Mast step truss, inevitably:(

[MarkRyan1981]

Blimey Bob, that looks like a monster work of art and fits very neatly indeed into the truss cavity. That will last 'till the end of time!

Great news about your transverse beam. As with anything down in that dank dark world of the bilges, I suppose it is pretty critical to keep moisture well away from it. I bought some tef-gel to put on the threads of the M8 bolts, might be worth getting some of that for when you bolt through that transverse beam to keep moisture out? (as you rightly point out, "water gets everywhere" ). Once you have finished your install, do you mind if I snaffle your photos for my write up to give people both options when repairing their Ballads?

Hope all is settling down over there sir, keep us apprised of your progress with your lovely Ballad.

[Bob McGovern]

Welder did a nice job, staggering the welds to avoid distortion of the (relatively) thin steel. He cut it out of a 1'x2' plate. You could use 8" wide bar stock, but the distributor didn't have any in 316L. And plate is flatter, anyhow. By rough calcs, this truss is good for 60,000lbs compressive force to yield.

Had to grind down the nose of the foot a little, but that is expected. Otherwise it fits perfectly.

There was a pile of rust powder that came out of the clavicle area while cutting away the FRP encapsulating it, so definitely water has got in there somehow. But it was dust rather than flakes, and the steel shows pitting rather than onion-skin. I feel confident about the quantity of sound metal remaining. Will probably put plastic bushings (sleeves) around the thru bolts to prevent more problems, plus leave the bottom of the FRP envelope open for drainage. Will also sleeve the SS bolts holding the cast AL mast step to the SS truss. That should negate worries about galvanic rot. And hopefully we've fixed the leaks that were causing perpetual standing water in the bilges (chainplates, mast collar, ports, and cockpit hatch lids foremost contributors.)

[MarkRyan1981]

So you could sit a little under nine whole Albin Ballads on top of the truss? Awesome! Good idea sleeving all the fittings.

You hope to have it all back together to go sailing next season? Or are there more remedial adventures to be had before the boating ones begin? (I've just managed to sheer one of the bolts off my exhaust elbow when trying to service my 2GM20, d'oh, and so the challenges continue !)

[Bob McGovern]

Oh no. We're a long time from sailing anywhere. This summer was a complete write-down for boating matters. Sailed our little boat maybe twice in June; parked in backyard since. Sold our racing dinghy. Haven't spent more than three hours working on the Ballad.

Exhaust components are rarely salvaged. Most auto mechanics I know don't even try to unbolt exhaust flanges or couplings; they go straight to the die grinder/cutoff wheel. Life is too short to be finessing frozen bolts. You always want new ones on there anyhow, in case you need to change out the elbow while traveling. Should probably be a yearly maintenance item, pulling the elbow for inspection/descaling and swapping in new bolts.

[MarkRyan1981]

A bit like our sailing year, we haven't been for a sail at all - two chugs down the river Medway and back was the balance of it this year! When do you get the snow in your neck of the woods? I remember it was pretty stunning there last year.

The bolts on the exhaust elbow are threaded into the cylinder head unfortunately And they are not in a position where I can drill them out safely without removing the cylinder head entirely, so its a case of I get them free or its off with her head! Details below!

http://www.ybw.com/forums/showthread.ph ... heered-off!

[prjacobs]

Bummer! On automotive work I use an air-powered impact wrench on the rusty ones. Doesn't have to be a major sized gun, I usually start with a 3/8" drive small hand held gun, then use my wheel lug nut removing gun if that fails. More often than not they'll work loose and come out, but occasionally they'll snap anyway!
It seems rust responds better to impacts than to steady twisting. I would probably give the two remaining bolts a couple of sharp raps with a ball peen hammer to loosen the rust and let 'em know who's boss! Then try the impact wrench.
If you get them out you'll have better access to the broken ones. I use a right-angle adapter for drilling in tight places. That might allow you to drill the bolt and use an easy-out. Good luck!

[MarkRyan1981]

Thanks Peter, one notable gap in my arsenal is the lack of an impact wrench! With the use of copious heat from a mini blow torch, plenty of plusgas and some very gentle persuasion the other two bolts came off without sheering, phew.



I'm still having trouble removing the remaining stud though:



I've got a set of these on order: http://www.ebay.co.uk/itm/311191226556 that can be used with an impact wrench, I hope an pray they work with just a standard wrench! Else its head off really to safely drill that stud out .

[Bob McGovern]

Progress on the new truss! As much work as we're likely to finish this year, anyhow. First step is to put the old truss back in exactly where it was and transfer some horizontal lines, tick marks, and bolt-pattern marks onto a plywood template (which you will see in a moment):



Then set the new truss in place, check for horizontal using the template, and mark holes for the bulkhead bolts:



Drill those three holes (3/8" or 10mm). Bolt new truss into place, check horizontal again, align tickmarks, and mark mast base bolt-pattern onto new truss.



Then I drilled and tapped the new truss (5/16"--24tpi), which is not easy with 316L stainless.



New truss in place with template 'bolted' to it:



Mast plate will be within a millimeter or two of original location. I've also cut a new bilge divider/bulkhead/floor out of some phenolic countertop material, after first templating it in blue styroboard:





The flange on the truss will bolt to this divider (shimming as needed), and the inspection hole will help with airflow and monitoring of the space. I will drill weep holes for the truss cavity to drain into the main bilge.

[MarkRyan1981]

Gosh Bob, your are really surging ahead with your truss, that's not going anywhere. Did you drill the truss on a pillar drill by any chance? Impossible to drill accurately any other way I should imagine.

Interesting looking at your photos, is your truss (which is perfectly aligned with the old truss of course) slightly leaning to stbd or is that a trick of the lens? Will you bed the truss on thickened epoxy? Are you going to GRP the truss cavity at all (I had little choice after the hull split on extraction).


After this job is complete, how long is your job-list before she is all done?? (Mine seems to get longer rather than shorter... )

[Bob McGovern]

Mostly a trick of the lens -- notice the distance top of frame to cutout, and the black Magic Marker line extending to the right of the truss' bolted flange: that's your reference level. The camera is tilted a bit. But yes, the truss foot does need to be shoved right a bit (1cm) to achieve level. I took the truss out to temporarily install the bilge partition and didn't re-level it using the template. For final install, the foot will bed into thickened epoxy and two wedges along the sides will brace it level. Had a bit of time, warm weather, and a last bit of epoxy I wanted to use up before winter, so I glassed the front of the cavity this morning. Not as thorough as your fix -- just one layer of +/-45* biax, overlapped at the front for double thickness. When we glue in the partition next Spring, it will get some additional tabbing and cleanup, then the truss will go into place for good.

Drilled it by hand, in a vise. Not that hard if you centerpunch first & use cobalt bits. I wouldn't mind putting some locking nuts on the underside of the tapped holes, just as backup -- but that's going to be difficult to impossible with the divider in place. All the force is downward, anyhow.

Heh. Don't know what the underside of your 'cap' looked like (the FRP riser between truss and mast base plate), but ours was a joke. They just slopped in some bog when they glued down the cabin sole, and maybe two total square inches of contact was made between truss & cap. (Visible in background, photo 4.) We won't be re-using that.