I'm trully sorry if I caused all this, Gary.

Would I be correct if I assume you reinforced the outside of the hulls but not the insides ?

Bloody bad luck, Gary.

A real pitty.

>>hope you guy's don't mind a sad post.

Surely not, this is drama. There wouldn't be any exitement if there is no risk of failure. This time, the risk won out over good fortune. But I for one have heaps of respect for you for starting on an adventure like that. You're my hero. I remember running heaps of numbers on the basic Taipan platform to determine the right modifications. I remember the feeling during the first times out on the water. I understand the greatness of the project you choose to undertake.

Together with the others I hope she is salvageable. This project has trully won the hearts of the sailors on this particular forum.

If I may; I've you choose to repair it and the failure was on the unreinforced inside of the hulls than I would advice you use the same cloths for the reinforcements as was used to build the hulls. Using a different cloth can still lead to problems as, for example, glass and carbon have different properties leading to staged failure. Meaning first the stiffer carbon will fail as the more flexible glass will not take any load at that time. Then all the load on the glass again, which will fail in sequence. Using the same material for the reinforcements is a good way to prevent that. I'm sure you know this yourself but I just wanted to make sure.

But again Gary, bloody shame this happened.

Hope you will rise from the flames and get altered back, with you in the saddle.

Wouter

Oh NOOOOO !!!

Sorry to hear the news Gary.
I saved all the pics of her on my pc, and look at them often. You just HAVE TO FIX her ! (I know it`s easy for me to say that when you have to put all the money & hard work in, but I really hope you get her back out there soon.)

Good luck,
Steve

Whoa. I know you Australians have quite the sense of humor, and I've had my leg pulled more than once by you guys. So, I'm just wondering if this is really true--did Altered really meet demise?

It sounds as if you need to open the hulls and glass in a relatively light "sub deck" approx' a third of the hull depth down from the deck extending from approx' the shroud mounting point through to the main bulk head under the front beam and then continue it on in front of that bulk head for approx' 600mm forward. This wiil allow the loads generated by the bridle "pulling" the bows together and upwards, and the similar loads caused by the sides way water pressure on the lee ward bow.
As an "A" class these loads would have been minimalised by having a "high" bridle and only one very high aspect mainsail creating only a minor amount of the loads that you are now experiencing, but what you have done when converting to an F16 is to dramatically increase the collective "inward and upwards" loadings on the inside of the hulls forward of the front beam. The front beam/bulk head act as the privit point for those forces and just the "skin" of the hulls with out any structural disipation of those loads will result in this type of failure.
The sub floor does not have to be of any great strength or weight, as it "assumes" much more strength than its own construction would sugggest by its engineering in place.
I know its a set back BUT the man who never made a mistake never made anything, and this problem is relatively easily surrmountable

Gary,

My sympathies. Thanks for taking us along for the ride. Beautiful work! Hope you find a way to revive her.

In any case, thank you so much for sharing with the world.

GARY

Gary,
I'm very sorry to hear about your minor setback.
But unless the failure is catastrophic this is just a minor set back and a good opportunity to make those hulls bullet proof.
I agree with Darryl's post entirely.

However you eventually decide to affect the repair consider the two main problems would be column failure on the inside hull side between the bridle and the main beam and ripping the bridle fitting out because there is either no bulkhead at the bridle or a bulkhead that is not designed to take the bridle type loading.

If you have not already formulated a repair plan I would like to make the following suggestions to get you thinking.

Given the hulls cross sectional shape I would cut the hull open from the bottom near its widest point. This will give you good working room.

I would cut a section out between a little forward of the centre case (200mm) and main beam bulkhead leaving a good section in place around the main bulkhead.
This will save having to disturb the bulkhead and will allow the remaining section of hull to keep the sides true.

If possible I would leave another section in place half way between the main beam and bridle. The cut would stop a little short of the bridle but close enough to put in a bulkhead and secure the bridle fitting to it. if one isn't already there.

If the hull has just delaminated repair would be quite simple. Inject resin and through bolt or screw with slightly flexable plates either side to apply pressure.

Personally I would then dril the inside skin at intervalls and inject resin around where the sub deck was about to be fitted.
To securely tie the two laminates together.
Glass in the sub deck from near the bridle to back past the main beam.
Relacing the panels that have been cut out is quite simple.
You can make up a fibreglass plates to form a lap bond on the inside and once the panel is bonded in place grind a taper into the outside laminate and glass that back together.

Even with now stronger hulls you might like to consider the height of your bridle.
The lower the bridle the higher the loading on the inside hull wall between the bridle and main beam and inwards loading on the bridle fitting.

You could even go to a system similar to marstrom are using on the M18 and M20 but without the carbon tubes. Instead use a line from the mast to the pole around 1.5m up from the mast base to behind the shuffer.
This line can also help give positive rotation to your mast.

Having said all that most problems have more than one sollution. In many cases it just gets down to personal preference.I have done nothing more than express my preference in the hope that it gets you thinking if you have not already started.

Once again I would like to stress the importance of looking at this as an opportunity to make the hulls bullet proof.

This experience will make every win in the future all that much sweeter.

Good luck.
Regards,
Phill

Hi all,
you guys are unreal thanks for the support. This realy does feel like a community of sailors, certainly makes me feel better.

Still don't know what I am going to do with Altered will be getting it looked at by others this weekend, I am still going to take it to Colac, am sure I will get lots of expert? opinions but there will be at least one boatbuilder there with experience of this kind of repair. I hope to get it fixed by a boatbuilder, as I just don't have time available now. If I can't get it fixed by boatbuilder I will be in further touch with Darryl and Phil there expertise is much appreciated.

Regards Gary.

Gary,

Phill has some great techniques for the laminate and core repair. The break sounds typical of a catamaran hull failure though. A compression failure in the hull just forward of the front cross bar. A-cats are very light and not designed for the loads that would come from a sloop bridal forestay set up. Composites are very poor in compression. Carbon is one of the worst fibers for this as well, mainly because you use carbon to go light, giving very thin skins to your hull laminate. Thickness is the key to good compression resistance.

Given that the A cat probably was able to get away with not having to have a false floor as described earlier, you could most likely add the additional reinforcement needed to comensate for the added compression loads on the deck alone. Bonding an additional layer of core to the existing deck, then laminating and fairing the new top surface would drastically improve the comression taking ability and if done with the same skill shown in your other work, you would not be able to tell anything was done. This would be a lot easier than opening up the unbroken hull to place a sub floor.

Just a thought, Good luck in getting back on the water soon.

Matt

Maybe I missed something here...

The photos show you sailing uni-rig...no jib. So why did you lower the bridle union from the original high-bridle of the A? Is it to allow stabilizing the spin pole and mounting your cool blue triangular snuffer mouth? The F18HT uses a high-bridle and is snuffed mid-pole. And remind me whether F16 is uni with spin or sloop-spin (jib and spin)?

Did you ever run it with a jib?

David, Matt

The same thoughts occurred to me as well.

First the Bridle seems a little low to me as well considering the hulls were modified A-cat hulls. Personally (as I didn with my own boat) I would have raised the bridle intersection and used a extra 3rd line to keep up the blue snuffer mouth. In altereds case I would have placed the bridle strop some 2 mtr's up from the decks and have it then continue as a single stay.

Having double forestays is not what you want to have on a spi boat as the spi tends to get blown between the stays to often. A single forestay with a high bridle strop seems to be the best compromise.

David. F16 is both sloop and uni-rig. We sail sloop when doublehanding and uni-rig when singlehanding. Gary only sails singlehanded as far as I know and has no jib as a result.

I agree with Matt that the most simple reinforcement against the most likely cause of the failure would be to just laminate an extra skin to the outside of hull that is just inside and in front/below the mainbeam. The failure seems to me to be a compression buckling failure caused by the increased bending stresses due to the bridle strop. You probably have added 400 kg sideways load to the hulls = ALOT.

The fibres can probaly take the laods but not if they become unstable when the hull starts to get out of colom (rimples along the hull) and moves sideways inward and/or outward. Thickening the wall will prevent this rimpling effect and thus induce more strength than would be expect by just adding the cloth.

But we need to be sure that this failure under compression buckling was the case of this. A sub deck is the most effective solutions as that would completely stabilize the walls.

Get up back there on that horse Gary !

Wouter

Hi all,

thought I would give you an update on Altered. All has finaly been sorted out and boat is being fixed and strengthened by McKenzie Composites as we speak, hope to be back on the water in a few weeks. Bigger better stronger etc. Can't wait to get back on the horse Wouter.

Hope to be racing end of January long weekend in OZ lots of sailing on, maybe even in South Australia, Phil what to you think of Milang Goolwa?

Febuary is looking very busy possibly travelling interstate for reggattas every weekend. Still working on trailer to make sure it is up to scratch.

Anyway hope you all have a good christmas and a happy new year, thanks for your support through the good and bad times with Altered.

Regards Gary.

From you I expect nothing less !

Happy X-mas and best wishes for 2005 to you too

Wouter