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Help...detached mast step!

Started by JustStartin, November 07, 2009, 09:51:10 PM

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JustStartin

While prepping my boat for winter storage my wife and I were bringing the mast down on our 1983 ComPac 19.  As we brought the mast down slowly, the mast step pulled away from the top deck and eventually came right out.  I'm thinking that I can use screws/sinkers and 3M 5200 to remount the mast step to the deck.  Can anyone provide some insight as to what I might be up against and if I should do something different?

newt

it seems like the repair would be in two parts:
1. Repair the cabin top and fiberglass/gelcoat the deck
2. Thru-bolt with matching plate inside. There- that ought to do it for another 20 or so years!
Oh- and make everything watertight with 5200.

JustStartin

Quote from: newt on November 08, 2009, 09:43:05 AM
it seems like the repair would be in two parts:
1. Repair the cabin top and fiberglass/gelcoat the deck
2. Thru-bolt with matching plate inside. There- that ought to do it for another 20 or so years!
Oh- and make everything watertight with 5200.

I like your idea.  My only question is how to mount the matching plate on the inside.  The mast step is directly above the wooden "stanchion" that is in the cabin.

Craig Weis

#3
It's up to you if a new outside piece of tin [stainless steel] is plopped down on top of the cabin top and then the tabernacle holes drilled clean through using the tabernacle as a template. And then bolted and all gubbered up with 3-M 5200 slow set. The 5200 takes three days to cure.

It's all about spreading out the forces. Here is the other danger. Forward and aft stays, and to a lesser extent the side stays being so tight that the mast is being pushed through the bottom of the boat.

This statement from a earlier post is a bit incorrect...
"I like your idea.  My only question is how to mount the matching plate on the inside. [?]  The mast step is directly above the wooden "stanchion" that is in the cabin." Actually the holes will be around the circumference of the compression post. One or two will actually be drilled clean through the overhead lamp if you don't take the lamp down first. The bolts will be so close to the compression post [with or without a new inside plate] that getting the washers and nuts on the new bolts will require a bit of prying to cant them out far enough from the compression post to start the nuts. But it can be done.

The answer about the new inside plate is to...

1~Remove the inspection plate on the vee birth deck in front of the compression post [note that the compression post NEVER sits-rests-or contacts any part of the keel. The compression post just is screwed to this former.

2~Unscrew the two wood lag screws under the inspection plate going through the post and into the plywood former that creates the wall/step between the two quarter births and the vee birth.

3~Take the pole out, the tabernacle screws actually goes around the post. Not through it. Putting the post back may require coping out the compression post wood for the new through the cabin screws. Think about it.

4~Unscrew and remove the overhead light. Or I just drilled through the overhead lamp fixture and nutted. Can't see it with the lens cover on the lamp if not using an inside plate.

5~Hold the inside plate up to the overhead and have a helper from outside on cabin top mark the previously drilled-through-the-cabin-top old tabernacle holes. If you have not done this yet drill the holes clean through now.

6~Take the new inside plate down, drill the marks.

7~Get the tabernacle cleaned-up and and ready for 3-M 5200.

8~Goop up the new plate and slap it up to the over head.

9~Goop up under the tabernacle and fill in the void of the cabin top. Don't worry about the extra goop squeezing out all over, it'll drip all over and get all over your hands. You'll have two days to wipe it up before it's too dry to wipe up.

9~Have the helper fish or screw in the four new machine screws that your going to use to hold the tabernacle.

10~Mind the assembly. From the top--> the screw-the finishing washer-the flat washer--->the tabernacle--> from the inside--> the new drilled doubler plate-another flat washer-a locking washer-and the nyloc nut. Acorn style or not.

11~If your really good the screw won't be too long to fit a decorative acorn nut. Or you can nut, remove the nut one at a time, shorten the bolt to fit, and then re-nut using an acorn nut after the job is all done.

12~At this point put the compression post back in. Might have to sand it's top to fit under the new plate. I'd just hammer it in and put the lag screws back in and call it done.

Been there done it years ago. All is still well. . I actually see no reason for an inside or outside doubler plate. But you can make a sandwitch if you want to.

newt. Yea your right. I had forgotten that the 23 has no compression post. Other then that the jobs no different. Actually easier. So sorry. skip.




newt

Ummm...gulp- yeah what they say. I havta eat crow on this one, because my CP-23 does not have a compression post. I assumed (you know make an a$$ out of ...) That your CP-19 was just a smaller version of what I have. I will not make that mistake again. Once again- do what they say!!!
Newt(feeling not as confident a sailor as he thought he was!)

Bob23

   I'll drink to Newt's idea of a interior matching ss plate. But as Koinonia's mast step has never come off, and I hope it never will, I don't speak from experience, only speculation from an engineering mind.
   The 23's mast load is transferred to the keel via the bulkhead, I believe.
   I'd sail with Newt or any of you fellow Compac-tors anytime. I've only had occasion to sail with a few, so far, and it's been a blast.
   Not to change the subject, but a fellow site-man has just purchased a CP27, invited me to go on the delivery voyage...stay tuned for a story!
bob23
 

brackish

My first concern would by why it came out.  I would dig around in the screw hole(s) and see if there is any wet rot there.  If so that needs to be addressed. 

If not, and the screws came out with dry wood on them, then what force caused it?  Don't know about the 19, but on the 23 the step channel width is too wide for the mast extrusion.  The tendency might be to tighten the pivot bolt too much and "clamp" the channel to the mast even when the nut is backed off.  Then instead of pivoting on the bolt with all the force transferred to the back edge of the mast on the step until it rises in the slot enough to pass over center, it pulls the front edge of the step up.

After replacing my step, I installed nylon spacers to keep the step channel open.



I was advised to let what happened to you happen if it has to.  A $23 dollar step much better to replace than a $1500 dollar mast.  If the aluminum (I'm assuming 6061 or better alloy) in the mast pivot bolt area yields, that aluminum won't easily reform, tends to fracture.

I also installed a block on the back section of the mast base to help with the forces on that edge.  Don't know if it helped but it felt right.  I used a chunk of corian that I had left over from a kitchen counter job, but I think delrin or similar would be better.  Screws and epoxy.





Time will tell if improvements did any good.  If I had it to do all over again, I would install a Dwyer mast step that has an open L slot where the pivot pin does not ever come out of the mast.  I would also install a reinforcing tube in the inside of the mast for the pin.  There is a Dwyer step that actually fits the Compac extrusion perfectly.  But I would still install the step so that it would be the first item to fail and pull out.

B.Hart

   This summer on my 16 I replaced the wood block under the mast step by cutting out the inside of the cabin roof and removing the soggy cardboard and rotten block.  The problem with not repairing it is there will be a void up there, one thing is to force epoxy into the void to fill it, then remount the step.    BILL 

Craig Weis

#8
'There is a Dwyer step that actually fits the Compac extrusion perfectly.  But I would still install the step so that it would be the first item to fail and pull out."

WELL; THAT'S BECAUSE THE MAST IS A Dwyer Mast and boom are right out of the Dwyer catalog.
Like you, I placed fender washers between the mast and the inside of the mast tabernacle. And between the bolt head and butterfly nut on the outside of the tabernacle. Spread out the forces over the surface of the fender washer.

I don't think that the bottom edge of the mast can be 'oil canned' from standing the mast up on it's edge when going up or down.
But what I see on C&J is that the finishing washers on the tabernacle screws [bolts] have worked four flat spots on the bottom edge of the mast. This effects nothing. Just an observation.








Ship quality marine aluminum alloy in 5052 5083 5383 *5086 5454 5456 6061 and extruded through a die becomes very hard. Even though aluminum is not much more then compressed mud.

Very hard to believe that the hull bottom plates * are  not any heavier then 4mm, 6mm and 8mm thick. That's nothing yet she'll beat through the wave at about 50 knots. I guess that's why PJ Yachts calls these designs Sport Yachts.

See that molded ship's glass on the boat? That's $800,000 worth of melted sand from PPG. And only one fellow from Cuba, living in Miami, is certified by Lloyd's of London to install the individual pieces. He's a very nice guy, brings a crew of three with him when PJ Yachts calls him up, once the glass is delivered.

You might notice the Texas State flag on the mast to the right of the Stars and Stripes and left of the Wisconsin State flag on the dock at Great Lakes Yacht Service. The gal who owns the business'es late husband started a little company called Texas Instruments, and her uncle invented the Lava Lamp...how groovy is that?
skip.

brackish

I don't think that the bottom edge of the mast can be 'oil canned' from standing the mast up on it's edge when going up or down.

My trailing edge was already curled and chipping when I bought the boat, so straigtened it enough to install the block.  Now it pivots on the block.  Plan to spray a little teflon spray on it when going up or down, should ride nicely.

I worked in an aluminum extrusion plant in the late sixties as a puller, stretcher operator and saw operator.  Too early to have made any Com-Pac masts, but surely made others although not sure who for, just saw a run number with the customer usually a wholesale fabricator rather than a boat manufacturer.  Water cooled, port hole die, very slow runnout.

Depending on the alloy, aluminum can be very soft (EC, 6063) or tough as nails (508X series, 2024 T4, etc.).

nice boat in the picture.

Frank