Sinking Cats

[Canibul]

Is that a catamaran??

[cat man do]

Originally Posted by Laidback

CMD = Spot On !!! *****

What makes you think it has no probs with fuel?

It carries 45,000 litres of fuel

Or is that your point, it is a supertanker?

More pics here easier than the previous one I had linked to
http://www.designboom.com/weblog/cat...es-yachts.html

[sctpc]

funny looking cat!!!!

[schoonerdog]

I knew Simon Slater well who designed the PDQ 44. I remember it needed a lot of freeboard.

From the picture the builder is kneeling in the engine compartment, it looks about 4 ft deep or so. I'd guess the keel sticks another 3 feet below that and typically people don't want their engines below the waterline, so I'm guessing that about 2 ft of that compartment is below the waterline. So with cabin sole, plus say 6' 4" of headroom above I'm guessing that the decks are some 8 1/2 feet above the water? Are the hull soles above the waterline? If you seal that engine room access with a water tight hatch it would provide a LOT of reserve structural bouyancy. I remember talking with Simon about the depth the PDQ 44 would sink with a hole amidships (pretty much the worst possible place). With all of the structural bouyancy I think it would only sink about 18 inches or so, compared with most catamarans that have their bows sticking up and be awash in the aft section (or some of the heavier ones that would just sink sideways). Kanter at the boatshow would go through the Antares and show all of the structural bouyancy fore and aft and keep remarking "this is great, no one else does this now".

Originally Posted by downunder

Freeflow 46 is one

New design , 1st currently under construction by one of original lightwave catamaran owner/builders. Will be a big 46 equilivant to many 50 ft cats. Flat panel/infusion. all weight central so should have good stability.

8000kg - up to 11900kg design.

Freeflow Catamarans

Atached photos of a hull shoe out still in mold. All tanks/motor(shaft drive 2 degree shaft angle/ under hull sole.

[downunder]

Schoonerdog

There are some similarities with the Antares and Freeflow although I believe the Freeflow could be consigered in the next generation of cats just coming on to the market.
Modular, can be supplied as a kit, infused foam, flat panel, load capacity with good performance and built for tropics.
If you look at attached photos of hull shere mold under construction note the line in hull that indicates water line and is at cabin sole level. Motor and tanks are under sole as per previous photo. Note in the photo from the stern the small mini keels below the hull shoe mold and how stern lifts to accomodate and protect low angle shaft drives and rudder with minimal increase in draft.



Can't see deck more than 2m (around 7ft) off water.
I will start a new thread on Freeflow catamarans so as not to highjack thread

[sarafina]

...sorry, sorry, my bad I just couldn't help it... been thinking this every time I see the thread!

[downunder]

photo missing from post #170 above

[downunder]

sarifina,

You are tough on your cat.

[Canibul]

Originally Posted by sarafina

...sorry, sorry, my bad I just couldn't help it... been thinking this every time I see the thread!

[schoonerdog]

I guess I'm just thinking of this from a pure math point of view. You have 6' 4" of headroom in the hulls for a lot of modern cats. You have an engine compartment sitting below that, which will extend another 3 to 4ft down, you have some sort of mini keels below that or perhaps a ft or so.

That means the hull of the boat from the bottom of the keel to the top of the deck is about 11' 4". You'll need a typical foam sandwidth resin infused about 1" thick in the deck and the cabin sole for rigidity, so about another 2" to this, so up to around 11' 6" So then it's a question of waterline. If you have draft of 4 ft, then the decks would be about 7' 6" or so above the water.

Do you have a line drawing of the boat from the side that shows the layout and waterline?

Originally Posted by downunder

Schoonerdog

There are some similarities with the Antares and Freeflow although I believe the Freeflow could be consigered in the next generation of cats just coming on to the market.
Modular, can be supplied as a kit, infused foam, flat panel, load capacity with good performance and built for tropics.
If you look at attached photos of hull shere mold under construction note the line in hull that indicates water line and is at cabin sole level. Motor and tanks are under sole as per previous photo. Note in the photo from the stern the small mini keels below the hull shoe mold and how stern lifts to accomodate and protect low angle shaft drives and rudder with minimal increase in draft.



Can't see deck more than 2m (around 7ft) off water.
I will start a new thread on Freeflow catamarans so as not to highjack thread

[Jetexas]

I thought the guaranteed way to sink a cat was to put some rocks in the burlap bag with it ...

[zeehag]

Originally Posted by sarafina

...sorry, sorry, my bad I just couldn't help it... been thinking this every time I see the thread!

so do i and i love kitties...LOL

[downunder]

schoonerdog

If you look at post #172 the photo shows a line about 10 inches down from the top of the hull shoe mold wiich is the designed loaded hull waterline (to give a straight line for painting waterline).
Motors below this. Small mini keels are on ground below the hull shoe at end of arrow.
draft 1.2m same as FF44. Hull sheer line around 7ft.

[schoonerdog]

OK, so I'm going to pull this back to the original topic then. Does your boat have it's hull cabin sole or floor (part you walk on) above the waterline? If so, then you could very easily have a very unsinkable type catamaran if you had the compartments below the waterline all with water tight hatches. Any hull breach you had would have water ingress only into those water tight compartments (such as your engine compartment) below the cabin sole and be fairly contained. With my boat (and most cats) a hull breach would result in water flowing inside the hulls, up to the waterline of the boat and then continuing in that compartment until offset by the structural bouyancy of the other watertight parts of the boat. With a boat whose cabin sole is above the water line and had many watertight compartments below the cabin sole, potentially it could have a hull breach and no water would be able to ingress into the liveable spaces. But it would have a very high sheerline.

[downunder]

Schoonerdog,
I don't currently have a vessel but am researching what is available and your point is great re sinking cats.
One of the vessels I am considering is the new FF46 the 1st of which is underconstruction due in water around October 2010. follow the website link here http://www.freeflowcatamarans.com.au...reeFlow46.aspx
New pictures available. As you see there will only be the possibility for water ingress into the motor and shaft compartments as the tank and other compartments are sealed. Lightly loaded or 1/2 tank capacity I imagine the sole will be above waterline.

With hulls and all vessel infused foam construction it will be unsinkable. As vessel construction continues I will watch this. Lightly loaded I don't doubt the sole will be above waterline. As you suggest shereline could be raised to ensure this. Will raise this with builder at Santuary Cove boat show.
cheers