Compression Post in the Bilge

[H33CRich]

I am in the process of purchasing a 1983 H33C and noticed a little problem with the compression post in the bilge. Until I get the surveyor in this weekend, I am going to wonder about it. It appears that there is a fair amount of corrosion from the hatch boards to the keel step. I have read an article on how to repair such an issue in Good Old Boat this past month, but is this something I should be concerned about on the H33C? Also, is there someplace where I can get the aluminum edging for the sole around the bilge? Click the link for the pic.

http://www.facebook.com/photo.php?f...57112907995.2146942.1257294391&type=1&theater

 

[DianaOfBurlington]

Aluminum compression post

Yeah; that's not good. There is no telling how thick that aluminum still is. I wouldn't trust it.

If I recall that comp. post is a stand-alone-- not against the main bulkhead since with the head aft there isn't a main bulkhead on that boat. That makes the post itself and the tie-ins at each end all the more important. Fix it before you go sailing.

You could hack it out with a Sawz-All and have a new one made. It is only aluminum, type 6066 or something close. See your metals guy and see what he has. Make it at least the gauge of the spar itself, or a gauge or two heavier. A section of spar would also work (often done over the years and looks better below). To determine the length add the saw blades' widths back into the piece you cut out. A wee bit too tall is always better than too short-- not because you can shim the shorter or cut off the longer but because you can wedge that sucker in there and get some of your sagged deck height back. An eighth- to a quarter-inch too long can be made to work.

It appears to be welded at the bottom to something. This makes it hard to repair-weld in place. If possible a strong sleeve could be welded like a cuff around the bottom,about 12" high, leaving the rest as-is. But you would have to be sure the welds were really good farther up because they'd be taking shear loads, not the best thing when it comes to in-situ welds like this.

Reinforcing it with anything else is really just a waste of time. Steel, galvanized, angle, etc. --just please don't go there.

This looks like bimetallic corrosion. Is it standing on some kind of metal bracket? If you must stand it right ON anything metal, don't. Make a pad out of G-10 or even any flat layup of fiberglass, bed it to the metal with 5200 and stand it on that.

If you have the opportunity to replace it, consider getting the whole thing anodised (after cutting and welding new top and bottom plates) or just Awlgripped (inside too, as far as you can reach). Putting a weep-hole near the bottom (and perhaps flooding it with epoxy till the weep-hole really is at the bottom) is a good idea. You could fit it with a plug to keep out critters.

It MUST have a flat plate welded to the top of it-- as well as to the bottom. You are not propping a picnic table with a 2x4 here. The flat plates distribute the load and on top it facilitates mounting deck hardware. Also with no main bulkhead you need the post to tie the hull and deck together in the first place (against upwards pull of halyard blocks on deck). So this member is structural in tensile as well.

Rest assured that this is what it looks like but it won't be any more. In this case it is what it looks like. Aluminum is not THAT expensive. Check surplus places. Any good plater can to anodizing-- ask about where you are. Welding is not a big deal either, nor expensive. If it were me I know a guy who would do it for steak and beer. Again, ask about. This is a relatively easy and cheap fix; so go for it.

 

[H33CRich]

Thanks JCII. The post will need to be replaced. I took a wire wirebursh to it during the survey and found pits between the the bilge boards and the step in the bilge, as well as the interface bebtween the step and the post. There is another piece of metal at the bottom of the post but not sure what kind. The post is 6001 accoring to a stamp found on it (blue ink of some sort) so I am guessing it is not original. The other giveaway is the oak plate at the head of the post. I agree that the replacement whould be straight forward. I will loosen the rig, fit a collar around the head, place a temporary post to collar (4/4), jack it up slightly to releave the pressure and see what we have... The strange thing is; the mast was just rewired and new standing rigging insalled. It should have been caught when this work was done. Then again, according to the yard, they only do what they are told to do.

I like most everything else about this boat. I have some cabinetry work to do, non-skid to freshen up (I like Kiwigrip and used it with great success on my current boat), cabin cushions to make, plumbing fixtures to replace and the water tank to consider what to do with (dry dired out scale and a few spots of white growth (bacteria of soe sort) from a year of being on the hard and 2-3 years of just lying in a slip), but the hull, deck, engine and instruments are solid; enough of a platform to work with and enjoy. She is going to be great!

 

[DianaOfBurlington]

I would prefer to hear that you'll do this work with the rig out of the boat. The 4x4 down below is likely to be in the way. This is one problem with the 33 having no bulkhead there. It's the cabin roof or nothing. You'll have to loosen it really a lot, almost leaving the mast flopping. This worries me. A gust of wind could set up enough movement to send it over.

You might try (very long) timbers holding it up at the base of the spreaders nd propped to the side rail. This would do something. Also a building or something nearby to prop it against would be a help.

The 6001 is probably original. Any 60-grade is probably adequate. 6061 is aircraft-grade aluminum, what spars should be. But if the walls are thick (like 1/4" or 5/16" it'll be fine.

A round section would be better than a square one-- lighter and stiffer. But go with what's there.

From your pic I cannot tell how it is supposed to be supported in the bilge. Is it over the step or just on it? Consider painting it-- even baked-on Krylon (use a hair dryer on low range for some time) would be better than bare metal. Anodising is fine so long as it doesn't get chipped. But it is worth considering that the existing post lasted 33 years and you're still sailing the boat. Make it a decent aluminum post and let the next guy a generation and a half away replace it then.

Good luck; and keep us posted with your progress.

BTW-- as far as the water tank goes consider the very excellent flexible ones from Plastimo, which got the best review in Practical Sailor when they reviewed them. I've got 2 on order for my boat.

 

[H33CRich]

I would prefer to hear that you'll do this work with the rig out of the boat. The 4x4 down below is likely to be in the way. This is one problem with the 33 having no bulkhead there. It's the cabin roof or nothing. You'll have to loosen it really a lot, almost leaving the mast flopping. This worries me. A gust of wind could set up enough movement to send it over.

You might try (very long) timbers holding it up at the base of the spreaders nd propped to the side rail. This would do something. Also a building or something nearby to prop it against would be a help.

The 6001 is probably original. Any 60-grade is probably adequate. 6061 is aircraft-grade aluminum, what spars should be. But if the walls are thick (like 1/4" or 5/16" it'll be fine.

A round section would be better than a square one-- lighter and stiffer. But go with what's there.

From your pic I cannot tell how it is supposed to be supported in the bilge. Is it over the step or just on it? Consider painting it-- even baked-on Krylon (use a hair dryer on low range for some time) would be better than bare metal. Anodising is fine so long as it doesn't get chipped. But it is worth considering that the existing post lasted 33 years and you're still sailing the boat. Make it a decent aluminum post and let the next guy a generation and a half away replace it then.

Good luck; and keep us posted with your progress.

BTW-- as far as the water tank goes consider the very excellent flexible ones from Plastimo, which got the best review in Practical Sailor when they reviewed them. I've got 2 on order for my boat.

Thanks John,
The boat is on the hard now and with power lines running down the property line that the stern is nudged up to. I will wait until next year's haul out to unstep the mast. The marine surveyor seems to think it was fine for now, just drill a weep hole at the base, dry it out (water may have come in from the step base and into the post, but we could not see any from the wiring port) and then fill the post base below the wire port with a thickened epoxy or some other filler. That will take care of it for this year.

For the other work that needs to be done, I still need to complete the closing on the purchase before I can really get into the guts of things. That should be within the next two weeks. The survey rated her in fair condition and as such am I trying to get the required insurance to even have the boat in a marina yard. My current insurance underwriter will only cover above average boats. :cry:

Plastimo seems like a good option, other than loosing 20 gallons of capacity with the triangular shaped bladder. The rectangular large capacity bladder hold 50 gallons, but not sure it will fit. Once again, I need to get into the project to sort it out. Thanks for keeping an eye on things. I will post updates as they become available.

 

[DianaOfBurlington]

You know, Rich, actually the idea of filling the corroded aluminum pole with epoxy is really a good idea. As long as you get enough epoxy in there-- using structural filler, not just cute powder. You'd have to drill a hole kind of high up and pour the stuff in, and be sure to fill it well up above the corroded parts. Then drill new weep holes at the new bottom of the empty chamber. Drill those first where you know it's still strong and when the epoxy dribbles out there you're done.

Best of all it would hold the weight and be durable enough-- until the rest of the post corrodes somewhere else.

But it's heavy and would take 50 bucks' worth of WEST epoxy (and why use anything else?). And it would be impossible to remove or replace with something 'righter' later.

And replacing the post properly is not really such a hard job at all.