SWATH Wind Farm vessel

Can't resist tootin our horn a little...this little 26m SWATH was launched, trialed and delivered early this year and is already "making waves"..

Vessel designed by forum member who I won't name without permission...but I expect he'll pop in. ;-)

http://www.offshorewind.biz/2016/11/10/mcs-swath-1-outperforms-other-ctvs-working-on-owf/

 

AH, but don't they say that the proof of the pudding is in the eating? AH, that saying is so true.

That is one top-class and cutting-edge vessel indeed, which testifies the top-class technical quality and capabilities of our forum buddy. Which is nothing new, after all.

 

I was on hand when she was first put to work. Initially there was a fair amount of pushback from the farm operators..."too big" (she's a bit longer overall than the vessels already working), "too heavy" (she's not, actually, any heavier than numerous of the other transfer vessels) and so on.

And then she went to work, finally. Blew everyone away.

 

Congrats, and what is the purpose of the white pillars on the deck? Very pretty boat, too.

 

Engine room air intake and exhaust. The engines are high up and forward..easily accessible, especially when compared to some other SWATH designs that have the engines down inside the main hulls.

A short video here:

https://www.youtube.com/watch?v=TSb18xKh2DU

 

You gave the name away by posting the link...

 

Very cool Bill! Thanks for posting.

 

Thanks Chris. This one is the first with our new zero-speed motion control for SWATHs; and of course includes the standard suite of SWATH stabilization gear otherwise.

More to come..including integrated stabilized transfer brows and gangways.

 

What is the effector used to accomplish zero-speed RCS?

 

The fins...leveraging the same basic impulse principle as is used for the now-ubiquitous zero-speed/on-anchor roll control for yachts.

 

GA for this vessel

http://www.adhocmarinedesigns.co.uk/wp-content/uploads/2012/07/SH-24-02-GA-05.pdf

Chris

 

Very cool and interesting boat, thanks for sharing.

What is the difference between a SWATH and a Catamaran type boat?
I know nothing about SWATH boats. Is it the shape of the hulls or other aspects of the design?

I have only seen pics of a couple SWATH boats and they had four pylons instead of two continuous type hulls.

Cheers, Allen

 

The clue is in the acronym. A swath stands for:

Small
Waterplane
Area
Twin
Hull

Put all together one gets S.W.A.T.H., or commonly termed Swath. The clue is the first 3 letters

 

Now that you made me think of it...
I've always thought that submerged torpedo-like hulls are the main distinctive feature of a SWATH, and that the small waterplane area is a consequence of having the biggest part of the volume displacement in the torpedoes.

But if, on the contrary, the main feature of a SWATH is the small waterplane area, then where does a catamaran end and SWATH start? Is there a rule (of thumb or some other body part) which says: this is the red line - up till here it is a very slender cat, from here on it is a SWATH?

 

Yes there is

And it is ostensibly a measure of the vessel restoring force.

For a swath there are several rules of thumb, but basically if the waterplane area, Aw, divided by the displacement to the power of (2/3) is less than 1.5 it is a swath. Another simple one is if Aw< 2xDispl^(2/3) ...basically same thing.

What you will fidn is that big ships like the QM2 and small sailing dinghies all have their Aw/Displ^(2/3) WPA-Ratio around 5-6. The so called-semi-swath is just in name only. As there is no such thing as a semi-swath. Can you dig a hole...yes...can you dig half a hole..??!! Either is it a hole or it is not. Either it is a Swath or it is not. The hydrodynamics don't lie! Thus semi-swaths are in name only....because in reality if you check their WPA-ratio it is around 3.4-4.0....way way off being a swath. They should be called semi-catamarans or just slender hull catamarans, nowt else.

But hey those guys in sales and marketing will call anything semi-something if it gets them interest