Mast step truss, inevitably:(

[Bob McGovern]

Last piece of boat work before winter. I glassed in the keel area with that lovely, conformable 1708 biaxial fabric and epoxy, overlapping the two sides at the front by 10cm or so to create double thickness where the seam is.



Next year we will tab in the partition, bed in the truss for good, and rebuild the sole around the mast area. Since we plan to lay down fake wood flooring, we're not to concerned about making it all pretty.

[MarkRyan1981]

Nice work Bob, did you use peel ply on top to remove the amine blush and create a key for your secondary bonding? Or do you use a non blushing epoxy? Below is my offering. I thickened the base with 404 high density filler to get into all those little air bubbles in the first port of polyester and to create a fillet.



I have been contemplating fake wood flooring too! This is the stuff I've been looking at: http://www.robbins.co.uk/marine/cabin_cockpit.asp I haven't told the first mate (Liz) yet as I've very nearly bankrupted us so far this year with all the boat spend

[Bob McGovern]

No peel ply, tho I have experimented w/ it in the past. The bond was to older polyester & glass, well ground back and wiped with xylene to remove any factory wax. All the biax was laid in a single go. And this discount epoxy I use is a 3:1 mix & less given to amine blush than 5:1 WEST -- which is notorious for blush. I'll still rinse it before painting with BilgeCoat or the remaining Sikaguard 62. Will want to see how the water drains.

One useful feature of peel ply is reduced resin-to-glass ratios if (if!) you really squeegee it out ... and if you really care enuf to try. I find biax 'floats' less than woven fabric and gives up its spare resin pretty readily, w/out developing dry areas like wovens can. I really like biax. Anyone chasing absolute minimum resin ratios whould be using prepregs or vacuum bagging, anyhow. I'm content to work with chip brushes, two plastic squeegees, and if feeling really posh a ribbed aluminum roller.

[MarkRyan1981]

Yeah I didn't really squeegie it very hard, I did have a half hearted attempt , however I go pretty crazy with the consolidation roller.

Humm, I didn't put any further coats on and left mine as epoxy, I figured epoxy is pretty 'water proof' (we all know no epoxy IS actually water 'proof', but for our purposes it is waterproof enough). I will paint the bulkhead in the bilges mind you, just to make it look pretty like the rest of the bilges .

And yes, West blushes like crazy, although it does comes off very easily with soapy warm water (I did try cold non soapy water to start with - and that just smears it around!)

[Bob McGovern]

No need for paint; the epoxy is waterproof enuf for this location. But painting (white or light grey) will make it easier to inspect later for rust staining, standing water, etc. Those show up better against a uniform backdrop.

[MarkRyan1981]

Check out Aprils Practical Boat Owner. They only published my keel crack article! When I get a moment, I'll scan it in

http://www.albinballad.co.uk/how-tos/fi ... your-keel/

Its basically the above.

[Jan_Ballad_323]

Wow, what a great thread.
I been reading it all now, more intense than a very good book.
I bought ballad Nr. 323 (built 1973) last season, and was until recently unaware of the problematic mast truss construction of the ballad.
My heart sank a bit when I learned about it, as I have planned for laucnhing the boat in water in a couple of weeks.

I have bought an USB endoscope today and I will inspect my mast truss this weekend. I keep my fingers crossed that It looks as
Mads did a couple of pages back, then I believe I can safely await until next winter to remove the truss and build a new one.
If it looks like the ones of Bob and Mark, I think I will "take the bull by the horn" and postpone the launching of the boat a couple of weeks and follow through with a removal of the old truss and inserting a new wooden one. This thread is really invaluable, thanks guys for so carefully documenting and sharing your processes!!

Update:

This is how the mass truss looked like. Looks pretty ok I believe. I don't think there's any acute need to replace it.

my_photo-7.jpg (38.34 KiB) Viewed 105651 times

[Sanlen]

I've done some investigation on Sanlens truss the last couple of days. Purchased a endoscope USB camera and drilled some holes but found it hard understanding what I was looking at

So I drilled some larger holes where I could get two fingers down and touch the truss. It feels completely solid and no rust dust appeared on my fingers. It was easier to use the camera through the larger holes but I still didn't quite understand what I was looking at

I feel a little relieved. Maybe Albin Marin changed the design somewhere down the road. Hull number is 547.

The bolts and what can be seen of the truss are without signs of rust and the truss itself seems to be galvanized (or even SS, I have to check with a magnet). I wonder where the rust-coloured water came from earlier (before I sprayed some rustprotection from the bilge in under the truss)

IMG_2602.jpg (32.6 KiB) Viewed 105648 times

[Bob McGovern]

Jan (#323): Your truss looks very clean, like Mads'. I have no idea why some appear impervious to rust and others are mere lacework-iron, but you seem to be in the good luck camp. I'd check your keel for any sign of splitting, then go sailing. Welcome to the forum, BTW.

Jan (Sanlen): Happy news for you as well. If the truss is rotting, the rust tends to be highly apparent near the surface (see Mark's initial inspection photos). There will normally be flakes everywhere. Your bilge rust might be from the 'clavicle', the wishbone steel beam just in front of the truss. Your last two photos suggest a bit of rust-swell and leaching near its bottom edge. See just left of the limber hole in photo 3. Our clavicle had some surface rust, a few flakes near the bottom, and lots of rust powder; but it also has plenty of sound metal left up higher, which you can test by scaling it with a screwdriver or drilling thru it. So I plan to leave it alone. Tabbing the bulkheads in place (top-hatting) and possibly to the overhead would help strengthen the hull in that area, too: I think the clavicle was necessary because the bulkheads (just bolted to one-side tabbing) did not supply enough stiffness there.

[MarkRyan1981]

Indeed, I only wish mine had come up as clean as yours then I wouldn't have missed a season sailing . The peace of mind is worth those holes, as the wise Bob suggests, time to go sailing.

As for the transverse beam, I've left mine in, however Shebeen replaced hers. I documented it here:

http://www.albinballad.co.uk/about-the- ... erse-beam/