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post #509 of Old 03-11-2018
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Re: Multihull Popularity and Interesting Designs

Though the graphics really suck in this article they are really informative and get at what makes a cat "good or bad" for cruising...

This page was put together from interviews with builders, designers, delivery captains, owners, charterers and from our own personal experiences delivering boats up and down the East Coast, offshore and vacations aboard with both experienced and inexperienced catamaran sailors. It’s both practical and technical. The information is not intended to support any particular product, though we obviously have chosen Fountaine Pajot because we believe it is a good example of our discoveries. Many people get referred to this page by other dealers and owners.
This paper is designed to highlight the 4 important distinctions that will help you understand the builders’ intent. Is he offering an inshore or offshore Cat? The 4 important criteria to consider (aside from overall quality and integrity) are:

Stability. Beam to Length ratio and Static Stability
Pitching. The comfort factor
Bridge Deck Clearance
The Control Cockpit. Flybridge or deck-level?
Load Carrying Capacity
What is Wrong With This Picture?

What’s missing is the bridge deck clearance! The single, most important factor is the load carrying capability! This affects everything else. Find out more below…

Virtually all of the experienced builders, especially the European builders who must sail their boats transatlantic to their bases in the Caribbean, have settled on a minimum length to beam ratio (L/B) of approximately 50%. That’s a 20′ beam on a 40′ boat. As the boat gets larger, over 50′ or so, you can back off from this ratio a bit and still have adequate stability. These same experienced builders put enough beam into the individual hulls to give more than adequate load carrying ability. One sign of an older design (often resurrected these days and promoted as new) is narrow individual hulls, sometimes supplanted by (needed) extra beam because the hulls no longer have the required buoyancy.

(By the way, you can often recognize these designs from inside because the berths will be high and spanning the bridge deck‐‐the hulls don’t have enough volume to carry 4 full size double berths! Watch out!)
Lots to digest in this one...and I smell some typical BS here and there. But one of the more extensive I've seen.

Last edited by smackdaddy; 03-11-2018 at 03:59 PM.
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