Adding vee to cat hulls

ABS offshore rules are not supported, since 1994.
But yes, other rules do not have any problems with secondary bonding.

Our cats are also built with secondary bonding. BUT there is one big difference: secondary bonding is done at yard, on dry boat that has never been in use, with proper materials and on specially prepared surface. Also we never locate the joints in highly loaded areas.

 

Some of secondary bonding samples:
http://albertnazarov.blog.ru/116418867.html
These cats will be joined at CL, but we use lamination plus bolted joint as it is highly loaded area. Joint is designed to LR SSC requirements.

The result will be:

 

Some replies below in red for visibility...

 

Now isn't that a commercial boat? Very different requirements from government bureaucrats than a simple cruising catamaran would have, no?

Bolting your secondary bonded keel joint is unheard of in the recreational catamaran market.

 

I was doing refit of sandwich 89' tri, built in NZ; it was on water for years. Even after 2 years on hardstand there still was moisture in foam in bottom and skeg.

 

Gotcha. That could be an issue. Guess it comes down to the specific boat and specific drying process and possibly removing laminates and drying before you start adding anything.

 

Yes, it is commercial boat built to class. And unlike ISO Small Craft, for these there are regulations on joints. This will also apply to yacht (L>24m) if built to LR class.

Actually the reason why we use this bolted/glassed joint is limited access from inside. I would say this is not bureaucrats, this is engineering.

 

Now imagine You are trying to dry the boat standing on the beach, in humid tropics with 80% of humidity. We opened problem areas but did not use heat gun.

 

On photos below, our 10m powercat is built of 2 separate hulls (made in temporary mould for one hull). Those are set into assembling jig and wet deck structure is formed. Inner sides of hull are under laminated; they are getting full laminate once they are in jig. This is all secondary bonding, but made on dry boat.

Similar process is here (upper photos), for 16m powercat:
http://albertnazarov.blog.ru/110334755.html

 

And a sailing snob I am - with no apologies

Can you list the boats/issues of Multihull World your sailing designs have appeared in? I'd like to read up on them.

 

LOL. No emotion here, just trying to get a question answered.

I agree and just wanted to be enlightened as to what it might be . IMO anyone who makes a successful career in boat design deserves to be commended - whatever type(s) they specialise in.

 

I concur about secondary bonding but the other way to look at things is having the crash advantages of a double skin on the bow.

 

On our website, 'Press' section > most of them are listed.

 

Yes and no.
Secondary bonding surely is allowed and it does a good job. However, primary bond would be stronger. But in either case it cannot be achieved here.
Leaving the original structere where it is, would at least not weaken the boat.
I reckon that Alik was more concerned about placing the joint in the region of higher stresses.

Unfortunately, building rules often ignore or even exclude multihulls - at least in details.
We presently modify a Schionning design (with help from other bright brains) to ISO compatibility. And sometimes meet white spots on the chart.

To make it clear:
Not that we do not trust Schionning's experience - we simply intend to upgrade and further improve.
..... Hi Brett .....

 

One other thought:
The boat really does not look well designed.
Why not sell the boat to a 'Rookie' and buy one that was done properly.

In project management we call this: OUTSOURCING

Pity the next guy, but on the other hand:
what is it good for if we continue to allow 'bad designers' to produce 'bad boats'.

This is not a joke: I once convinced a boat owner to stop putting his money into repairs. Instead, his boat was stripped and donated to a Kindergarten where it sat in the playground, causing much pleasure.
The owner bought a different boat and was very VERY happy with that one.