened rigging and heavy wind sailing on SF Bay. I added a 1/4" thick piece of aluminum the same width/length as the bottom of the mast step to bring it up to flush with the cabintop.

One hint: when sending my 50' tape measure up the main halyard, I tie the tail of the main halyard line to the halyard itself, creating a loop, so that I can pull it back down without depending on my attachment of the tape measure to the halyard (yes, learned the hard way).

Good luck.

 

[shnool]

I've never understood the tape measurement thing... except to measure out max forestay (which I just loosen now until I get my proper 10-12" of rake, but I digress).

If you loosen all the shrouds (uppers and lowers) then hand tighten just the uppers and lowers (low wind day, flat water, even heel boat). Take a halyard, and run it down to a chainplate... cleat the halyard off.. then swing it to the other chainplate... if under the same tension, they reach the same spot, the mast is straight up!

But back to the OP's question... it MIGHT be sagging, you might also be encountering some "stretch."
Like others said, rigging stretches to it's full length over time. after sitting for long periods they shrink back to normal (like line). Also heat/cold cycles will also slightly affect the length. Ideally you want to get to max stretch quickly though, so even a bit of early over-tightening, can get you to full stretch quicker.

Isn't there rod rigging below deck that counter-balances the shrouds on the Capri 22? could you have loose tension on the chainplate support with the rod rigging below (I always wondered about that with my CP22)?

http://www.ullmansailssandiego.com/ullm ... guides.php this says it better than me.. again I don't see the need for the tape measure but OK.

 

[dave_ren]

I've never understood the tape measurement thing... except to measure out max forestay (which I just loosen now until I get my proper 10-12" of rake, but I digress).

If you loosen all the shrouds (uppers and lowers) then hand tighten just the uppers and lowers (low wind day, flat water, even heel boat). Take a halyard, and run it down to a chainplate... cleat the halyard off.. then swing it to the other chainplate... if under the same tension, they reach the same spot, the mast is straight up!

Shnool, I was thinking the same thing. A cleated halyard is a tape measure without the tick marks.You just need to be sure that the points you are measuring to are symmetric around the mast step. One warning from others when I owned my Catalina 22 was not to count on the chainplates or lifeline stanchions to be in exactly the same spot on either side of the boat. Not sure if that is an issue with the Capri. It's worth measuring against two or three hard points on deck to verify the mast is vertical. As you said, holding enough tension to eliminate sag in the line will improve your halyard measuring stick too.

 

[c27dan]

Hey guys, thanks for quick reply... yeah rigging is tuned properly, mast on square and as "plumb" a boat can be in a slip. Chain plate connection and deck in good condition, bulk heads well connected. Where the stainless compression posts connect on their bottoms is where it might be flexing. Under it in a forward locker is a fiberglass wrapped 2x2. I'll check that out with a probing cut. One of the pro riggers here in the marina has gone over the rigging with me. Im religious with the Loos guage. I'll take some picks of project. Cat 27s and 30s, hell all older boats have the same potential problem with compression posts.Btw, a buddy with a '90 Capri 22 had his upper shroud pop out of his spreader, luckily a quick response saved his mast. He just bought the replacement shrouds, w/o pelican clip connecters from CD. Going to be over 100F today here in SoCal, it's not even cool on the water! Happy sails,
Dan

 

[shnool]

Dan good catch, Ok, was wondering where you had plywood for the chainplates... we were talking literally the bottom of the boat. Now it makes sense.

and that stinks (for repair)... Keep us posted.

 

[HERSH]

Would somebody clue me in -- what is this compression post you are talking about ?

Hershey

 

[sinnettc]

The compression post carries the load from the cabin down to the bottom of the hull.

Mark 1 models it's actually 2 compression posts, the metal ones on either side of the entry to the v-berth. I suspect there's something in the cabin top to spread the load across them.

On the newer Mk II there's a single compression post directly under the mast.

 

[HERSH]

Thanks -- little Brain Freeze here. Left over from the harsh winter I guess. Or old age catching up with me.

I want you guys to make sure your children, give you a lot of lot of grandchildren. I started collecting Social Security early May. Waiting patiently for my first check.

Hershey

 

[sinnettc]

I started collecting Social Security early May. Waiting patiently for my first check.

So you haven't actually started collecting it then.

 

[HERSH]

SS said around the 15 of June

Hersh