Mast truss extraction from solid Polyester Resin

[RAI]

I did a similar job on resin (but with no hard filler in it) using an electric drill plus hammer and chisel. I ended with a fairly robust wood chisel and a clout hammer. I tried several drill sizes, even a 30 mm hole borer. The variation seemed to make the job less dull. I didn't find any other tools worked quite so well.

 

[MagicalArmchair]

Thanks RAI, I'll bring some (old) wood chisels down that I'll be able to get a bit more control of and get more of a point on than the cold chisels too. As you say, anything to break up the monotony of the job!

I'm going to get some SDS chisel bits today also - hopefully by the end of this weekend I'll have that truss out... (and Triola will still be afloat!)

 

[MagicalArmchair]

Re: Mast truss extraction from solid Polyester Resin - Now sinking! (a bit...)

Taking RAIs advice I shifted down a gear from a sledge and cold chisel to a small clout hammer and a skinny wood chisel. Progress was slow but steady and controlled. One of the reasons I shifted down was I noticed trace amounts of water in the front of the bilge that was salty - I mopped it up, and another teaspoonful appeared! Also just aft of the truss where I was chiselling, I noted the dust was sticking to my shoes: More salt water! :dejection:

The advanced form of the mast truss disease I am remedying is a split forming in the (1 inch thick!) front of the keel, and my interfering with the truss to extract it has clearly brought this foreward. So, its a haul out (again), inspect, and fill any crack before replacing the truss. At least out of the water I will be less worried about using power tools to finish the extraction. :encouragement:

The below illustrates just why this job needed doing (if there was any doubt) - note the hole at the back should all be solid plate. This was brisk sail away from failing I would suggest:

About 50% of the resin has been removed:

Avast! There be salt water there, there be!!

 

[RAI]

I had a similar problem to your keel crack. My problem was caused by the stress at the mast root/support caused by the fore and back stay hauling up the bow and stern. Obvious really. Out of the water the crack closes when the boat's weight is on the keel
My solution was 12 layers of carbon fibre/epoxy layup both inside and outside the hull to spread the load. So far it's working (still, after 9 years).

 

[MagicalArmchair]

Well, its out! The SDS drill was a god send and actually was far less brutal than a hammer. For work closer to the hull I used a small wood chisel and a hammer.

Naaa, that had another two or three seasons in it... :hororr: ...maybe

 

[Concerto]

Well done Mark. Now onward with the repairs and relaunching.

 

[MagicalArmchair]

Thanks Roger, hope your trip to Burnham went off without a hitch and you got that deck done.

I’ve opened up the front of the keel where the extraction process along with the expansion of the rusted truss split it. It’s actually more like 20mm thick there, so, once I've tidied the hole up, I will fill 13mm with 402 ("choppies") and Colloidal Silica thickened epoxy and then bevel out 7mm to around 15:1 (about 100mm out each side, made up of 14 layers of glass in two stages). Then four layers of fibreglass on the inside to complete the hull repair. The surrounding GRP looks solid, so that’s a good start.

For the truss, I'm favouring what the surveyor suggested (and 30boat) of a wood composite option. This consists of two bulkheads fore and aft in 1 inch Robbins super elite plus marine ply, sealed with three layers of epoxy, before being bedded and ‘glued’ in with a putty of 404 (high density) thickened epoxy putty. A plywood beam running fore and aft connecting the two bulkheads (this too sealed in three layers of epoxy). These will all be fully encapsulated in four layers of fibreglass to strengthen it further and bond it fully to the hull.

An oak cap will then be added to the top of this structure to spread the load of the mast foot with grain running perpendicular to her centreline, this will mate with the GRP mast foot shim (which makes up part of the GRP saloon sole). The oak platform will then be tapped to M10 and injected with epoxy when the bolts are put in place.

Job done, go sailing... (in 2020 )

 

[pmagowan]

Well, its out! The SDS drill was a god send and actually was far less brutal than a hammer. For work closer to the hull I used a small wood chisel and a hammer.

Naaa, that had another two or three seasons in it... :hororr: ...maybe

Is that the new part? Looks good and strong, how are you going to attach it

Well done with the removal, I bet you are glad that is over!

 

[MagicalArmchair]

That's right, comes with a 30 second warranty and a guarantee to bring the mast down around your ears. Yours for a fiver!

I've done some grim jobs in my time on boats, but none have had me doing a full Basil Fawlty on my boat (after a few solid thumps on my hand with a hammer)

All I needed was the twig and the tux and it would have been a dead ringer.

 

[MagicalArmchair]

So thats the front of the keel repaired then!

Drilled out the crack with a slight bevel for the first 13mm, and created a 15:1 bevel on the remaining 7mm around the crack:

Filled the 13mm with 'choppies' (503 filler) and colloidal silica.

Created and cut out the 14 layers of fibreglass to build back up the 7mm.

Finally, apply all layers to the hull finished with peel ply to leave the finished surface amine blush free and ready for fairing and finishing. Phew

Next will be fairing, patching the coppercoat, and then rebuilding the truss - sailing again by 2020

 

[Concerto]

So thats the front of the keel repaired then!

Next will be fairing, patching the coppercoat, and then rebuilding the truss - sailing again by 2020

As soon as that Mark! I saw you working on Sunday, but decided to leave you to get on with the repair. It seems I was wise considering your timescale!

 

[30boat]

So thats the front of the keel repaired then!

Drilled out the crack with a slight bevel for the first 13mm, and created a 15:1 bevel on the remaining 7mm around the crack:

Filled the 13mm with 'choppies' (503 filler) and colloidal silica.

Created and cut out the 14 layers of fibreglass to build back up the 7mm.

Finally, apply all layers to the hull finished with peel ply to leave the finished surface amine blush free and ready for fairing and finishing. Phew

Next will be fairing, patching the coppercoat, and then rebuilding the truss - sailing again by 2020

Congratulations,that's beautiful work!

 

[MagicalArmchair]

I'm surprised you recognised me Roger in all my PPE - a friend of mine commented I looked like something out of Breaking Bad...

Thanks 30Boat, I had lots of input from here, Wessex Resins (the West System reps) as well as East Coast Fibreglass - they'll all be sick of my many questions by now I'm sure.

 

[MagicalArmchair]

So the inside of the hull is now repaired and the truss is in!

Four layers of glass over the whole foot location and up the sides of the hull (after all that smashing on block of resin to extract the truss, I thought it prudent to strengthen the whole area). A further four layers of glass over where the crack in the hull had been.

Glassed in, with peel ply on top:

Cut and dry fitted the bulkheads, truss, and cap.

Three layers of epoxy over all the cut ply, followed by peel ply. Cap built up with 404 filler to create correct angle for the sole and mast foot to sit on.

Glued in with lots of fillets using 404 high strength filler with one layer of glass over the top as a final barrier to water.

Plastic tubes glassed in to add drainage if water does somehow manage to get into the truss area. A channel from the forward locker to the aft locker using extruded fibreglass tube, bypassing the truss area completely.

I just need to glue back down the sole and bond in the six M8 machine screws that will hold the mast foot and once its set, the rig can go back up.

 

[30boat]

So the inside of the hull is now repaired and the truss is in!

Four layers of glass over the whole foot location and up the sides of the hull (after all that smashing on block of resin to extract the truss, I thought it prudent to strengthen the whole area). A further four layers of glass over where the crack in the hull had been.

Glassed in, with peel ply on top:

Cut and dry fitted the bulkheads, truss, and cap.

Three layers of epoxy over all the cut ply, followed by peel ply. Cap built up with 404 filler to create correct angle for the sole and mast foot to sit on.

Glued in with lots of fillets using 404 high strength filler with one layer of glass over the top as a final barrier to water.

Plastic tubes glassed in to add drainage if water does somehow manage to get into the truss area. A channel from the forward locker to the aft locker using extruded fibreglass tube, bypassing the truss area completely.

I just need to glue back down the sole and bond in the six M8 machine screws that will hold the mast foot and once its set, the rig can go back up.

You ,Sir, are an artist!!

 

[MagicalArmchair]

Thanks 30boat. My surveyor, Alf Cackett, is down this weekend to give it the once over before I seal it all up. At the risk of overengineering the whole thing, I am contemplating scratching up the bits without peel ply on and sticking another couple of layers of glass over the whole lot (the is only one layer of 300gm glass over the structure in addition to the three layers of epoxy). Likely overkill, but for the extra peace of mind...

 

[30boat]

Thanks 30boat. My surveyor, Alf Cackett, is down this weekend to give it the once over before I seal it all up. At the risk of overengineering the whole thing, I am contemplating scratching up the bits without peel ply on and sticking another couple of layers of glass over the whole lot (the is only one layer of 300gm glass over the structure in addition to the three layers of epoxy). Likely overkill, but for the extra peace of mind...

Go ahead,no harm in that little extra strength.

 

[MagicalArmchair]

The truss is now covered in two extra layers of fibreglass and epoxy - well, all apart from where it didn't quite make it around the bevel on the aft end of the truss and 'bubbled' up - so that has been ground carefully back to 1 layer of glass. That will all be covered with solid, 404 thickened epoxy anyway, so I am not too concerned.

One curious thing is that the new truss is completely level, as was the old metal truss, however, if I put the sole back on level, it no longer lines up (by a fraction) with the rest of the sole. I can only presume that the sole was fitted slightly p***ed when the boat was manufactured. And yup, the boat is laying perfectly level out of the water.

I'll refit the sole perfectly level, and level out the sole when I glass that section back in I think.

 

[MagicalArmchair]

Full write up of the problem for Ballads here: http://www.albinballad.co.uk/about-the-albin-ballad/the-mast-truss

Shebeen had a very similar experience to Michael_W on his Ballad - he sent me some smashing photos (cracking would be the more fitting superlative) of his fix and a subsequent problem with the beam forward of the truss. http://www.albinballad.co.uk/about-...ast-truss/shebeens-truss-and-transverse-beam/

Just need to find some time to write the fix up...

 

[MagicalArmchair]

And finally, a (mostly finished) write up of the fix for those who have not drifted off to sleep: http://www.albinballad.co.uk/how-tos/fix-your-mast-truss/