Oyster Problems?

[poiu]

Originally Posted by transmitterdan

I particularly liked the self tapping screws for the hull/deck join. That was impressive....

I thought those screws were the sort I would use for attaching my baseboards, not a boat deck.

No screws/bolts/tabbing on the bulkheads though, they missed that out conveniently, just precision robot applied glue.

I didn't see any liners also; nice bit of editing.

[robert sailor]

Originally Posted by poiu

I thought those screws were the sort I would use for attaching my baseboards, not a boat deck.

No screws/bolts/tabbing on the bulkheads though, they missed that out conveniently, just precision robot applied glue.

I didn't see any liners also; nice bit of editing.

I think plexus is pretty decent on gluing fiberglass together but I'm not as convinced on bulkheads. If the bulkhead is 3/4" plywood you have a surface of 3/4" to take the ongoing loads. If you compare that to the stick built boats that use fg tabbing you are spreading the load over 8" or so which is a much more flexible and stronger system, at least in my mind. Plexus is a very strong adhesive but it is not always the best solution although it is always the cheapest and easiest one.

[Polux]

Originally Posted by sailorboy1

I see the Indians are circling

How stupid can they be on Bavaria? they take great pains to advertise and actually show how their boats are built just for some to find they are badly built

Wait a minute these guys that think Bavarias are badly built are not the same guys that ignored that robotics were used on the marine Industry?

Some that sail them have a lot of confidence in them and the way they are built sailing in rough weather and crossing Oceans and on the smallest of the Bavarias. There are people that will never learn

https://www.youtube.com/watch?v=F38EDfEGrS8

[jmaja]

How many Bavaria deck hull joints have failed? Or even leaked? There are many expensive boats using glued joint as well (X-Yachts?). The screws screw into wood under the mating surface of the hull and are used to press the glue while curing.

Bavaria tabs the bulkheads (and most interior parts) to hull, but not to deck.

[poiu]

Originally Posted by Polux

Wait a minute these guys that think Bavarias are badly built are not the same guys that ignored that robotics were used on the marine Industry

The use of robots in industry is a theme that for years has had connotations of advanced methods and engineering sophistication. I think many have fallen for the hype.

Robots are used in fact for many other reasons. Cost cutting by removing labour and de-skilling production processes are the usual justifications for the heavy investment. Often it is done regardless of cost to circumvent labour shortages. Sometimes for prestige. Way down the list of justifications manufacturers deploy is to improve the product. I believe the thinking at Bavaria has not much to do with quality. I can't see how they could really help with quality here.

[Polux]

Originally Posted by jmaja

How many Bavaria deck hull joints have failed? Or even leaked? There are many expensive boats using glued joint as well (X-Yachts?). The screws screw into wood under the mating surface of the hull and are used to press the glue while curing.

Bavaria tabs the bulkheads (and most interior parts) to hull, but not to deck.

Hi performance bonding agents are not the problem they are used extensively with success in many high profile industries, from space industries, cars to engineering structures in buildings and bridges.

The problem when exists is due to the way they are (wrongly) applied and it seems not to be clearly this case.

[transmitterdan]

Structural adhesive bonds are used in spacecraft and aviation. But they are heavily engineered and tested to destruction many times before being certified for flight. The adhesive fastening is sometimes stronger than other fastening but usually the motivation is weight or size not cost.

The Bavaria hull/deck glue is just for cost savings. It is not "stronger" than traditional hull deck joining systems.

[neilpride]

Honestly, they plexus the joint, as far I know with time we see if they hold well or not, I see in a couple of occasions that joint cracked when I'm working in a leaky stanchion... not sure if is just cosmetic or the crack is serious but then I wonder if you misplace a fender and hit a hig dock , for sail to weather with the rail in the water I put my money in a troughbolted deck , but just me..

[Polux]

Originally Posted by transmitterdan

Structural adhesive bonds are used in spacecraft and aviation. But they are heavily engineered and tested to destruction many times before being certified for flight. The adhesive fastening is sometimes stronger than other fastening but usually the motivation is weight or size not cost.

The Bavaria hull/deck glue is just for cost savings. It is not "stronger" than traditional hull deck joining systems.

Hull deck joints are traditionally bonded, some use screws too. Old deck joining (before superior bonding agents era) were made other way, probably with worse results.

It seems you agree that the problem are not bonding agents, that can have a superior performance, but the way they are used. It seems to me that Bavaria is using them in a proper way, using screws to be sure the bonding is tight.

[robert sailor]

Originally Posted by jmaja

How many Bavaria deck hull joints have failed? Or even leaked? There are many expensive boats using glued joint as well (X-Yachts?). The screws screw into wood under the mating surface of the hull and are used to press the glue while curing.

Bavaria tabs the bulkheads (and most interior parts) to hull, but not to deck.

If they are not tabbed into the deck there will be lots of flexing going on sailing in larger seas. My first offshore boat was a C&C 36 and it was built the same way. Coming back from Hawaii we got into a good gale and the head door was moving up and down close to an inch.
Sold that boat bad bought a CS 36 which was glassed all the way around and there was no comparison between the two. No matter the sea way you could open and close the doors on the CS and they would fit perfect. On the C&C often you couldn't close the door unless you timed it, lol.

[Exile]

Seems like I often hear or read about 5200 and thru-bolting used for the hull-deck joint. I know mine is thru-bolted, and wouldn't be surprised if 5200 was used. I guess Plexus and other modern adhesives are now considered superior, but hard to know if thru-bolting is now unnecessary or just more expensive.

[robert sailor]

Maybe have a look see into what the the lower volume, higher quality builders are doing, I'd be real surprised to find any of them using Plexus and self tapping screws in their hull to deck joints.

[robert sailor]

C heaping out on the hull to deck joint has been going on for years and while screws and plexus might not turn your crank it is sure lots better than Catalina's shoe box joint or the pop riveted joint used on the Whitby 42.

[jmaja]

Originally Posted by robert sailor

If they are not tabbed into the deck there will be lots of flexing going on sailing in larger seas.

You can't tell that just from not being tabbed into the deck. You can easily design a structure that doesn't need a bulkhead at all.

Originally Posted by robert sailor

Maybe have a look see into what the the lower volume, higher quality builders are doing, I'd be real surprised to find any of them using Plexus and self tapping screws in their hull to deck joints.

My previous boat was a "lower volume, higher quality" boat and it's deck was only glued to hull. No screws nor bolts, except for the chainplates which were bolted through both the hull and the deck. It also had no bulkheads expect for the toilet walls (besides companion way) and lockers (only up to side decks). Those were not tabbed to deck. It was a very stiff hull.

I haven't examined in detail, but it looks like current X-Yachts have a glued hull deck joint. I don't know if you consider it "lower volume", but I think most would consider it "higher quality". They used to be bolted, but not any more.

I can't really see why there would be a need for bolts in the hull deck joint. Certainly a well prepared glue joint with a proper glue is much stronger and stiffer than bolts at 100-200 mm spacing. There is a huge area for the glue, when deck and hull overlap for a couple of cm.

[robert sailor]

Yes you can design a structure that doesn't need bulkheads but the Bavaria is not one of them so what's your point? Personally I don't have a problem with glued joints as long as they are designed and built well. Who was the yacht builder that built your last boat?