San Carlos, Sonora, Mexico Forums Home 

San Carlos Mexico Forum
Welcome to our forum. In order to post in our forums you must be registered. Please take a minute to register to enjoy the full benefits of the forum. Registration is FREE and your information is kept private. When registering, please make sure your email address is entered correctly-if incorrect, you will not receive your validation message. Please do not use your email address as your user name for your own privacy and security. Gmail account users should check spam or trash folders for our validation message after initial registration. We also suggest you add host@sancarlosmexico.com to your white list.

This message board requires you to register in order to post new topics, reply to topics started by other users, start polls, or vote on polls. As a registered user, you can edit your own posts, upload photos and view our photo gallery, and send private messages to other members of the board. Registered users can keep track of the topics they are interested in, and receive e-mail notifications when someone posts to one of those topics. Registered users can choose a theme and setup a profile, to include hometown, email & web address and avatar if desired.
We do ask that you post in the appropriate forum-look over the subjects and topics of all forums including the mercado section before making your first post. Posts in the wrong forum or not related to San Carlos may be moved or deleted without notice.
Please take a moment and register to enjoy all the benefits of the forum.
Bienvenidos!

 Moderated by: bartmanaz
New Topic Reply Printer Friendly
Monohull vs. Catamaran  Rate Topic 
AuthorPost
 Posted: Fri Jul 15th, 2016 08:22 pm
  PM Quote Reply
1st Post
supex
Member
 

Joined: Sun Jun 8th, 2008
Location: Sierra Vista, Arizona USA
Posts: 107
Status: 
Offline
Mana: 
Hey guys.I was wondering what are advantages and disadvantages of monohull or coatamaran?Thanks.

Back To Top PM Quote Reply  

 Posted: Fri Jul 15th, 2016 11:55 pm
  PM Quote Reply
2nd Post
barato
Member


Joined: Fri Jan 4th, 2008
Location: Jemez Pueblo, New Mexico USA
Posts: 371
Status: 
Offline
Mana: 
here's a start for you:

A catamaran (/ˌkætəməˈræn/) (informally, a "cat") is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stabilized craft, deriving its stability from its wide beam, rather than from a ballasted keel as with a monohull sailboat. Being ballast-free and therefore lighter than a monohull, catamarans often have a shallower draft (draught) than comparably-sized monohulls. The two hulls combined also often have a smaller hydrodynamic resistance than comparable monohulls, requiring less propulsive power from either sails or motors. The catamaran's wider stance on the water can reduce both heeling and wave-induced motion, as compared with a monohull.

Performance characteristics[edit]

Catamarans have two distinct primary performance characteristics that distinguish them from displacement monohull vessels: lower resistance to passage through the water and greater stability (initial resistance to capsize). Choosing between a monohull and catamaran configuration includes considerations of carrying capacity, speed, and efficiency.

Resistance[edit]

At low to moderate speeds, a lightweight catamaran hull experiences resistance to passage through water that is approximately proportional to the square of its speed. A displacement monohull, by comparison experiences resistance that is at least the third power of its speed. This means that a catamaran would require four times the power in order to double its speed, whereas a monohull would require eight times the power to double its speed, starting at a slow speed.[17] For powered catamarans, this implies smaller power plants (although two are typically required). For sailing catamarans, low forward resistance[18] allows the sails to derive power from attached flow,[19] their most efficient mode—analogous to a wing—leading to the use of wingsails in racing craft.[20]

Stability[edit]

Catamarans rely primarily on form stability to resist heeling and capsize.[17] Comparison of heeling stability of a rectangular-cross section monohull of beam, B, compared with two catamaran hulls of width B/2, separated by a distance, 2×B, determines that the catamaran has an initial resistance to heeling that is seven times that of the monhull.[21] Compared with a monohull, a cruising catamaran sailboat has a high initial resistance to heeling and capsize.—a fifty-footer requires four times the force to initiate a capsize than an equivalent monohull.[22]

Tradeoffs[edit]

One measure of the trade-off between speed and carrying capacity is the displacement Froude number (FnV),[23] compared with calm water transportation efficiency.[24] FnV applies when the waterline length is too speed-dependent to be meaningful. It uses a reference length, the cubic root of the volumetric displacement of the hull, V, where u is the relative flow velocity between the sea and ship, and g is acceleration due to gravity:
F n V = u g V 1 / 3 {\displaystyle \mathrm {Fn_{V}} ={\frac {u}{\sqrt {gV^{1/3}}}}} {\displaystyle \mathrm {Fn_{V}} ={\frac {u}{\sqrt {gV^{1/3}}}}}
Calm water transportation efficiency of a vessel is proportional to the full-load displacement and the maximum calm-water speed, divided by the corresponding power required.[25]

Large merchant vessels have a FnV between one and zero, whereas higher-performance powered catamarans may approach 2.5—denoting a higher speed per unit volume for catamarans. Each type of vessel has a corresponding calm water transportation efficiency, with large transport ships being in the range of 100–1,000, compared with 11-14 for transport catamarans—denoting a higher efficiency per unit of payload for monohulls.[24]

https://en.wikipedia.org/wiki/Catamaran

Back To Top PM Quote Reply

 Posted: Tue Jul 26th, 2016 02:08 pm
  PM Quote Reply
3rd Post
RichD
Member
 

Joined: Wed Dec 7th, 2005
Location:  
Posts: 1753
Status: 
Offline
Mana: 
The only downside I see is finding a slip wide enough.

Back To Top PM Quote Reply  

 Posted: Tue Jul 26th, 2016 05:06 pm
  PM Quote Reply
4th Post
Hook
Member
 

Joined: Wed Oct 26th, 2005
Location: Mexico
Posts: 2647
Status: 
Offline
Mana: 
Power or sailing cat?

Back To Top PM Quote Reply

 Posted: Sat Jul 30th, 2016 10:02 pm
  PM Quote Reply
5th Post
Jimmy
Member


Joined: Fri Jan 20th, 2006
Location:  
Posts: 1146
Status: 
Offline
Mana: 
I had a 41' X 24' trimaran. I had to pay for 2 slips or find a end slip. but I could get into a shallower area of the marina. 

Last edited on Sat Jul 30th, 2016 10:03 pm by Jimmy

Back To Top PM Quote Reply  

Current time is 05:57 am  
San Carlos, Sonora, Mexico Forums > Topical Forums > San Carlos Sailing Forum > Monohull vs. Catamaran Top




UltraBB 1.172 Copyright © 2007-2014 Data 1 Systems