De-masted!

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De-masted!

Postby CCaps » Sun Aug 21, 2011 6:18 pm

Hey team, was out on Greenwich bay here in RI for an afternoon sail, all was going well, had a good 3 person crew and felt really secure at the helm given that the winds were around 20 knots and there were some really rough seas (whitecaps). We were hiked out and having a blast the I heard this god awful sound and my mast came ripping down into the water. My starboard stay had broke off on the mast (the rivers appeared to have let go) and then the mast ripped out of the hinge plate. Luckily was able to save the mast and boom only losing a really nice boom vang I just purchased. We were towed back in and everyone was fine and in surprisingly good spirits about the ordeal. Now I'm left with a broken hinge plate and a mast that looks like a busted beer bottle on one end. Just wondering what people would consider doing for a fix? I'd have to lose at least 3 inches if I cut mast to be straight again, and I could buy a new hinge plate from dr marine. Is it advisable to cut the mast to a shorter length? Do you think the best option would be looking for a new/used mast? Use stronger rivets? Sorry for all the questions but this is such a helpful forum and I wanted to share my story as well with my fellow sailors.
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Postby Scott Mulford » Mon Aug 22, 2011 6:31 am

Sorry about the mishap.

I saw an O'day Javelin that had the same thing happen. Starboard chainplate broke however. The result was the same, mast fell over with damage at tabernacle. The bottom 3 inches would have to be cut to fix.

How damaged is the mast where the shroud attaches? If only the rivets came loose I would cut mast. If the mast itself is torn out where the rivets attach, I would look for another mast.

I think this problem is the only negative to cutting a keel stepped mast to make a tabernacle. If a stay goes the tabernacle won't hold.
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Postby K.C. Walker » Mon Aug 22, 2011 11:29 am

This is the lesson that gets you to inspect your rigging more carefully. In my case, been there done that. It was stainless steel that had micro cracks and corrosion that got me, a turnbuckle bolt and my stem head plate.

A shorter mast is not too much of a problem on a day sailor. That is, if this is the first time the mast has been shortened. You will end up with a 3 inch lower boom but it was designed with a high boom to begin with. In your case you might be moving the tangs 3 inches up for the shroud attachments, but that's no big deal. I think the original rivets are aluminum but as I replace hardware I go to stainless steel. I'm not really sure if it's necessary, though. If the boat has been in saltwater you really need to inspect for corrosion. The tang is stainless steel and the rivets were aluminum and the dissimilar metals will corrode. Also stainless steel gets much more corrosion in saltwater and especially in tight places.

Another alternative might be to sleeve the lower part of the mast adding back the 3 inches. You are in one of the most sailing intensive areas in the world so I am sure there is a rigger that could help you out.

My guess is if it had not been a tabernacle mast set up you would have had far greater damage.

Good luck! You definitely want to get back sailing because the best sailing of the year is upon us.
KC Walker, DS 1 #7002
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Postby jdoorly » Mon Aug 22, 2011 10:06 pm

Speaking of dismastings I was trying to careen the boat in the backyard to check the centerboard. But, when I pulled hard on the main halyard to get her over the port chainplate back-up actually pulled through the hull, stuck between the hull and deck, and separated a 4 foot section of the hull-deck joint.

There was no damage to my mast or home-made tabernacle other than the AWI sensor and cable which needed some solder, and the mast was still standing.

BTW I'm really pleased with my new tabernacle (mast hinge) having broken 2 of the Dwyer type in only 1 season. It's very sturdy even though it's positioned high enough to leave the boom and mainsail on when the mast is lowered for trailering. And, once I have the safety bolt in it stays up without stays!

957

I replaced the standard chainplate back-up, on both sides, with a 9" long 7/8" OD stainless thickwall tube. I drilled the 2 bolt chainplate pattern near the middle, then added another set of 10-32 bolts 1.5" in from each end to strengthen the hull-deck joint after I cleaned and re-epoxied the joint. (I had some difficulty clamping the joint and had to install temporary screws along the sheer., followed by filling the holes with a gelcoat fix kit)

I tend to go overboard with repairs but in this case I didn't add the fiberglass clothe to the sheer deeming it not necessary until the joint shows signs of reopening. Not to mention that's a lot more work and time consumed off-water.

My mast is 5.5" shorter than class rules allow, and in my quest to reduce lee helm I am adding more and more rake to the mast. For a few weeks now I needed to wear a helmet since the boom is so low! So, I added 4.5" of wood and a 3/4" wedge under the mast step to get the boom away from my ear. My original thinking was that this is a temporary fix to find out where the rig balances. Being 8" x 3.5" It seems sturdy enough in the for'n aft plane, However, I think the potential athwartships forces could break it and if I keep it I'll make it square instead of rectangular. I do have another mod in there that strengthens it though; a "U" bolt, which is bolted to the deck right in front of the mast with the threads pointed aft so I can clamp the mast at the partners (and it doesn't move!)

Good Luck CCaps
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Postby Alan » Mon Aug 22, 2011 10:50 pm

OK, I'm not being paranoid with the massive chainplates and 7/8-inch tubing backup plates. Good to know. :)

Jay, I've got a length of 7/8-inch stainless in my box of shiny stuff, and was intending to cut it in half lengthwise to make the backup plates. Sounds like you didn't cut the tubing, but installed it in its natural round state. Is that the case? Not a bad idea, if so - I found out that drilling stainless is far from easy, and I imagine cutting it might also be not so easy.
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Postby jdoorly » Mon Aug 22, 2011 11:51 pm

Alan, when I thought about what to use to replace the chainplate back-ups your earlier post about using 1/2 of a 7/8" tube came to mind. But when I found my 2 9 inchers and thought about slicing and dicing them, and remembering also my earlier experience with cutting stainless, plus I needed to strengthen the hull-deck joint- all of a sudden they looked perfect the way they were!

FYI In the past I cut SS tubing using a regular cut-off saw but with a metal cutting blade made of God knows what! I never tried to cut SS tubing lengthwise and I don't think I want to try, it's too hard to cross cut as it is! It seems more like your melting the stainless than cutting through it. I needed to dress the new edge with a belt sander, files, and a deburrer. Next time I HAVE TO cross cut a SS tube I'll first see if I can find a carbide hack saw.

I drilled it using a carbide tipped drill mounted in a drill press with a "V" shaped block to hold the tube, and the 3/16" drill still wandered around the center-punched spot.

BTW, these tubes come with one of two wall thicknesses: Thick is about 1/16" or .064" and thin is about .048" but this only becomes important if you want to fit a 7/8" tube into a 1"tube. then the 1" needs to thin.
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Postby Jeepman252 » Tue Aug 23, 2011 8:38 am

Jay,
Cutting and drilling SS really isn't that bad - I do it nearly every day at work (I work in maintenance in a food plant - lots of SS!). A good high speed steel drill bit will actually work better than carbide. The trick is to get ones with a "split point" instead of a conventional point. The split point is self-centering and is less likely to "walk" or wander when starting to drill.

As for sawing tubing , a "chop saw" with an abrasive wheel works best to cut crosswise. To cut lengthwise, either a vertical band saw with a good metal cutting blade or on short pieces, clamp it in a vise and cut it with an abrasive cut wheel in a die grinder.

I really like your halyard routing/tensioning setup - May have to incorporate that design on my II!
Larry
'83 DSII
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Postby Scott Mulford » Tue Aug 23, 2011 8:57 am

jdoorly..

Why the new hatch and tabernacle? Looks interesting and well done.
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Postby jdoorly » Tue Aug 23, 2011 10:56 pm

Thanks for the tips Larry.

Scott, I installed the hatch because I'm a decrepit old man and have trouble putting things in and retrieving things out of the cuddy. The hatch is made of standard hatch-stuff; 2 oak sides, 4 oak ribs, rounded front and back of oak, 2 layers of 3mm Okoume ply and 1 layer of 1/4" oak ply, varnished.

The 'door' to the hatch is still in 'prototype pine'. It is 3 hinged sections that fold down to make a seat or fold out to make a table, or fold up to close up the cuddy.

I wanted to be able to keep the boom in place and the mainsheet bent on while trailering to save set-up time. The Dwyer tabernacle proved too fragile and I think everyone that has one knows how easy it is to bend them. I decided that four 1/2-13 bolts going through 3/8" thick aluminum plates and the mast would provide plenty of strength. One of the bolts could be a pivot and one a safety. Then it struck me that this is the way boat builders have been making tabernacles since there have been tabernacles!

BTW, I have an "A" frame that acts like a gin pole to raise the mast. The forestay connects to the "A"frame and a 4 to 1 purchase from the "A" frame to an eye on the bow. The mechanical advantage is necessary, especially for me, because of the height of the mast pivot. When the "A" frame is not moving the mast it becomes a bow pulpit and makes me feel safe on the foredeck.
892
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Postby CCaps » Wed Aug 24, 2011 12:38 pm

Excellent info, jdoorly! Your mods are very interesting and well thought out. I couldn't agree more about the Dwyer hinge, that thing is was too easy to bend, I might go your route and fashion my own tabernacle. Sorry about your deck joint while careening. Hopefully we will get all these fixes in order for some more sailing!

Chris
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De-Masted

Postby Skippa » Wed Aug 24, 2011 11:34 pm

OK,
Can anyone suggest a source for 7/8 stainless tube?
Thanks
Kevin
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Postby ChrisB » Thu Aug 25, 2011 7:33 am

Kevin,

I glad to know its not just me. I've been following this post and thinking about making the same "upgrade" before the chainplate/deck joint fails. Defender Industries carries SST tubing, 2' x 7/8" OD x 1/16" thick (item # 755115)

-Chris
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Postby jdoorly » Thu Aug 25, 2011 2:53 pm

Larry, I should have told you...
The picture is missing the "battle axe" (the tensioner):
919
There was a small piece of 1" mahogany attached to the deck behind the cam cleats that had a brass bushing (pivot point) that the axe fit into and the mechanical advantage of the lever was thoroughly adequate to snug up the halyards.

However, I removed that system of halyard management. I found it was easier and faster to deal with the halyards using direct pull from the mast then through pulleys to the cockpit, also the cam cleats were 40 years old and often would not tighten on the ropes even though I wedged them, Not to mention, simpler is always better, and did I say the jib sheets fouled on the cheek blocks, a lot!
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Postby Alan » Mon Aug 29, 2011 12:45 pm

I got my 7/8 stainless tubing from www.bosunsupplies.com. It wasn't exactly cheap, so Defender may have a better price.
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Postby jdoorly » Mon Aug 29, 2011 8:11 pm

I haven't dealt with them yet but their price for 7/8" dia #304 SS thinwall tube by 2ft is $8. http://www.wholesalemarine.com Or, there are websites that will cut metal to size for you such as http://www.metalbytheinch.com but I don't think they have SS tube. There are others by I don't remember the name, try searching...
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