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Repairing wooden shoulders
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andymck...@gmail.com
Jun 8, 2015, 7:59:47 AM6/8/15
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Our club has an old (late 1980s?) Janousek coxed 4 that has suffered several cracked shoulders. The first time it happened we had it professionally repaired - but we now have two more cracked shoulders and two more that have signs of rot. The cost of professional repair would easily exceed the cost of buying a boat of equivalent vintage/quality. But the cheapskate in me hates the idea of scrapping a boat (and I'm not sure how I can fit it in a green recycling bin), so I was taking one last look at DIY repair.
The problem is that the ribs are in a sealed compartment! The under seat area has an access hatch towards the rear of the slide that gives access to the shoulders at the forestay position (which aren't the ones that failed!). The underseat compartment appears to have a transverse bulkhead halfway along the slide - so even if my arms were long enough to reach, you can't access the shoulder at the main rigger attachment. The portion of shoulder above the slidebed is encased in fibreglass.
It looks like a repair would involve cutting away the fibreglass around the upper part and de-laminating the shoulder from the saxboard, is it that simple? But without access under the slidebed I don't see how to remove broken material, or install a new rib. Has anyone experience of doing this? If I needed access to the shoulder in the sealed compartment where would I cut - a new access hatch or can one open the bulkhead at the end of the enclosed space under the slidebed?
Andy McKenzie
The problem is that the ribs are in a sealed compartment! The under seat area has an access hatch towards the rear of the slide that gives access to the shoulders at the forestay position (which aren't the ones that failed!). The underseat compartment appears to have a transverse bulkhead halfway along the slide - so even if my arms were long enough to reach, you can't access the shoulder at the main rigger attachment. The portion of shoulder above the slidebed is encased in fibreglass.
It looks like a repair would involve cutting away the fibreglass around the upper part and de-laminating the shoulder from the saxboard, is it that simple? But without access under the slidebed I don't see how to remove broken material, or install a new rib. Has anyone experience of doing this? If I needed access to the shoulder in the sealed compartment where would I cut - a new access hatch or can one open the bulkhead at the end of the enclosed space under the slidebed?
Andy McKenzie
stan...@gmail.com
Jun 8, 2015, 8:16:59 AM6/8/15
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basically it involves chiselling/ cutting a 2" wide hole the width of deck- replacing the shoulder and making it snug to the saxboard- epoxy and thin glassplys and a lot of clamps. Then replacing the missing bit of deck- the janousek kit came with a pice of honey comb and a template for fitting- then sanding and making good.
I'll admit the first one I cut out scared me but it works quite well I'd allow 2 to 3 weekends roughly:
Day 1 cut out and strop old bits of shoulder and either fit new shoulder or make new shoulder to fit.
If I was more professional as a boatman and didn't have a life outside of rowing this could probably merged days one and 2.
Day 2: epoxy shoulder in with multiple plys to bond it to saxboard and bag/ tape and clamp allow to set.
Day 3: Debag and clamp- clean up shoulder saxboard join. cut honeycomb to shape- fit and glue + plys over the top + tap + weights- it's nt a practical location to clamp.
Day 4: Fill sand, refill re sand etc all bits until looks good enough to paint
Day 4a/5 depending on degree of perfectionism (required) paint.
Day 20- spot severa small l bits you wish you could redo but boat is now in use by summer novices and that never happens ;-)
hope this help,s
stan
andymck...@gmail.com
Jun 8, 2015, 9:07:55 AM6/8/15
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Thank you! Very helpful answer, and sounds like it's not an impossible task, - sounds like I'll have to give it a go (or even better persuade another club member to give it a go!).
Andy
rolyb...@googlemail.com
Jun 8, 2015, 11:48:58 AM6/8/15
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Andy,
If you heat where you want to make a hole you can cut the composite with a sharp knife.
Roly
If you heat where you want to make a hole you can cut the composite with a sharp knife.
Roly
robin_d...@hotmail.com
Jun 12, 2015, 4:44:00 PM6/12/15
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Have done this on a 1985 Janousek that we obtained for free and would do more boat repairs on the rest of the fleet if I didn't now have a 3.5-year old.
As far as I've been able to pick up for the last 15 years, Janouseks pre 1987 or thereabouts had all wooden ribs. Pre 1990 or 1991 the boats had half-wooden ribs (the main shoulder at front stops was replaced with a big composite moulding for the next 3 years; the back-stops remained wooden until this time or thereabouts). After that they're all composite and no longer a problem. Our Janousek fleet date from 1983 (3x), 1985, 1987 and 1996. Over the past 8 years we've suffered many shoulders going rotten just underneath the deck (you see a crack in the paint appearing around where the rib goes below deck level owing to flexing while being rowed) owing to water accumulating on the wood when the boat is on the shelf which then causes local rot. We cannot leave hatches open in the boathouse owing to nesting birds (wrens and robins, mostly!) so basically the boats are doomed to go wrong.
Last repair I did (a 1985 boat), I used a Dremel to cut across the deck around 60mm parallel lines outwith the rib to the gunwales. Then I chiselled down between the shell moulding and the rib until it snapped off at the break point under the decking laminate level. I cleaned the remnants of adhesive off the inside of the shell. In the base of the shell, two triangular pieces of plywood with screws joined the two half-ribs together. I unscrewed the screws and took out the lower piece of plywood, and unhooked the lower end of the broken half. The broken lower half and the upper half of the same rib were put back together and used as a rough stencil to give a shape onto a piece of paper to get the shape. I then cut this back with a scalpel and used it as a template to cut a new half horse-shoe-shaped piece of plywood (around 18 inches long overall and roughly boomerang-shaped). Once confirmed that this was about right and with the ends cut/sanded to fit the gunwales and base of the shell, I then layered the faces with 2 layers of 200gsm linear carbon impregnated with West resin (2 pieces on each face over the angle corresponding to roughly 12 inches each by 50mm width). Once this had set, I then cut it back and sanded to the edges of wood, then faced it on the front with thin woven carbon & resin. Luckily it fitted fairly well. The cut-out deck piece was bonded back in using SIKA thickened 2-part epoxy resin (the grey gritty stuff that they sell in the B&Q construction area for bonding bolts into concrete but is also pretty good for deck / rib repairs), sanded back and finally glass-fibred over with a 3-layer patch made of 60gsm glassfibre, 3 layers of filler primer and then top coat paint.
As far as I've been able to pick up for the last 15 years, Janouseks pre 1987 or thereabouts had all wooden ribs. Pre 1990 or 1991 the boats had half-wooden ribs (the main shoulder at front stops was replaced with a big composite moulding for the next 3 years; the back-stops remained wooden until this time or thereabouts). After that they're all composite and no longer a problem. Our Janousek fleet date from 1983 (3x), 1985, 1987 and 1996. Over the past 8 years we've suffered many shoulders going rotten just underneath the deck (you see a crack in the paint appearing around where the rib goes below deck level owing to flexing while being rowed) owing to water accumulating on the wood when the boat is on the shelf which then causes local rot. We cannot leave hatches open in the boathouse owing to nesting birds (wrens and robins, mostly!) so basically the boats are doomed to go wrong.
Last repair I did (a 1985 boat), I used a Dremel to cut across the deck around 60mm parallel lines outwith the rib to the gunwales. Then I chiselled down between the shell moulding and the rib until it snapped off at the break point under the decking laminate level. I cleaned the remnants of adhesive off the inside of the shell. In the base of the shell, two triangular pieces of plywood with screws joined the two half-ribs together. I unscrewed the screws and took out the lower piece of plywood, and unhooked the lower end of the broken half. The broken lower half and the upper half of the same rib were put back together and used as a rough stencil to give a shape onto a piece of paper to get the shape. I then cut this back with a scalpel and used it as a template to cut a new half horse-shoe-shaped piece of plywood (around 18 inches long overall and roughly boomerang-shaped). Once confirmed that this was about right and with the ends cut/sanded to fit the gunwales and base of the shell, I then layered the faces with 2 layers of 200gsm linear carbon impregnated with West resin (2 pieces on each face over the angle corresponding to roughly 12 inches each by 50mm width). Once this had set, I then cut it back and sanded to the edges of wood, then faced it on the front with thin woven carbon & resin. Luckily it fitted fairly well. The cut-out deck piece was bonded back in using SIKA thickened 2-part epoxy resin (the grey gritty stuff that they sell in the B&Q construction area for bonding bolts into concrete but is also pretty good for deck / rib repairs), sanded back and finally glass-fibred over with a 3-layer patch made of 60gsm glassfibre, 3 layers of filler primer and then top coat paint.
wmar...@gmail.com
Jun 13, 2015, 7:25:48 AM6/13/15
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A thin chisel can be made from an industrial hacksaw blade and a little grinding. Snap the blade, grind off the teeth, and grind a blade onto one end. Grind as a chisel, not as a knife, and you'll have a good tool for prying boat parts apart without snapping things.
The last Janousek/Carbo-Craft knee/rib that I replaced was actually during the 80s, but I did an entire four... The knees had all broken.. Finally got the boat back on the water, and on its first outing it was driven into a 250 m pylon, destroying the bow. Guys (prepping for national trials, IIRC) had gone out unaccompanied while their coach was helping someone else...
Ellen Braithwaite
Jun 22, 2015, 11:51:54 PM6/22/15
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Broken shoulders, cracked knees and ribs -- could be an old rower as well as an old boat. Too bad we aren't as easily repaired. (I'm still not quite in need of repair -- just amused by the terminology.)
andymck...@gmail.com
Jun 23, 2015, 7:02:42 AM6/23/15
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On Tuesday, June 23, 2015 at 4:51:54 AM UTC+1, Ellen Braithwaite wrote:
> Broken shoulders, cracked knees and ribs -- could be an old rower as well as an old boat. Too bad we aren't as easily repaired. (I'm still not quite in need of repair -- just amused by the terminology.)
Hmm, maybe I'll just give the boat a few Ibuprofen, and tell it to rest a few days!
> Broken shoulders, cracked knees and ribs -- could be an old rower as well as an old boat. Too bad we aren't as easily repaired. (I'm still not quite in need of repair -- just amused by the terminology.)
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