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View Full Version : Now here's a radical hull form



mmd
08-02-2017, 09:30 AM
https://keyassets.timeincuk.net/inspirewp/live/wp-content/uploads/sites/18/2014/11/SWATH-2_100pc.jpg

Flying Orca
08-02-2017, 09:31 AM
Purpose?

mmd
08-02-2017, 09:37 AM
Dang - I didn't want to get serious so fast. It is a SWASH hull (Small Waterplane Area Single Hull) and the general idea is to create a platform that is only minimally affected by waves, as the majority of the floatation hull is beneath the waves that would toss a conventional hull around.

Figment
08-02-2017, 09:39 AM
gotta be a harbor pilot boat, no?

AlanMc
08-02-2017, 09:41 AM
wait, is that a hydrofoil or will that main deck be out of the water even at full stop?

amish rob
08-02-2017, 09:42 AM
Dang - I didn't want to get serious so fast. It is a SWASH hull (Small Waterplane Area Single Hull) and the general idea is to create a platform that is only minimally affected by waves, as the majority of the floatation hull is beneath the waves that would toss a conventional hull around.

Oh, right. But I'M on drugs because I draw squiggly roller skate people. :)

Now you have to get really serious really fast and explain more.

Haha.

Peace,
Robert

John of Phoenix
08-02-2017, 09:42 AM
That would be huge hit as a work boat. I've seen conventional work boats tossed around like rubber duckies out in the Gulf.

http://sageintermarine.com/content/uploads/2015/01/2.jpg

willmarsh3
08-02-2017, 09:46 AM
Let me guess, it can't carry too much cargo or gear since the band of allowable weight appears to be rather small - too much and she sinks to her deck and gets tossed around quite a bit by waves.

Pilot boat?

mmd
08-02-2017, 09:58 AM
No, it is not a hydrofoil - it is a full-displacement hull, sort of. I thought it was a pilot boat, too, but there are pilot boat features missing - lots of bumpers and no railings at the deck edge are normal for the type. SWATH and SWASH hulls are not very good at carrying cargo because they can't cope with the variable loading. They are excellent at tasks that require very stable decks, such as oceanographic research and crew transport. Their Achilles heel is that they have deep draft for their size.

oznabrag
08-02-2017, 10:00 AM
That's nothing more than a Chesapeake Deadrise Skiff with a fancy coat of paint!

David G
08-02-2017, 10:03 AM
Love to see folks experimenting with hull forms. The successes are enlightening and make me smile. The (non-injury) failures are entertaining, enlightening, and make me grin. Any info on how this one is in actual use? It's certainly a fascinating contraption.

AlanMc
08-02-2017, 10:11 AM
guess it's not just a CAD file


http://articles.maritimepropulsion.com/image.axd?picture=2012%2F8%2F3.jpg

mmd
08-02-2017, 10:14 AM
Oz, you made me laugh out loud. My wife came to see what happened.

The article about the boat in the OP - designed by Abeking & Rasmussen - is at http://articles.maritimepropulsion.com/article/From-SWATH-to-SWASH-Further-development-at-AbekingRasmussen48124.aspx

Figment
08-02-2017, 10:14 AM
I wonder if the engine is down in that pod, or just a gearbox?

amish rob
08-02-2017, 10:15 AM
guess it's not just a CAD file


http://articles.maritimepropulsion.com/image.axd?picture=2012%2F8%2F3.jpg
OMG, the Kilingons are stealing our underwater drone! :)

Peace,
Robert

AlanMc
08-02-2017, 10:16 AM
https://www.mtu-report.com/Portals/_default/assets/0/1633/623_070512_Swash_8.jpg

Figment
08-02-2017, 10:20 AM
It seems that the bilgepump manufacturers have been lobbying the design firms rather successfully.

Flying Orca
08-02-2017, 10:21 AM
That's nothing more than a Chesapeake Deadrise Skiff with a fancy coat of paint!

You, sir, win one million internets.

oznabrag
08-02-2017, 10:23 AM
Oz, you made me laugh out loud. My wife came to see what happened.

The article about the boat in the OP - designed by Abeking & Rasmussen - is at http://articles.maritimepropulsion.com/article/From-SWATH-to-SWASH-Further-development-at-AbekingRasmussen48124.aspx


You, sir, win one million internets.

Thank you, gents!

Every once in a while . . .

mmd
08-02-2017, 10:36 AM
But I wouldn't describe you as a blind pig, Oz. Really. <grin>

Figment, engine placement is mostly related to size - big SWATHs have the engine in the pod, smaller ones (due to space constraints) have it/them on deck level. Many years ago (1980's) I worked on a design team creating design exercises for large (300 - 400 ft LOA) SWATH ships for military use and all were designed with engines in the pod. I also did some minor design work at that time for the CCGS Frederick G. Creed (pictured below) which had its engines at main deck level.

https://upload.wikimedia.org/wikipedia/commons/8/8d/Creed2.jpg

John Meachen
08-02-2017, 03:55 PM
I haven't seen one of the tris,but I have seen one of these.

http://www.ocean3.fr/upload/tinymce/Equipements_Pilotines/Pilots_NL_01.jpg

I'm curious as to whether they behave as the promoters would have us believe.

mmd
08-02-2017, 04:02 PM
In my very limited experience (one day-long trials cruise on the CCGS Frederick G. Creed, I say yes. I observed a water glass filled to within a quarter-inch of the rim sitting on the flat top of the helm console while underway at twelve knots in 1.5-metre (5-foot) waves for twenty minutes and nary a drop was spilled.

Edit to add: This video is blurry, but clear enough to see the differences in their relative motions in a seaway...


https://youtu.be/Xg6xyAKJOtE

J.Madison
08-02-2017, 05:33 PM
The catamaran seems the smart way to use this idea. With the tri, there just seems to be no reserve buoyancy if something really big does try to roll the vessel.

Peerie Maa
08-02-2017, 05:38 PM
The catamaran seems the smart way to use this idea. With the tri, there just seems to be no reserve buoyancy if something really big does try to roll the vessel.

On the other hand, a tri will survive damage better.

BrianW
08-02-2017, 10:16 PM
In my very limited experience (one day-long trials cruise on the CCGS Frederick G. Creed, I say yes. I observed a water glass filled to within a quarter-inch of the rim sitting on the flat top of the helm console while underway at twelve knots in 1.5-metre (5-foot) waves for twenty minutes and nary a drop was spilled.

Edit to add: This video is blurry, but clear enough to see the differences in their relative motions in a seaway...


https://youtu.be/Xg6xyAKJOtE

Great video!

I was thinking more along the lines of lateral stability with the outrigger/tri-hull design, but the lack of bow dipping, and plowing into oncoming seas in the longitudinal axis was impressive.