Commander Compression Post Discussions

Does any one know exactly how the bottom of the compression
post is held in place? Do you have to remove the sole to inspect
it? It appears to be glassed in and sitting on the lead but its
hard to get an idea peeking through the bilge hatches.
I have cut out the core above the post to reveal rot and some
dampness. The top of the post is free and it can move around
somewhat. As I am soon to bed in a 1/4", tapering to 1", 8"
diameter , solid glass pad above the post I wonder what might be
done to the bottom while at this junture. Any Commander owners
that have had their compression posts out or any thoughts as to
what might lurk at the posts bottom would be greatly appreciated.
Cheers, B.
Commander#215

The top/cap of my compression post show signs of needing replacement. It is pie shaped and is slightly wider at the top. There is a metal washer about the same diameter as the bottom of the cap that appears to be through bolted to the mast mount on top of the deck. I am guessing that that washer spreads the compression load over the cap and supports the mast mount on the cabin top. The only through points are the small pipe lead the cabin top and the mast mount bolts.

There are several open cracks on the edge of the cap and the washer appears to have crushed into the bottom of the cap. I believe that the situation has gotten slightly worse over the past year.

Has anyone removed and rebuilt this cap? Has anyone made a mold to fabricate it? Is it possible to have this turned from wood and then glassed?

Suggestions anyone?

If I remember correctly, that pad is just a wedge of plywood. A replacement wouldn't need to be any fancier than that.

The sides of the pad are tabbed to the cabin ceiling. That fiberglass tabbing can crack or seperate from the pad. If that's all you're seeing, don't worry about it, its not important.

I would pull some loose tabbing away and see if the pad is rotten. Maybe its actually a deck core problem.

Got any pics? Is the mast off?

That title does sound like a bed and breakfast doesn't it. Join us for a fun filled day at the Commander Post & Pad...Water sports are available for the adventurous. Hmmmmm...

The mast is still up and I hope that I will get some more sailing in. My shrouds are barely taunt. I might be talked into tightenng them if it blows like it did last night. I was forced, mind you, into racing with a friend in one of these weeknight series. I was a gracious guest and didn't comment about how 12-15 was so delightful in my Commander...But there I was on a Catalina 36.....The cockpit was not 10 ft larger...but was a tad wider. They did roll their eyes a bit when I suggested that real boats had tillers.

I will take my digital camera out to the boat this weekend, and try to take some pictures. I was thinking I might also probe one of the cracks with an ice pick to see what is underneath.

Thank you for the information on the pad. If that is all it is, then I can, at the worst, cut the tabing, drop the pad and cut a new pad out of regular ply and glue it up with some epoxy. And then tab it back into place.

Here are the pictures of my compression post. First is from below and the second is almost direct on.

Here is the cap from the side looking forward.

That does have the general look of water damage.

What troubles me is that the tabbing has not only seperated from the pad, but has dropped down below the level of the pad.

It may be more than the pad getting rotten and squished. The deck core may also have gotten soft and the two skins are crushed together.

I would go ahead and cut away the tabbing, which serves no real purpose anyway. I would also drill some test borings into the underside of the deck. Just carefully pierce the lower skin and see if the drill produces balsa shavings or mush. The area between the pad and the forward hatch hinges would be most suspect.

Scrape the paint off the metal plate and see what's going on there.

Not much else you can do until the mast is unstepped.

I still wouldn't consider any of this to be a safety issue.

I have a bit of concern about the compression post on my boat. The steel is partially corroded where the post goes through the cabin sole. I don't know how to fix it, so I'm gonna ignore it.

CommanderPete,

I had some soft spots fixed around the forward port 14 years ago. Maybe it's time to do it again? My mast covers the mount but my recollection is that the bolts are what keeps everything from moving. It sounds like you have not removed the compression post either. I am thinking I might take my calipers and measure the amount of crush by the washer. If part of that is mast load, then it should recover some with the mast down.

Did they just take some wetted out cloth and lay it down over the pad?? I am trying to imagine the process of installing the post. I bet it was done before the floor was in. Your post is right on the seam.

Btw, what did you use on the floor? It looks great.

I can't figure out how they installed that post, unless they put it in before the deck went on top.

The pad just had some layers of glass wrapped around it and stuck to the ceiling/ bottom skin. Its certainly not needed to keep the pad in place.

The cabin sole is finished with Gymseal nonskid varnish. Good traction, wet or dry.

My post has a trim ring that sits at floor level, but essentially is the same as yours. I pulled at the tabbing and that washer appears to be at least 1/4 in. That is an unscientific estimate. And dusty crud came out. Trouble in River City.

Do I take a saw and cut out the pad. I looked at the floor this weekend to see if I could pull those two center planks, and that may be possible. One thought I had was to turn the pad very slightly oversize and then make a diagonal cut through the center. You could tap that in and fill it...I dunno. I keep hoping someone has done this and will speak up.

We had nice sails on Saturday and Sunday, but the winds were strange. Saturday I looked at the weather bouy on Stillwagen Bank and it was seeing 12-13 knots with gusts up to 16 kn. When we got out there about 2 PM, it was 5-7 knots but from the South. Sunday it was blowing a bit harder and from the E x SE and we got hit by a squall. Went back to Manchester under the main at 5 + kn. With lumps from Francis at 2-3 ft. Who needs roller coasters.

Is there anyone on the forum who has removed or repaired the compression post on the Commander?

I am faced with either tearing up the floor or removing a lage section of the cabintop in order to pull the pole out.

Still no solution in hand, but the boat is in the yard. Because I am a chicken, I am having my glass guy take a look. The step is loose, and I will post pictures tomorrow.

The post is still in place. I am more convinced than ever that the reason the pad is tabbed to to the cabin ceiling is because the post was inserted before the cabin top deck structure was put in place. The tabbing kept the pad in place until the step was bolted to the compression post. I think that if I need to replace the core over the entire area over the post, I will have it done from the top and then be able to place the pad from the top.

Here is my mast step....before

The scene of the crime!

A closer look. It does look like the core has been compromised.

The mast step seems to be in very good shape.

The cracks in the deck under it don't look so good. Gotta be a rotten deck.

On the inside, I really don't think your problem has anything to do with the compression post itself. You should be able to chisel out the old wedge-shaped pad at the top of the post and pound a new one into place.

Then re-core the deck leaving the bottom skin in place.

In any event, I took another look at my cabin sole. It looks like there was a seperate section of flooring installed around the post (between the two bilge hatches) about 4 "planks" wide.

This might explain how they installed the post with the deck on.

CommanderPete,

Yup, that is my conclusion as well. I am still chicken about doing exposed glass work. I glassed in the holes fom my old VDO skeg and Display head, and neither were pretty but they work. It's not that I don't know how to do it but I want to know what the cost is of having it pretty. He has done other work for me and does a very nice job.

When he went over the coach roof, he said it sounded good with the mallet, but that his meter picked up several wet spots. So I am waiting for his quote.

I aw the junction of the floor. I think that they tabbed the pad to the roof simply to keep it from moving around. That way they could pick up the entire roof - deck molding and just drop in place after the did the furniture and placed the post. Just a guess, but it makes sense.

Hi Pearson folks,
How's the sailing?
We have a question about our compression post, not actually the mast. At some point in time, a previous owner installed a cute little table in the cabin (uwhich we have currently removed ) and drilled some holes in the post to hold the table up. We were wondering if it is okay to fill those holes with some thick goopy schmagma-like epoxy and then paint the post white. Is there any reason that this wold not be okay? ..Also, does anyone know what the post is made of? We really want to make our interior nice, and thought this added paintjob would only enhace it.
Thanks for any supplied info!
Anthony/Bina
#155

Better yet, drive a dowel into the hole set in a little epoxy .

I believe the post is steel.

If the holes aren't too big you might be able to fill them with JB Weld (from the auto parts store).

The city of Dallas, Texas repaired a cracked Catapillar engine block with J-B Weld and saved $4,000.00 plus thirty days down time.

That's one incredible project mamager to get that many people to work together on one thing!

I guess the gennie is out of the tubes....

Working on the mast for Ariel #400....and looking for some advise
Removing the through bolts for both the spreaders and uppers - I found that there are no compression posts for these bolts to prevent the mast from being distorted or crushed. Is this the normal state of things?
I am also busy trying to remove the mast base to adapt a mast hinge - has anyone used a slide hammer to whale away at the base?

Don't think a post is needed. The load is pretty spread out and probably not too great.

While I had my mast down, I decided to retrofit compression pipes at the spreader brackets on the mast.

You can read-up on the concept, and can see the pictures of the install here (post #87+):
http://www.pearsonariel.org/discussi...ead.php?t=1552

Hello all,
I have experience removing and working the area of the compression posts on Commanders, don't know if there are any outstanding questions that I can help shed some light on. Here's a couple of points though:

1) The compression post is schedule 80 anodized aluminum.
2) The sole was installed first, then the post lowered down through the forward hatch and inserted into the cabin sole hole at a slight angle.
3) The lower end of the post sits on a built up fiberglass base in the bildge. Most likely with wood somewhere inside. The post itself is not glassed in.
4) The wooden wedge between the top of the post and the underside of the cabin is made of teak. The wedge is necessary for the same reasons the mast base has a slope to it.
5) Pearson cored the entire cabin roof, to include (unfortunately) the area immediatedly under the mast step.
6) The core is 3/8 inch end grain balsa.
7) Any detected movement is a sure sign that the balsa's integrity has been compromised. ie, water intrusion followed by rot / decay.
8) No work should be attempted with the spar (mast) up.
9) To remove the compression post strip away the very light tabbing around top of the post and with a block of wood drive the top of the post directly forward. Remember, the post was installed through the cabin sole hole at an angle and will come out at an angle. The biggest challenge will of course be in overcoming any downward movement the cabin roof made due the core failure.

I'll leave it at that for now, unless there are more questions of repair, etc..

Thanks,
Chance.

I appreciate your post.

Have you replaced the compression post with a laminated support beam yet? If so is the process detailed here someplace?

Your welcome.
No, I'm not replacing the standard compression post for a built up beam of some sort. On the commander, it is my belief that the compression post is the best way to go. If one were to say, want to remove it and do something like the Ariels set up, it would take major interior redesign and careful calculations to address the tremendous loads that the compression post carries, then where to fit everything in such a small cabin layout.
For an idea take a look at the Kittiwake's interior configuration, which is another Carl Alberg design. The cabin interior is small and there are what amounts to two load bearning posts on each side of the centerline cabin sole.

Thanks.

By chance, does anyone have a photo or two of the bottom end of the compression post? It would be helpful to see just what Pearson deemed sufficient in the bilge to hold up the mast.

Here is a picture of my post bottom. It does not look like the base it sits on was glassed very well.

I have seen a handful of post bases and they've all looked very similar to Jerry's picture above. It is not as pretty as the rest of the boat, but since this component works only under compression, it is built solidly enough. There is a teak block underneath the mess of glass as far as I've seen. I've cleaned-up C-155's a bit, but I decided to leave it alone as it is a hard area to work in unless you have the sole out - and I did not want to do that...
If you do some work in this area remember to provide drainage underneath or water will pool-up in the front... I've seen this too.

Thanks, captains!

I just wanted to see if it was more complex than I thought. Sure enough looks like what I found to be the typical 'outta sight' factory glass job on 113-get the fabric wet and stick in the general vicinity. I'd really hate to lose something and have to go fishing with a bare hand near there! I used to think cardboard cuts were bad until I got a good resin and fabric cut. (I just winced remembering.)

I was thinking about what design would still give the strength needed and let water pass underneath. I have the feeling I'm allready over-engineering this piece but it needs to be strong. Maybe something 'T' shaped that would allow water to pass on both sides, support the post over the upright body of the 'T' and be glassed to the hull on the top, flat portion of the 'T'. Or maybe just a block with a groove gouged in the bottom surface...

Sailor Jerry, is that a twist of duplex cable coming out of your post?

I thought the same thing when I first saw it. But believe it or not this is what it says on the cable (see picture below) which BTW has been removed. I plan to do away with the compression post and go to a strongback design which I will undoubtably over engineer like I do everything else.

Now I'm really curious... Why are you considering switching to a strongback? I suppose a strongback and accompanying bulkhead (if you're adding one) would make it easier to close off the 'head' compartment. That does seem to be a issue from time to time and depending upon who's on board. And honestly, at first I thought a compression post looked 'in the way' because I got so used to having an open passage throught the main bulkhead. But given the open plan of the Commander it started to make sense to me as far as hand hold going forward in the cabin. It sure does uncomplicate things when it comes to mast support. I guess ultimately this decision boils down to how you sail and use your boat.

It's funny. I'm thinking about taking out the strongback in favor of adding a compression post and you are thinking the inverse. Crazy world we live in.

Seriously though, I'm interested in why or how you have come to your decision.

"One man's trash is another man's treasure".

I guess the single biggest reason could be summed up in a single word which is family. Which is also the biggest reason I chose the commander to be my next boat. My wife sails with me most of the time when I sail. And a private head for her is very high on her list of necessary requirements.

Also I have two grown daughters. One of the main reasons for the commander was the large cockpit which allows me to take my oldest daughter and her husband and our two grandsons sailing with my wife and myself. And when you have that many folks on board you need a private head area even more.

There are however many other reasons for my choice and here are a few.

1.) I really dislike the post in the middle of the access to the v-birth. A lot.

2.) While per your post it may offer a handhold the edge of the doorway can do the same while allowing me to carry things into and out of the v-birth area much more easily.

3.) The partial bulkheads in the commander seriously limit what one can do for built in storage. A bulkhead that goes all the way to the deck will allow me much better options for the sink and stove and storage of galley items.

4.) We cruise a couple of times a year for a week at a time and we have another couple we sail with. The new bulkhead and curtain for a door will allow a little more privacy for us and our friends to get ready for bed and dressed in the morning.

5.) My previous boat had a strongback and it functioned flawlessly. I really liked that setup and I have no doubt I can engineer somthing for this boat that will do the same.

In the end I guess it boils down to personal preference. There really is no "right" way just a matter of choice.

Today is the day I drill the area beneath the mast step.. We shall see what I have to contend with. My plan is to measure the thickness of the roof along side the hatch with a large C-clamp and mark a 3/8th's drill to about 1/4" less that I measure. No junk or mess, no problem.

Valhalla has a track across the cabin for a 2 curtains that is installed at the bunk ends. My wife and daughter have been happy with that arrangement for a long time. Of course, It does help to have the curtains installed.

My rough measurement of the roof thickness on either side of the forward hatch of Valhalla comes to a smidgen less than 5/8" thickness. Does this sound right? I plan to drill a holes on either side of the step about 5/16" deep.

This is rough and gotten by measuring the height of the clamp screw of a c-clamp clamped on the roof and then measuring the clamp opening after removing the clamp and resetting the clamp screw to the measured height.

John,
I see you are addressing the issues you posted a few posts above...

You'll be happy when you are done...

Your measurements should be in the neighborhood... But the thickness can vary in different areas so you might see something different at the mast base area.
In any case - don't be shy. You already have a failure there... So removing the glass in that area will likely be necessary. just tear into it! Then reconstruct that area to the correct dimensions.

When drilling through a cored area; you'll feel the drill work its way through the top layer of glass and then it will go through the soft balsa like butter. The next hard surface will be the lower layer of glass.so it is easy to know where you are... But as I mentioned, I think that the area beneath your step has already failed, so you'll need to reconstruct. Don't bother reconstructing the core. The area beneath the mast step is small, and a solid base will work best under compression...

Just some thoughts - Good luck!

PS. Pls take a bunch of pictures as the work progresses!

John

As Rico has said the thickness can vary in the area of the mast step. What you have is 3/8" thick end grain balsa with glass on both sides. The bottom layer is usually very thin say 1/16" and the top varies a lot as I am learning. I just recored the area under the mast step as part of a project I will post in my gallery after I finish a bit more and can photograph it. But the top layer of glass under my mast was over 1/8" thick. It took me 7 layers of 1708 biax to fill the core area and another 5 layers to bring it up to the surrounding deck area. While I was at it I recored the area where the hinges for the forward hatch bolt through the deck. Here is a photo of the recored area.

So I lifted the mast step and drilled 3 holes in the deck area underneath the step. There appears to be a void after I go through the deck skin and then I pull up gritty wood fiber. So my assumption is that I have water incursion in this area and rotten balsa core. As soon as I tap outside the step area the deck sounds solid instead of the dull thump I get where I drilled.

So the area seems to be restricted. Will thinned resin or Git Rot work well. One of the fellows I have breakfast with used Git Rot on his Ensign and it has remained solid.

John

I believe Git rot is plain resin (either vinyl or Poly - do not recall...) with lots of solvents to thin so that the mixture better penetrates rotted material. As I mention above - it is simple & easier to just clean out all the balsa & make this small area a nice solid pad. This will give you the best material for the compressive stress.

Directly under the mast is a pretty critical area. You really want a sound foundation for the mast. And recoring that area is not a difficult task. If I was in the position you are in and not in the total refit position like I am this is what I would do.

Your mast step is probably 8" diameter, so draw a circle around the step so you know where the outside diameter of the step is and another 5" diameter circle in the center of the place where it sits. cut the top skin out in the area of the 5" circle. This will give you free access to the rotten balsa. The rot may extend beyond the 5" area but you should be able to fix that as long as it does not go too far. Then dig out the rotten balsa. Sand of any bumps from the top of the bottom deck skin but don't sand anymore than you have to in order to make it reasonably smooth.

Now if you had to dig out rotten balsa between the top and bottom skins of the deck around the perimeter of the 5" diameter cutout you need to fill that area with thickened epoxy. I would use some microfibers to give the epoxy more strength and cabosil (also called fumed silica or aerosol) to thicken it to a peanut butter consistancy. Then with a putty knife force this mixture in around the perimeter of your 5" cutout to fill the void between the skins of the deck. Let this set up before going to the next step.

The next step is to grind a bevel around the 5" diameter cutout. You want to grind the deck to about a 1/16" thickness next to the cutout and make a smooth bevel up to the point where the 8" diameter mast step is.

Now you are ready to start putting things back together. The first step is to cut 5" diameter circles of biax (I use 1708 biaxal cloth) to fill the area where the balsa used to be. If you use 1708 biax it will take approx 7 circles to fill this area to the same level that the balsa used to fill it. Next you need to cut circles that are progressively larger to bond back to the top skin of the deck. You need to make one circle 8" diameter, another one 7" diameter another one 6" diameter and depending on how thick your deck's top skin was possibly another one 5" diameter. These circles will bond to the beveled area of the top deck and tie it all back together. As you epoxy these larger circles in you want to put the LARGEST ONE down first which will give you a continuous bond of the entire beveled area and the recored area below it and follow with the next largest and so on.

When all this prep work is done you are ready to mix a small batch of epoxy and start putting things together. First wet out the area of your repair with straight epoxy and then start putting the 6" diameter circles in one by one and wetting them out as you go. If you run out of epoxy just mix another batch and keep going. When all of the 5" diameter pieces are in place and totally wet out put the larger circles down in the order mentioned above and wet them out completely.

After your repair is fully cured you will have a few high spots that will need to be ground down flush and some low spots that will need filling to make the area fair. So do the grinding and then mix up some more thickened epoxy with cabosil to a peanut butter consistancy and fill the low spots. You may need to do the filling operation more than once (after sanding the filler smooth) to get all of the low areas. When all of that has cured you will have a solid mast step you will never need to worry about again.

While this is how I would fix the problem your milage may vary :)
Sail on ~~~_/)~~~_/)~~~

Thank you everyone. Now as I take a deep breath, it looks like I have 3 choices:

1. Sell the boat (any takers??? HI)
2. Open up the deck underneath the mast step and pour in filled epoxy and put mat on top and cover with mast step.
3. As above but fill the void using built up modern coring and filled epoxy.

The consensus seems to be that a solid area underneath the mast step is best. I am busy this weekend so by Monday, I think I will open up the deck in about a 5 in. circle. I will have to cut back my mast light and antenna lines as well. The open area will give me a good idea of what I am dealing with.

More to follow, I'm sure

What do I do to raise the ceiling in the cabin? Or should I just leave it as is ?

Quote:

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Originally Posted by John

What do I do to raise the ceiling in the cabin? Or should I just leave it as is ?

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John the ceiling in the cabin should remain as is because you are not removing the fiberglass on the bottom of the deck only the top layer.

I apologize if I lost you on my explaination of the process. I often assume the reader knows more about the materials I'm talking about than is often the case. Sorry about that. Let me try and show you some pictures of what I'm suggesting as a possible course of action.

This is a picture of a couple of the areas on my deck where I am reinforcing for hardware and doing the same basic process as I suggested in my prior post. http://www.pearsonariel.org/discussi...1&d=1271034560

The one on the right is similar to what I had suggested you do under the mast. As you can see the bottom skin of the deck is still intact (except where some holes had been drilled previously) and the balsa core is removed from the center and the bevel and been ground into the top skin surrounding the hole in the center.

This picture shows what 1708 biaxial cloth looks like. Attachment 6738
as you can see it is heavy fiberglass cloth that is 8 oz mat stitched to 17 oz woven fabric. This is what I use to cut the circles out of to build up a solid glass and resin core in the center and what I laminate to the top of the deck as a new skin. By making the deck under the mast solid glass and epoxy you drastically improve the compression strength of that area.

Hope that helps, and while this may look like a large a scarry project (I remember when these kinds of things were scarry to me) it really is not bad if you take your time and fully understand what you are doing before you cut.

Jerry,

My concern is the incursion of the top of the compression post into the ceiling. I don't see any problem now, but if I leave things as they are, then it is an issue if I need to move the compression post at some later date.

Can you show a picture of what is going on?

Perhaps we are missing something in the communication... but...

You say that there is no failure now... Unless you are planning a drastic remodel why would you need to move the post in the future??? Besides - the addition of this solid pad would NOT prevent you from doing anything you can do now as this modification does not change the manner of attachment of the post/cabintop connection...

Perhaps you are not confident of the strength/durability of the suggested repair?

Consider that the original cored construction has done quite well all these years...

Solid epoxy is much stronger... And it is as excellent material for compressive resistance...

Let's consider:
The top of your post has a metal bearing plate which is some 6" in diameter. (The mast base is 8" - but let's consider the smallest area as an example as it is the weak element in this scenario)...
This plate bears on the inside of the cabintop below the Balsa core (which is already solid FG and will remain. You'll only remove the balsa core and will replace the FG layer at top.)

The compressive strength of epoxy varies a bit depending on the product, type of product, and manner of application, but it will range between 5,000 and 10,000 lbs/sq-in. Glass makes it stronger, but let's ignore that...

Let's say that you use bad epoxy and your install is full of holes and poorly applied... so we'll use 5,000 lbs/sq-in.

The bearing strength under these circumstances for the solid epoxy pad will be as follows:
The Area of the 6" plate at top of post 28.26 sq-in x 5,000 lbs/Sq-in = 141,300 lbs

So you see - the pad is actually the support system's new strongest point - far from being the weakest... the mast will crumble, the compression post will become a pancake, and everything -including the keel - would be pushed out the bottom of the boat WAAAY before the bearing pad you build even starts to consider failing....

Rico,

Attached to posts # 5 & 6 are earlier pictures of my compression post. The post cap has worked itself even further into the ceiling. Or if you prefer, the ceiling has dropped even further around the compression post cap. My point is that if I leave that where it is, I effectively will capture the post top by strengthening the area above it. I only asked if someone had been able to raise the ceiling enough that my post would be free to move and or remove. When I open the area above the cap, will the ceiling return to it's orginal form or do I have encourage (read force) the ceiling up to it's original contour.

I have a dremel like tool and for it I have 1 in + fiberglass reinforced cut off wheels. Can I use those to cut the deck to open up the void? Or am I better off going to Walmart and get their $29 angle grinder for that job?

Ahhh... I see.
I would suggest that you bring the cabin-top to its intended position for a proper repair job. The subsidence is due to the failure of the core and even though you would eliminate further deformation by making the repair where the pieces sit now, the best solution is to do it right. After all, once your commander is all shippy, you will not want to see that issue at the top of the post. It will not look right.

I imagine that if the cabintop does not pop back-up on its own, you can help prop it up into position fairly easily... Then do the repair as suggested. This is an important area, but it will not be hard to get it sorted out.

Your dermel-like tool may do the job, but it is a great big job for it... Not the best tool for this application. An Angle grinder with a cutting wheel, or even a skill saw with the proper blade would serve you best. Angle grinders are quite versatile. I'm sure you'll use it a lot if you cannot borrow one for the job, and end-up buying one...

BE careful with it though... They are powerful and can do lots of damage! (I am working on healing a nasty abrasion from one at the moment!)

Rico,

I am about to make the big leap, take a header off the tops, cut a hole in deck. I have a friend that is going to loan me his 6" angle grinder. Mask is at hand. Power to the boat. Can I cut a 5 in. diameter circle in the deck.? Can I mix up a gallon of epoxy to fill the void? Curious minds want to know.

It sounds like you are on your way!

See what Jerry has done on his commander for reference... Some lovely work there - you should follow his lead. And maybe you'll want to incorporate the mast base in your repair as he did... That is a great idea.
http://www.pearsonariel.org/discussi...1672#post21672

Cut a circle big enough to get to good-solid material... Since you already have a failure I would expect that the area will be the 8" circle (mast base), plus at least 2-3 inches around the perimeter which has suffered deformation. Make that whole area solid... Much less than a gallon!

I would not use pure epoxy. Use a bit of thickener and some glass mat on you repair. Jerry posted a good description of the process a few post above here...

I have a great mast step made of micarta by a PO. It is approximately 8" in diameter. I am hoping that I am able to cut a 5 in. circle and clean out underneath. If I have to go further, I will, but then will have to be neater in the replacement area. Because of the mast step, I will have to match the curve in deck so I get a good seating.

So the plan is to cut as carefully as I can, clean it out and then stuff it with filled resin......Sounds like I am doing a turkey, doesn't it. How much time to allow for the epoxy cure is a mystery but with some contemplation, I'm sure it will come to me. The other task is insure that the cabin ceiling returns to it's original contours. Easy beans ...ja'think.

John

I would like to offer a few suggestions that might make your job easier.

1.) For the small area you are working in a 6" grinder might be to large. I use a 4" grinder to grind in the bevel around the hole after I have cut it and even that seems a bit large at times.

2.) To cut the hole I often times use a small trim router similar to the one at this link. It allows me to control with a high degree of precision the depth of cut.

http://www.google.com/products/catal...CAcQ8wIwADgA#p

3.) If there is any balsa core intact under the cutout remove it carefully. It was bonded pretty well to the bottom skin which is often times very thin and fragile. Don't try to rush it just get it up slow and easy.

4.) Epoxy resin by itself is very brittle. You need the glass reinforcing to make this area strong. So cut all of your glass fabric pieces before you start putting things back together again.

5.) To keep a lot of resin from running down through the two holes that the mast step bolts through and dripping on your cabin floor you can wet out the top of the bottom deck skin and on a piece of visqueen (plastic) wet out the bottom piece of glass you will be putting in the hole. Then put the glass in the hole and make sure there are no air bubbles under it. Then let that start to kick and set up before you proceed with the rest of the glass. In addition I would use a couple of pieces of tape on the bottom of the holes to make sure nothing drips on the cabin sole.

6.) This repair will really take a small amount of epoxy. So mix small batches of epoxy so you don't waste it and it does not set up on you before you can use it all.

I hope this helps and I wish you the best on your project.

Jerry,

I am not fortunate to have a trim router but I have a regular router. Any reason not to use that and a 1/4" bit to cut the hole? I don't think the top skin is thicker that 3/8's and probably closer to 1/4." I have talked to my friend regarding borrowing his grinder, and he has some 4" blades for it. I think I am in good shape tool wise.

I don't think I understand what you are suggesting to do in the void area. My plan was to fill the entire area with filled epoxy and keep stuffing until I had the void filled and then build the deck area up to match the deck using glass mat. I I have a couple of choices for filler in the void including glass fiber, micre balloons (I don't think it's a good choice) or one of the other solid fillers.

John

A normal sized router should do the trick just fine. I like the little one but would certainly use one of my other routers if I did not have the little one. Also you will find that the top skin of the deck is closer to 1/8" thick than it is to 1/4" thick. The balsa core in the center of the deck is 3/8" thick and then you have the bottom skin of the deck that is close to 1/16" thick.

As far as the suggested repair I will draw a picture as soon as I can get some time later today and post it for you. But here are a couple of things I can tell you now. First, the tickened epoxy only goes between the top and bottom skins around the perimeter of the 5" hole you will cut through the top skin. And that assumes that the balsa core is degraded in a larger area than the 5" dia. cutout. While I'm on the subject, you need to know the only way to give the thickened epoxy body so that it will not sag out and run out of the area you are putting it into is to use cabosil (also known as fumed silica). You will want to use micro fibers or 1/4" glass strands to give the epoxy strength after it is cured but you will also need to mix in cabosil to thicken it to a peanut butter consistacy so it will stay where you put it.

Then in the area where you have the 5" cutout you will wet out possibly as many as 8 layers of 1708 biax cloth one at a time to build the core area up to the 3/8" thickness that that original balsa core took up. Then when you are built up to the the point where the glass is filling the core area and even with the bottom of the top skin you will lay down the 8" circle of glass first to get a complete bond with the entire beveled area and the glass you put in the core area. After that you will follow with the 7" circle of glass and then the 6" circle of glass and if the center is still slightly below the surrounding deck area one more layer of glass 5" in dia.

When all of this sets up use the grinder to knock down any high spots and mix up some more epoxy to use as a fairing compound and this time you will need to use cabosil and microballoons. Probably about twice as much microballons as cabosil. The cabosil once again gives the epoxy body and keeps it where you put it and the microballoons will make sanding it later much easier.

Does this help or would you still like the picture? I'm happy to do it but I have some work I need to get done before I can.

Jerry,

If I understand what you are saying, once I have cleaned out the bad core, I fill the void until I have a 5 in. hole from deck to ceiling. then I proceed to lay in glass matting until I get to the deck level. At that point I start using increasing sizes of mat to rebuild the deck as it was. I can then grind to match the deck, fill if needed and stand back and admire my work. Oh, yes, then I can remove the Gator tape (great stuff by the way) and re-drill the holes to mount my mast step.

I plan on placing a soda straw over my mast light wires and hopefully leave them so they can be removed or fished if needed. This does mean that the glass will have to be layed gently with a slit on one edge to accomodate the wires. Also, if the ceiling does not rebound around the compression post cap, my plan is to cut 2 semi circles of 1/4 plywood and gently jack up the ceiling until it matches the surrounding area an the compression post has a litlle wiggle to it.

John

I believe you are following but just to make sure I will post a picture later possibly as late as this evening.

John not sure if this picture will do more to explain or confuse but anyway here you go.

Attachment 6756

If this confuses I will try again.

John,
Jerry's above repair is very proper and the best and most permanent fix. Here is a quick and dirty repair that should get you at least another 40 years out of the mast step.
Use a 5" or 6" hole saw to remove the top skin, scrape out the bad core and dig it out from the edges until the balsa you are pulling out looks clean and dry. Using the same hole saw cut out a plug from 3/8" plywood. Draw a 8" circle around your hole and taper the edges out to that. Pack thickened epoxy into the void between the skins and lather up the bottom of the hole, stick in your plywood plug, butter everything up with the thickened epoxy and apply your repair plys of glass mat wetted out with epoxy. Pre cut your repair plys, mask off a large area and have every thing laid out and ready to go 'cause your going to be a sticky mess. If you put on 4 or 5 sets of rubber gloves you can keep peeling them off when they get too messy and you want to pick up a tool or something. The repair could be done with polyester resin instead of epoxy if cost is a factor, its not as good, but thats what the rest of the boat is made of.
.02 cents
Mike

Repairs have gotten more complicated. You can see pictures in the Mast Step discussion. I now have an open area of about 8" x 8" underneath the mast step. The compression post/wedge has already broken through the cabin ceiling. I am faced with raising the roof (really) and then rebuilding the entire structure. Also I did slip and there is a 1" puncture in the cabin ceiling. Fortunately, I am using a 1/4" bit in the router. Rather than continue duplicate discussions, I will continue the discussion in the Mast Step, as most seem to read both. Suggestions are welcome.