randii
Member
James did a post-mortem walk-through that was really interesting:
Zingaro Wreck Follow-up: 1984 Crowther Spindrift
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randii
Member
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As an owner of an epoxy-composite catamaran, I have more than passing interest in other... er... well... plywood boats (mincing words for best insurability).
I'm not interested in a trip to Hawaii, my tastes run more to coastal cruising, but it was still interesting to see the post-mortem walk-through.
I was pleased to see that much of the wood was in great condition... and that there were some out-of-plan cuts and bolts that focused loading. Seems like Zingaro held herself together well, for the most part, but her miles eventually caught up with her in heavy usage.
I'm not interested in a trip to Hawaii, my tastes run more to coastal cruising, but it was still interesting to see the post-mortem walk-through.
I was pleased to see that much of the wood was in great condition... and that there were some out-of-plan cuts and bolts that focused loading. Seems like Zingaro held herself together well, for the most part, but her miles eventually caught up with her in heavy usage.
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toolbar
Member
Very interesting (and scary) video.
Paul
Paul
boardhead
Anarchist
Still thinking wood is perfect for building trees!
Rasputin22
Rasputin22
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Boat was a veritable Petri dish!
boardhead
Anarchist
That’s what happens when you soak dead wood in water for a while!
KC375
Super Anarchist
It seemed there may have been a design issue and some ill conceived modifications / weakening of the structure BUT the biggest failure was glue failure rather than wood fiber failing.
Was the wrong glue used/wrong grade of plywood?
I’ve always had a soft spot for plywood boats...I’m now thinking that soft spot must be between my ears.
DtM
Super Anarchist
It had lasted a long time (and a lot of miles) before it finally failed. Maybe there should have been more ongoing maintenance.
it must have been a damp boat inside looking at all the mould. The moisture content of the timber was also possibly very high leading to glue bonding failures in multiple places. I would like to see where the chainplates are so we can consider the rig forces involved and the bending loads on the hulls leading to the failure.
Russell Brown
Super Anarchist
Yep, and I still think it's perfect for building boats. Wood boatbuilding technology has improved just as fast as any other boat building material. I trust the stuff more than anything else, so stick it!
MRS OCTOPUS
Anarchist
The vessel is rigged with inline spreaders.
Chainplates are bolted to packers on main beam just outboard of the bridgedeck cuddy cabin sides, well inside of extreme beam.
The chainplate bolts are visible well inboard of cracked area at 18:05 aprox. on walk through video posted above. ( just behind sail lying on bunk).
That looks one nasty, modified, poorly maintained boat .
The bulk head cut outs (door ways) look like they have been enlarged a little over the boats life to make liveability a little easier, and the only tools
at hand for the job was an axe. ^_^
I'm surprised it lasted so long.
I suspect it was cheap.
For good reason.
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We looked at purchasing Zingaro about 5 years ago. Beautiful cat, well maintained but some things that put me of. The hulls are Airex and the rest of the boat was marine fir ply I believe. What I didn’t care for was the ply wasn’t encapsulated, had a layer of glass on one side and the other side was bare painted fir. Probably not a disaster for most parts of the boat except the bridgedeck. The bridgedeck was fir ply that was glassed on the inside and just painted on the bottom, fully exposed to the ocean. It appears from the video that the hull to bridgedeck tabbing has broken loose at the bridgedeck and pretty much remained intact on the hull. Just a theory, but if that tabbing released would it put undo stress on the beams possibly causing the damage they received?
The Mad Hatter
Member
I think the major problem with wood boats is not the wood but the builder. A couple of simple rules have always worked for me.
The wood has to be dry and when the resin is applied the wood needs to be cooling and not warming up unless applying a vacuum. All fixing holes need to be oversized and filled and then re drilled with a smaller drill to keep a healthy layer of thickened epoxy between the moisture and the wood. I also like putting a light layer of glass over it to stop the grain from opening up and letting moisture in on areas exposed to the elements. It is a very easy material to work with and for this reason may attract builders that just don't have the knowledge/experience to do it right.
Don't blame the wood, blame the builder.
The bridgdeck to hull connection was very suspect. Just a light layer of taping, not very wide. And it was a 90 degree corner not a curve or chamfered panel.
That's a pretty highly loaded connection area and it wouldn't surprise me that it started failing there. But the structural damage was so extensive it was clear that it didn't have a lot of structural redundancy either. And the post build cutouts/modifications were bad. As was the wet wood in key areas.
They were lucky.
That's a pretty highly loaded connection area and it wouldn't surprise me that it started failing there. But the structural damage was so extensive it was clear that it didn't have a lot of structural redundancy either. And the post build cutouts/modifications were bad. As was the wet wood in key areas.
They were lucky.
Russell Brown
Super Anarchist
Thanks Hatter. You are more articulate and polite than I am. I have only built in wood/epoxy and composites, but at this point I'm really in love with plywood, lumber, and epoxy and really sick of composites. I have done most levels of composite work and I've grown to really dislike the materials and the waste generated. The only thing you failed to mention is the very forgiving nature of wood/epoxy from an engineering aspect. Things that shouldn't work can work. Under-engineered or under-built structures can be surprisingly strong and long lasting. I don't pretend to know everything, but I really like wood/epoxy boats.