Announcements
New Discussions
Trip to TX SPI or CC in Early Oct
by Banzilla. 07/05/21 11:17 AM
Previous Thread
Next Thread
Print Thread
Rate Thread
Hop To
Page 2 of 3 1 2 3
Re: Bow design Theory or Looks? [Re: DennisMe] #186390
07/28/09 07:43 PM
07/28/09 07:43 PM
Joined: Feb 2009
Posts: 678
Palm Beach County
TheManShed Offline OP
addict
TheManShed  Offline OP
addict

Joined: Feb 2009
Posts: 678
Palm Beach County
Bow view and stern view. Remember this is the roughed in foam


Attached Files
Copy of P10100a41.JPG (259 downloads)
Copy of P10100a28.JPG (255 downloads)
Bow View TMS-20

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

-- Have You Seen This? --
Re: Bow design Theory or Looks? [Re: TheManShed] #186392
07/28/09 08:19 PM
07/28/09 08:19 PM
Joined: Feb 2009
Posts: 678
Palm Beach County
TheManShed Offline OP
addict
TheManShed  Offline OP
addict

Joined: Feb 2009
Posts: 678
Palm Beach County
Few more views with side laying flat. It's about 3 feet tall for an idea of the size

10762
10763

Attached Files
Copy of P10100a47.JPG (244 downloads)
Front view of bow on side
Copy of P10100a51.JPG (243 downloads)
Angle looking from bottom of hull towards side from bow position.

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Bow design Theory or Looks? [Re: Don_Atchley] #186396
07/28/09 09:13 PM
07/28/09 09:13 PM
Joined: Mar 2008
Posts: 201
Adelaide, South Australia
simonp Offline
enthusiast
simonp  Offline
enthusiast

Joined: Mar 2008
Posts: 201
Adelaide, South Australia
Originally Posted by Don_Atchley
Sailing Math

Lots of spray = lots of energy wasted

Lots of energy wasted < Looking Cool

Therefore:

Looking Cool > lots of energy wasted

And so furthermore:

Lots of spray = Looking Cool, and cancels out any concern for energy wasted


Love it!

The stingray has to be one of the coolest cats around then.
Not only does it have the tornado bow, but also a front beam. When the front beam touches the water at speed it produces a very spectacular cartwheel. And cartwheels are cool too right?

I remember my amazement at how the Nacra 5.8 handled differently to the stingray. Whereas the the stingray would go up and over the wave. Mostly. With enough wind the 5.8 would just say F#$% ^#F, and go straight through, just like a wave peircer should i guess.

Then moving to the Taipan, I found that it would slice through those waves so easily compared the 5.8.

I cant be sure, but I think my current boat, an ozBlade, needs a bit more energy than the taipan, but much less that the 5.8, to get through a wave. If it does dig in though, it definitely recovers much easier than both.

Last edited by simonp; 07/28/09 09:14 PM.

Simon
BLADE F16 AUS405
Re: Bow design Theory or Looks? [Re: simonp] #186401
07/28/09 11:23 PM
07/28/09 11:23 PM
Joined: Feb 2009
Posts: 678
Palm Beach County
TheManShed Offline OP
addict
TheManShed  Offline OP
addict

Joined: Feb 2009
Posts: 678
Palm Beach County
The G-Cat 5.7 is great in the waves. I think that is why I kept it all these years. It was once given the Cadillac of Rides rating. There was a string about a boat to ride up on beach with. I went through 3 bottoms hitting the beach over the last 25+ years; each time I had to lay-up more glass on the fine V-Hull bottom, as the years of beaching would sand it away. When we (the boat and I) were younger Id land on the beach flying a hull.

It was easier to sail up the beach then to pull those dual knife-edges through the sand. I have never pitch poled the boat even when buried up to the center beam front tramp and all. Ive done a few cartwheels with it though.

Mike


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Bow design Theory or Looks? [Re: TheManShed] #186408
07/29/09 01:37 AM
07/29/09 01:37 AM
Joined: Jan 2004
Posts: 196
Arkansas, USA
C
CaptainKirt Offline
member
CaptainKirt  Offline
member
C

Joined: Jan 2004
Posts: 196
Arkansas, USA
Agree with the smooth ride on the G-cat 5.7 AND the "joy" of trying to pull that sucker up a fine sand beach! IMO the Nacra 5.0 and 5.7 also are pretty smooth (fine/deep hulls) but not as smooth as the G-cat. Heard Hans is back building boats??

Kirt


Kirt Simmons
Taipan, Flyer
Re: Bow design Theory or Looks? [Re: Don_Atchley] #186420
07/29/09 06:49 AM
07/29/09 06:49 AM
Joined: Apr 2003
Posts: 1,669
Melbourne, Australia
Tornado_ALIVE Offline
Pooh-Bah
Tornado_ALIVE  Offline
Pooh-Bah

Joined: Apr 2003
Posts: 1,669
Melbourne, Australia
Originally Posted by Don_Atchley
Sailing Math

Lots of spray = lots of energy wasted

Lots of energy wasted < Looking Cool

Therefore:

Looking Cool > lots of energy wasted

And so furthermore:

Lots of spray = Looking Cool, and cancels out any concern for energy wasted


Thank you sir, could not have said it any better myself grin

[Linked Image]

[Linked Image]


Re: Bow design Theory or Looks? [Re: TheManShed] #186421
07/29/09 06:53 AM
07/29/09 06:53 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
veteran
bvining  Offline
veteran

Joined: Oct 2002
Posts: 1,226
Atlanta
Mike,
The wave piercing bow is the end result of moving more volume down to the waterline while keeping surface area constant (or reducing it.) The Acat designs did this because once you've moved the volume down to the waterline you need to remove surface area or you will end up with a boat that is too heavy for the box rule. Other designs moved volume down to the waterline in an effort to reduce wetted surface area that generally results from loading up traditional multihull shapes. Traditional multihull shapes have always suffered from adding weight as the surface area increases quickly as compared to a traditional mononhull shape.

So the net effect of moving volume down to the waterline is a pear shape with the topsides being thinner than the waterline. Once you take this shape to the bow, your classic bow shape is upside down and becomes what is being referred to as a wave piercing bow. That description is a bit misleading because even though the bows may seem to pierce a wave, the rest of the boat doesnt actually pierce the wave and the boat if affected by the wave at some point in a way thats pretty much the same as a boat with regular bows. The designers were/are more concerned with the waterline shape/volume than the bows and the bows are really just the end result of moving the volume down to the waterline.

The side benefit (and I own a wave piercing Acat) is that you can submerge the bows and the boat wont pitchpole as easily. See the recent BMWO trimaran shots for illustration. Sailing around with submerged bows like BMWO probably isnt fast, but if this happens in a gust, or during a bear away its a nice feature to have the bows keep moving underwater with little or less drag than traditional flat top bows. The boat doesnt really pierce a wave, the wave affects the boat in basically the same way. Think about a H16 and how the bows slow dramatically when they are submerged, this is what the wave piercing bows resist/avoid.

The downside of a bow with a pointy topsides is that you lose a bunch of utility, you cant walk on it, you cant attach hardware to it easily, etc.

So when you ask the question, you really need to talk to the designer and see what he thinks, and look at how he has the volume in the ama's and what the whole picture looks like. Having ama's that dont pitchpole as easily is a good idea for a 20 ft tri and something that I would consider having.

Deciding on the bow shape should be done in concert with the rest of the hull shape and boat design and not as a separate design decision.

Bill

Re: Bow design Theory or Looks? [Re: bvining] #186422
07/29/09 07:20 AM
07/29/09 07:20 AM
Joined: Oct 2002
Posts: 1,226
Atlanta
bvining Offline
veteran
bvining  Offline
veteran

Joined: Oct 2002
Posts: 1,226
Atlanta
Nice work by the way.

Re: Bow design Theory or Looks? [Re: CaptainKirt] #186424
07/29/09 08:26 AM
07/29/09 08:26 AM

A
andrewscott
Unregistered
andrewscott
Unregistered
A



Originally Posted by CaptainKirt
Heard Hans is back building boats??

Yes, last year he built a 35' g-cat power boat... (its for sale)
He is now building a few F-16's for this years nationals.

He has been doing some pretty cool R&D last weekend too...

Re: Bow design Theory or Looks? [Re: TheManShed] #186425
07/29/09 08:29 AM
07/29/09 08:29 AM

A
andrewscott
Unregistered
andrewscott
Unregistered
A



Originally Posted by TheManShed
I have never pitch poled the boat even when buried up to the center beam front tramp and all. Ive done a few cartwheels with it though.


Thats amazing... I have seen several G-cats pitchpole... and i sail with a guy who says if you get his more than 3 or 4" above the decklid... over you go.

Re: Bow design Theory or Looks? [Re: TheManShed] #186426
07/29/09 08:29 AM
07/29/09 08:29 AM

A
andrewscott
Unregistered
andrewscott
Unregistered
A



Originally Posted by TheManShed
Wettest ride has to be a Supercat 20 I wear goggles and a snorkel


dont forget the flippers!

Re: Bow design Theory or Looks? [Re: ] #186430
07/29/09 08:53 AM
07/29/09 08:53 AM
Joined: Sep 2007
Posts: 531
Lake Murray SC
FasterDamnit Offline
addict
FasterDamnit  Offline
addict

Joined: Sep 2007
Posts: 531
Lake Murray SC
Originally Posted by andrewscott
Originally Posted by CaptainKirt
Heard Hans is back building boats??

Yes, last year he built a 35' g-cat power boat... (its for sale)
He is now building a few F-16's for this years nationals.

He has been doing some pretty cool R&D last weekend too...



Such as??


Race cheap, race faster, Damnit!

E-Scow
24' ULDB

18HT hulls plus Gcat 5.7 rig = 18GT!
Re: Bow design Theory or Looks? [Re: FasterDamnit] #186434
07/29/09 09:25 AM
07/29/09 09:25 AM

A
andrewscott
Unregistered
andrewscott
Unregistered
A



hydrodynamic flow controls

Re: Bow design Theory or Looks? [Re: ] #186454
07/29/09 11:41 AM
07/29/09 11:41 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
Carpal Tunnel
Rolf_Nilsen  Offline
Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
Originally Posted by andrewscott

He is now building a few F-16's for this years nationals.


Hope he gets them done and tested before the Global Challenge at Gulfport Yacht Club running from 9th till 14th November. Would be great to have a new design there.

Re: Bow design Theory or Looks? [Re: ] #186491
07/29/09 05:38 PM
07/29/09 05:38 PM
Joined: Feb 2009
Posts: 678
Palm Beach County
TheManShed Offline OP
addict
TheManShed  Offline OP
addict

Joined: Feb 2009
Posts: 678
Palm Beach County
Andrew maybe he was a small guy....;-) to pitch pole.

Last edited by TheManShed; 07/30/09 06:23 PM.

Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Bow design Theory or Looks? [Re: TheManShed] #186493
07/29/09 05:58 PM
07/29/09 05:58 PM
Joined: Feb 2009
Posts: 678
Palm Beach County
TheManShed Offline OP
addict
TheManShed  Offline OP
addict

Joined: Feb 2009
Posts: 678
Palm Beach County
I'm sticking with the original (modified) design for the TMS-20 we have a lot a re-design time and $$'s invested. I could change my mind if I get overwhelming evidence but it seems to be more of personal taste.

I have Marks A-Cat at the shed and looking at the design I see the lower and flat waterline carried forward to the bow.

I spoke to Hans some time ago and he was messing with the F16s but Im not sure he is following through with it. He is fish farming and doing very well. The power cat has been around for some time and first started as a sailboat I think he is messing with the power cat some on the side.

Few years back my buddy and I where flying air-borne off of short stacked 6-8 footers off of Smathers Beach in Key West during an annual spring break spring camp out. I went block to block as we launched. We ended up digging into the face of the wave in front of us instead of landing on the crest. Forty-five degree bow first clear up to front beam at about 15 knots. The boat, not us, the boat stopped and popped backwards, surfaced and took off again surfing the wave trying to pitch pole. Im standing on beam climbing up and back to cut the main sheet. Good thing the crew was hooked up but not out. I went flying like a rag doll body slammed him hard. Its nice to have a good crew!


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's

Re: Bow design Theory or Looks? [Re: TheManShed] #186505
07/29/09 10:02 PM
07/29/09 10:02 PM
Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
David Parker Offline
old hand
David Parker  Offline
old hand

Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
Quote
He is now building a few F-16's for this years nationals.
He has been doing some pretty cool R&D last weekend too...

I spoke to Hans some time ago and he was messing with the F16s but Im not sure he is following through with it.


It would probably be best to re-post this under its own thread but I'll start it here.

Like Andrew, I've seen Hans working out details on his new F16 project. Now he is quite vocal that he will be producing as many as 5 GCat F16s in time for the Global Challenge in November in Gulfport, FL. If you visit his www.g-catmultihulls.com website and go to News you will find that he is looking for TEST PILOTS for his new boats! Whether or not you think a boardless boat can compete with a Blade or Viper, here's a chance for Florida sailors to warm up on Hans' new ride and help him out with your opinions. Experienced only need apply.

GCat F16 press release

Re: Bow design Theory or Looks? [Re: David Parker] #186508
07/29/09 10:19 PM
07/29/09 10:19 PM
Joined: Jul 2004
Posts: 2,718
St Petersburg FL
Robi Offline
Carpal Tunnel
Robi  Offline
Carpal Tunnel

Joined: Jul 2004
Posts: 2,718
St Petersburg FL
I did not see an email to submit information for test skippering.

Ooops nevermind.

Last edited by Robi; 07/29/09 10:20 PM.
Re: Bow design Theory or Looks? [Re: Robi] #186509
07/29/09 10:28 PM
07/29/09 10:28 PM
Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
David Parker Offline
old hand
David Parker  Offline
old hand

Joined: Jun 2001
Posts: 890
Dunedin Causeway, FL
Robi, you'd be a good choice. You know the F16s, F18s, the local waters, and you need a chance to rebuild your karma with the GCat. Good or bad, Hans is staking his money on his design. Find some big air and rip it up!

Re: Bow design Theory or Looks? [Re: Robi] #186510
07/29/09 10:36 PM
07/29/09 10:36 PM
Joined: Sep 2007
Posts: 531
Lake Murray SC
FasterDamnit Offline
addict
FasterDamnit  Offline
addict

Joined: Sep 2007
Posts: 531
Lake Murray SC
Wow. Hans is making some some pretty big claims. If he can match current daggerboard F16's I would think that would be quite an accomplishment.

Not so sure about the lack of spray claim. The 5.7 on a reach in over 15 knots created a fire hose straight up the side of the hulls as you went over every wave. I was trapped out, wearing an old Douglas Gill dingy foulweather, one piece suit and the spray was hitting my ankles hard enough to soak me up the legs to my chest.


Race cheap, race faster, Damnit!

E-Scow
24' ULDB

18HT hulls plus Gcat 5.7 rig = 18GT!
Page 2 of 3 1 2 3

Moderated by  Damon Linkous 

Search

Who's Online Now
0 registered members (), 25 guests, and 231 spiders.
Key: Admin, Global Mod, Mod
Newest Members
bmcmurr3, sdm27, CanadaMetal, Jamil, Maistrello
8113 Registered Users
Top Posters(30 Days)
Forum Statistics
Forums26
Topics22,389
Posts267,027
Members8,113
Most Online1,650
Sep 10th, 2019
--Advertisement--
Powered by UBB.threads™ PHP Forum Software 7.7.1