DS II Compression Post Area Cracked

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DS II Compression Post Area Cracked

Postby crocboy » Mon Aug 26, 2019 1:49 pm

I have a 1982 DS II and noticed a fiberglass crack in the cuddy right in front of the mast step. I took a picture from the cockpit access hole and found that the two screws holding the mast step (circled red in the picture) are not even directly over the compression post. I've heard this is a common issue on the DS II, where the compression post is not directly lined up with the mast step. How can I fix the fiberglass crack, and do I need to move the compression post as well?
Attachments
comp_post_2.jpg
comp_post_2.jpg (226.28 KiB) Viewed 1367 times
comp_post_1.png
comp_post_1.png (108.22 KiB) Viewed 1368 times
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Re: DS II Compression Post Area Cracked

Postby GreenLake » Mon Aug 26, 2019 6:22 pm

A crack like this could be due to mast step issues (likely) but also due to something too heavy placed on the cuddy floor (like e.g. a battery).

I would raise the mast, tension the rig and observe how much the crack widens. If there's substantial movement, you may not be able to repair without moving the support underneath.

In any case, any form of mere "cosmetic" repair risks failing. Your best bet would be to add a bit of strength, by building up a bit of a "plate" that overlaps the crack, but also extends underneath the mast step. To be clear, I'm talking about something that sits on top of the cuddy floor - yes, that makes the repair visible, but I fail to see any benefit that would make up for the complication of working this from underneath.

To avoid hard edges, you'll need to make a "pyramid" of layers, with each lower one wider than the one above by about 1". Top layer could be just the size of the mast step.

You can do the layup on a plastic sheet on your bench and then cover it with another sheet, so you can move it, and place in the cuddy in one piece. You can even let it cure a bit first (to the green stage, which is slightly tacky) and then use neat epoxy to glue it in place (works best if the two sides of the crack are level if unloaded).

Working this way is way more comfortable and probably results in a neater laminate. About 3-5 layers of cloth should do. If you want to use mat for some of the layers, it would have to be epoxy compatible (not all mats are).
~ green ~ lake ~ ~
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Re: DS II Compression Post Area Cracked

Postby crocboy » Mon Aug 26, 2019 8:41 pm

GreenLake,

What about a square piece of aluminum (about 12") that sits on the cuddy floor directly under the mast step?

Or possibly cutting an access panel in the cuddy floor and putting some kind of reinforcement post (4" PVC) directly under the mast step?

Also, why are they not aligned in the first place?
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Re: DS II Compression Post Area Cracked

Postby GreenLake » Tue Aug 27, 2019 1:52 am

The problem that I see is that you appear to have diagnosed the cause for this without sufficient data (or you didn't share that data in enough detail). The floor can crack for two reasons. One is that the mast rests on it and is not sufficiently well supported (in a way that the mast step can move so far down that the floor would have to bear loads it's not designed for. The other is that some other load (battery?) was sitting before the mast and the floor was not strong enough to support that (and couldn't give, because the support for the mast forces that spot up. (The third option would be that there's something about the way the boat moves in waves that would make the floor move, but it can't because of the mast step support - I'm excluding this scenario).

That's why I suggest that you rig you boat and see whether tensioning the mast causes the crack to open (before deciding on the best action).

The pictures aren't 100% conclusive. There appears to be a square plate below the floor and the screws seem to go into it, that should normally be enough and not a cause for worry. Since you seem to have an inspection port from which you can take pictures, I would also try to see whether the short mast support moves in any way when you add load (does it bend / lean?). If there's anything going on with the support yielding, then you most likely need to fix that.

If you decide that it's enough to add a "fronting" plate (i.e. a plate above the floor and glued to it), then it doesn't matter much whether you use aluminum or laminate something. Except that with laminate it's easier to do it in stair steps so you don't create a hard spot along which the floor would then have a tendency to crack again.

Are you by any chance unfamiliar working with fiberglass and epoxy? If so, it's not really that hard and even if you use aluminum, you'd need to glue that plate to the floor - it's not enough to just have it sit there; epoxy is the best glue for that. (We'll be able to talk you through that, if that's the problem).
~ green ~ lake ~ ~
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Re: DS II Compression Post Area Cracked

Postby crocboy » Wed Aug 28, 2019 8:20 pm

GreenLake,

After rigging it, it is definitely because of the mast. The crack is right between the top of the mast step and the area where the actual compression post is - because the mast step is directly over the compression post, there is a small area (1") where it is not supported. With the mast fully rigged, the crack widens and I'm not sure I'd want to take it out anymore. I'm debating whether to fix it above the cuddy floor with a large plate, or below by adding a second support post.

Still wondering why the original designers didn't line them up perfectly so it's supported. Do you know why that might be?
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Re: DS II Compression Post Area Cracked

Postby GreenLake » Wed Aug 28, 2019 10:44 pm

If mast and post are misaligned then I would do both.

A plate alone just spreads the unsupported load over a wider area of the cuddy floor; the plate would still be pressed down by the mast. Half the load would go on the post but the "free" end of the plate would have to be supported by by the floor (and it would carry a good part of the mast load, perhaps not actually 50%, depending on the length of the lever, if you get what I mean - if the offset is merely partial, e.g. some part of the mast sits over the support, a plate alone may be sufficient in distributing the residual).

You seem to have an inspection port that lets you view the mast support. If there's any way you can add something (or if you can cut a hole right where the crack is now to put something directly under the mast step. Perhaps a tube, or epoxy sealed bit of hardwood. Then you can cover the hole or crack with a plate glued to the floor, so it can help not only with spreading the load from the mast step but also help the floor stay up when you put gear on it.

The "why" of this particular defect isn't going to help you getting this fixed. Were all the workers stoned during those years? Or is it merely difficult to place a support "blind" between hull and cuddy floor and have it end up where the mast needs to be? I bet they thought their method worked, but they were lacking a suitable means of double checking (or thought the floor would be strong enough to equalize - well clearly, these floors have managed this task for many years before failing, so perhaps they were simply not counting on their boats to live as long?).

Whatever the reason, I think you know what it takes to fix this.
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Re: DS II Compression Post Area Cracked

Postby mtmckaig » Tue Apr 28, 2020 1:55 pm

I have exactly the same identical crack in the same location in my 1982 DS2. Not sure how to fix it. I am learning from the back and forth recommendations. Has anyone shared the repair aftermath? Second thoughts? If I was to do it again...? Did the crack come back?

I was going to reinforce the cuddy floor (10"L x 12"W) at the mast step location, with fiberglass mat layered below heavy 24 ounce woven-glass, then gel coat paint the repair after sanding and a hot coat of poly resin.

Should I move the mast step plate forward?

Any recent feedback is welcomed.

Thanks,

Mark
Attachments
IMG_9172 - Copy.JPG
1982 DS2 Mast step crack 3
IMG_9172 - Copy.JPG (75.41 KiB) Viewed 574 times
IMG_9171 - Copy.JPG
1982 DS2 Mast step crack 1
IMG_9171 - Copy.JPG (21.33 KiB) Viewed 574 times
IMG_9170.JPG
1982 DS2 Mast step crack 2 Location where plate mounts. Other holes are for CB rigging.
IMG_9170.JPG (19.65 KiB) Viewed 574 times
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Re: DS II Compression Post Area Cracked

Postby GreenLake » Tue Apr 28, 2020 4:23 pm

The crack is there (most likely) because the bottom of the mast is not supported correctly and puts a load on the cuddy floor that should not be there. There's a good chance the crack will come back if the support below the floor isn't fixed. There's no way an unsupported surface, even if reinforced, can take the full load of the rigging. It does need to be supported from below. It's possible that the damage comes from heavy gear stored in the cuddy flexing the floor where it is held fixed between lower support and mast. In that case reinforcing the floor might be sufficient.

If you are planning to use epoxy resin for the repair, be aware that you need epoxy-compatible mat (or simply use several layers of cloth).
~ green ~ lake ~ ~
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Re: DS II Compression Post Area Cracked

Postby mtmckaig » Tue Apr 28, 2020 7:23 pm

Thanks GL,

No heavy gear is stored. Obviously I am not the original owner so who is to say.

Seems from what I have read the compression post is slightly forward of the mast stub plate location and over time the downward force in addition to sailing up wind into weather, has over stressed the floor, and has torn the fiberglass.

To make the repair I need to open up the floor. I am including a picture of where I am planning to cut. Any advisement would be gladly received.

If I cut the cuddy floor to add another strategically placed support post, is there substructure I should avoid cutting through?

Somewhere I read that there are two support channels but I can not remember the location of the information to reread it; and more specifically what the measurements and reference points are. I have two bilge access fittings but my camera work is not so good.

Also, guidance for material to make another post would be greatly appreciated. 2 in PVC Pipe?

Thanks

Mark
Attachments
IMG_9176.JPG
Access compression post area by cuttting inside inner blue taped off area. Install new support post under mast plate.
IMG_9176.JPG (71.83 KiB) Viewed 561 times
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Re: DS II Compression Post Area Cracked

Postby GreenLake » Tue Apr 28, 2020 10:38 pm

You are correct, there is a support channel somehwere (I personally don't own a DSII, so my input is a bit second hand on this). Can you locate by knocking?

Where to cut? Suggest circular cut that can be covered with a deck plate. Always good to have an inspection port. I think aft of the mast plate, but check about that support - earlier posts here should tell you some of that, but you might be in for some patient reading.

Materials. Anything that promises to be as strong as the mast. PVC pipe, but diameter? The post required is so short, that you shouldn't get issues with buckling/bending, but the walls need to be strong enough to hold 400#. Sine you'll have cloth and resin, you could laminate one around a paper towel roll on your workbench, then cut to size. Something I would be tempted to do unless I had PVC pipe ready at hand. Definitely something to try if this is your first rodeo with glass & resin. Always good to practice on something that you can discard, and start over.
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Re: DS II Compression Post Area Cracked

Postby Leob1 » Mon May 04, 2020 9:57 am

I have the same crack on my boat. I performed surgery this weekend. As in your picture, the mast step was close to the compression post, but not over After cutting everything out, I was able to move the post about three inches so it would be under the step, no next to it. There where other things I found; the post(which is a couple pieces of PVC and a lump of filler) was fill with water. The plywood that was bonded to the underside of the cuddy floor was decayed, not rotten, but delaminated any on its way to being rotten. I'm in the process of putting it back together.
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Re: DS II Compression Post Area Cracked

Postby daysailingDFW » Mon May 11, 2020 10:05 pm

Leob - can you post some pics of what you found after cutting out the cuddy floor? Thanks!
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Re: DS II Compression Post Area Cracked

Postby Alan » Tue May 12, 2020 4:24 pm

viewtopic.php?f=2&t=5491

I haven't cut out the cuddy floor, but I've managed to take some pictures through the inspection ports. The link above has a couple.

I have a 1980 DSII and I don't know if the flotation tank in the first photo was used on other models, but it's probably far enough forward not to be a concern. The two stringers aft of the mast in the second photo would be best left intact. If I were doing it I would put a good-sized inspection port in the cuddy floor to one side of the mast (or maybe one on each side) so you can get in there and fix the compression post, then maybe later install a bilge pump.

(I said in the linked thread that the post was metal, but I think now that I was mistaken and it's actually plastic).

By the way, after staring at the boat for hours and hours, I finally developed a theory as to why the compression post is somewhat randomly located. I think the post was placed in its bed on the keelson in the hull molding, possibly with the resin that holds it in place not hardened, then the upper molding (cockpit and cuddy) was lowered onto it. The post would have compressed to the correct length as the upper molding was lowered, but if the post was misaligned as the upper molding was almost in position it wouldn't have been possible to see it or fix it.
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Re: DS II Compression Post Area Cracked

Postby GreenLake » Tue May 12, 2020 7:00 pm

You may be on to somehting
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Re: DS II Compression Post Area Cracked

Postby Champlaner » Sat May 16, 2020 4:48 pm

I cut a rectangle around the step in my cuddy floor for a different reason--the screws for the mast step (keel stepped) were stripped and it was loose. I was lucky enough to have the compression post well centered under the step. So I just added some epoxy coated plywood at the top of the post, 1.5" thick allow for future repair with longer screws. But a word of warning if you make these floor cuts: It might not be easy to keep the floor at it's original level. The floor is under stress and may have its own mind once freed in the center. I was worried mine sank too low so I propped it up before glassing my piece back in place. I ended up about 3/8" to 1/2" higher in the middle. As the old timers say, "You might wanna..." make some measurements or add some support before the floor is completely free from the post. I was not expecting this issue.

Pretty sure that filler in the post is gelcoat resin. Nothing stinks through a respirator when sanded like gelcoat. Luckily, my dinky original "turnbuckles" were able to take the extra height of the mast; I got more boom headroom; and she heads better than ever when I let go of the tiller. Phew!
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