35' cat concept for the inside passage.

well thats enlightening, so you guys would suggest some form of over the side launch as being preferable to aft launch. Hmmmm. I'd still want to store it on the aft deck for passages but I can see keeping it aside for everyday use.

So any good examples of boats with good access to side launching crew and passengers ? Seems like it would end up a pretty asymmetrical set up.

 

Prices I am getting in Oz have been :
Sliding side windows @ $1274 each x 2
Fixed side windows @ $960 each x 6
Triangular fixed side windows @ 650 each x 2
Fwd Facing hopper style windows (hinged strut supported hatch) $1160 x 4
Panel sliding door $2764 x1
or out-swing door $2287 x1

PLUS 10% GST

This was black anodised ally frame, dark marine toughened safety glass

I can taste sick in my mouth.

 

I would agree that boarding a monohull sailboat over the stern is awkward and it's much easier from the side.

But it's the opposite on a catamaran and most powerboats, which tend to have higher freeboard and transom steps/boarding platforms. Certainly I haven't seen anyone boarding a large catamaran from the side, and nearly everyone keeps their dinghy in davits aft.

BDWiley - I assume you are talking about boarding vessels at sea, not in harbour?? I agree though, getting caught under a catamaran bridgedeck is not recommended in any sea.

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

The eraser, or the Delete button is the second most used tool a designer has

As with any activity that starts with a blank sheet (music, books, even boats) you have to accept that you will throw away at least 30% of your ideas. (A commissioned design doesn't count as a blank sheet of course.)

So, despite what it might say on my website (soon to be updated), although my smaller powercats have asymmetric hulls my Skoota 36 has conventional hulls. The first is now building, in foam sandwich, and will be used as a charter boat in the Mediterranean

And to put the size of the design process into perspective, if you went to a designer with the ideas you had a month ago he'd probably get to the stage you are now in a couple of days. Yet it will around 3 months work for him to turn it into a design that can be built

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Yes, in the Arafura Sea which isn't (generally) a really rough piece of water. We used to board foreign fishing vessels to check log books & monitor the catch, get off the ship a couple of days later, which gave plenty of scope for a weather change. Getting on/off a 120' fishing boat is pretty easy as the IRB just rides up & down next to the hull which isn't moving much, you just have to time your jump.

It didn't take much swell to make maneuvering the dinghy dangerous when re-boarding our vessel. Even a 4' swell caused problems with the dinghy going under the aft end of the bridge deck or if the hulls were coming clear of the water, under one of those. We flipped a couple of IRB's like that, ended up trashing them.

Previously we'd used a monohull fishing boat and could launch/recover in far worse seas using the lee side.

I'd agree that there seems few other options for launch/recovery on most cats.

Just something to think about. Not an issue in calm waters like a harbour.

PDW

 

So this might have been you, had you been in the USCG???

5 USCG officers had no problem boarding our 35ft catamaran at sea in the Gulf Stream using the transom steps. We were sailing at 8-10 knots plus higher surfs, wind approx 20 knots NE

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

OK so I've been reading threads and there's a few things I need on my list of **** to include in the design of this thing, now that I've got some idea as to what I want it to look like, although I'm still working on it.

Positive flotation upright or inverted, I've got a plan for foam filled floors in the hulls and in the bridge deck making the thing unsinkable upright but whats the deal with inverted. I suppose I could go with the inflatable salvage type balloons on the "hood" ( roof ) rigged to go off when inverted but thats an automated system which could fail. So I'm more interested in something that ensures float upside down. And with a nice air pocket and dry place to camp out for a few days if necessary. So maybe a survival area in either hull would be nice.

no skid deck paint under the bridge deck, rope lashings access hatch multiple strobe beacons also all under the bridge deck, what am I forgetting under there?

Air supply to the survival area. Silly as it sounds you can't breath through a tube if its longer than x, you just don't have the lung capacity. So I'd need two snorkels and a air pump on one of them, hand operated. Or whatever the standard emergency mechanism is for getting air into the hull.

I need to include some capsize bulkheads, I'm assuming those are solid with there access ports on deck, rather than to the cabin or hulls. Enough to float my boat ;-) regardless of the foam fill in the floors, which doesn't help me any upside down.

I want my batteries on gimbals and out of the water if at all possible, so my safety areas can have light and radio on demand regardless of orientation.

It would be nice to be able to move from on hull to the other without getting wet as well, any ideas ?

and one probably silly one
Ideally I'd like to be able to jettison the engine from the inside. Might not be possible but it sounds good.

 

Keep researching
Start with showing me an example of a sizeable displacement powercat that has ever flipped.

Are you taking the piss now?

 

better safe than sorry, and I wouldn't consider 35' sizable? Is that really considered a cat of significant size? I'd have thought over say ~40 to maybe 45 would start getting into the range of a large cat. I'd think of 25~40 as midsized. But regardless I want an ultimately safe ride.

 

My point still holds
show me a 30 to 35 ft displacement powercat that has flipped
or do you plan on yours being the first one?

I'd suggest you get professionally designing done if you truly believe they can flip and wasnt the reasoning behind these slab sided flat bottom hullshapes that it was to be an "inside" Waterway vessel

 

Read the first part of this document from Lock Crowther for further information
This is from the great man himself and actual testing was done in support of the statements.



Full copy of design notes here including info on how to actually build.
http://www.cruisersforum.com/forums/f48/lock-crowther-design-notes-as-promised-5910.html

 

I said this before.

Don't ever worry about capsizing a large power cat. It's not going to happen. You saw the video of a sailing cat going through surf with the crew waving at the cameraman.

See here, a video of a fishing boat doing the same thing as that catamaran did. But with less success.

http://www.youtube.com/watch?v=Lku2Nzsq710&feature=related

to save time go to about 2min 50sec in

For sure a powercat is WAY more stable than any monohull powerboat. All naval architects will agree with that one.

As will those in test tank facilities (like the Wolfson Unit at Southampton University, UK) who have all failed to capsize model powercats in waves. Even though they easily capsized monohull powerboats.

I bet no trawler yacht owners think about capsize even though they know fishing boats capsize every winter.

And you're not going to meet conditions that cause even a monohull to capsize when chartering in the Inside Passage. After all, the most common vessels you meet there are kayaks.

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

My last post and sabahcat's were written concurrently

We both wrote about Lock Crowther's powercat test. I have seen the video from that test and it was very convincing evidence that powercats don't capsize.

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

side note, I'd also like to rig a two person parasail kite to the front of this thing and be able to sit in a chair and operate the control lines off a joy stick when I'm on my own and going somewhere. Like Hawaii or something.

I though the inside passage could get pretty rough sometimes?

 

Saba
way to fuzzy for my eyeballs to focus on mate. Must be a better resolution than that somewhere ?

OK time to make a new sketch