Port of MDI
- Articles
- Six Kinds of Cats and Two Kinds of Tris
By Calvin H. Markwood
"Six Kinds of Cats and Two Kinds of Tris" documents the use of the same analytical methodology to compare the designs of six prominent catamaran designers.
- Analysis and Comparison of Cruising Multihulls 2008
By Calvin H. Markwood
"Analysis and Comparisons of Cruising Multihulls 2008" is the application of some traditional and unique mathematical methods of evaluating and comparing modern cruising and racing catamaran and trimaran sailboats."
- Cal's Evals
- DEAN 441
This catamaran is a conservative cruising sailboat. The specification, performance and stability figures for comparison come from the averages of 31 cruising catamarans in the 42-44 foot waterline length. These boats are featured in the Multihull Dynamics, Inc. website. The analysis elements, followed in brackets by the average values, are:
- SPIRITED 380 MKII
This attractive, high-performance cruising catamaran isavailable through Stallion Marine for the do-it-yourself amateur builders, it was designer/builder Craig Schionning. The components are molded and precision cut, then shipped as kits for assembly at the builders site. Details on the design, assembly method and performance can be found on the Stallion Marine website. The Multihull Dynamics, Inc. (MDI) evaluation of the boat in comparison with the averages [shown in brackets] of 50 cruising catamarans with waterline lengths of 36-38 feet follows:
- St Francis 44 MKII
This 44 foot cruising catamaran is a bit of a puzzle to analyze because she has a significant bow overhang, unlike most of her sister ships. Thus, it is hard to know whether to compare her with other catamarans in the 44 foot overall length range or 39 foot waterline range. When faced with that, it is always interesting to do both. So in the data to follow, the first value is for the SF44, the second [in brackets] is the average of 34 boats with overall length between 44 and 45 feet and the third is the average of 50 boats with 39-40 foot waterline length.
- GEMINI 105Mc
The Gemini 105MC is the latest in a family of Gemini catamaran sail boats in the lower-30 foot length range. It is characterized by relatively narrow beam, full length bridgedeck and significant popularity. The following information from the Multihull Dynamics, Inc. website database shows how this 31.75 foot waterline length boat compares with 49 other cruising catamarans with waterline lengths from 31 to 32.5 feet. Averages and ranges for the comparison boats are in brackets.
- Comparative Trend-Line Analysis
- SHUTTLE CAT 31 Trend-Line Analysis
This is MDI's Comparative Trend-Line Analysis of the Shuttle Cat 31. In the Trend-Line Analysis the Shuttle Cat 31 is compared to the MDI's Bridgedeck Clearance evaluation standards developed by Cal Markwood (when Bridgedeck data is available), along with this, the Shuttle Cat is also graphed against the Catamaran Database Trend Lines of performance and stability results of the 658 Catamarans. The specific Catamaran Database Trend Lines used for the Comparative Multihull Analysis are: Bruce Number (BN), Sail Area to Displacement ratio (SA/D), Base Speed (BSpd), Texel Rating (TR) and Stability Speed (SSpd) and Cal Markwood's Stability Index (SI-CM). This analysis comes complete with 18 specifications, 10 are unique performance and stability evaluations, a profile and layout drawing are also included.
"The Shuttle Cat 31 is a fast cruising catamaran that is very similar to another Shuttleworth production cat, the Tektron 35. She represents one of many design's from Shuttleworth's Spectrum 42. The unusual yet well proven flared hull form creates a small waterline imprint for speed, and a wider form above the waterline for increased interior accommodations and additional buoyancy when reaching. Sailor's Multihull Guide, 1st Ed., 1998
This Trend-Line Analysis may be purchased separately : Buy Analysis
__________________________________________________________
- Featured Catamaran
- MANTA 42 MkII - Custom Multihull Eval
This MDI Custom Multihull Review features the MANTA 42 MK II. For catamarans this involves Bridgedeck Clearance evaluation (when Data Available), Performance and Stability results. Along with this we have graphed the MANTA 42MK II against the Database Trend lines of all Catamarans in the MDI Database. These Database Trend lines are: Sail Area to Displacement ratio (SA/D), Base Speed (BSpd), Texel Rating (TR), Stability Speed (SSpd) and Cal Markwood's Stability Index (SI-CM).
Cal Markwood, Engineering Analyst, has written a "Cal's Eval" which narrows the comparisons further by evaluating this boat against other boats in the MDI database that have similar specifications.
This analysis comes complete with 18 specifications, 10 are performance and stability evaluations, a profile and layout drawing are also included.
This type of evaluation allows the potential buyer the ability to see how this vessel compares to all vessels of that Type as well as vessels with similar specifications.*
This Custom Multihull Evaluation may be purchased separately : Buy Evaluation
__________________________________________________________
- Featured Trimaran
- DRAGONFLY 1000 Offshore Cruiser CME
MDI'S featured Trimaran is theDRAGONFLY 1000 Offshore Cruiser with a complete MDI Custom Multihull Eval. For Trimarans this involves Performance and Stability results. We have graphed theDRAGONFLY1000againstthe Database Trend lines of the allTrimarans in our Database. These Trend lines are: Sail Area to Displacement ratio (SA/D), Base Speed (BSpd), Texel Rating (TR) and Stability Speed (SSpd).Cal Markwood, Engineering Analyst, has written a "Cal's Eval" in whichhe compares this vessel to other vessels in the MDI database of similar specifications.
This type of evaluation allows the potential buyer the ability to see how this vessel compares to all vessels of that Type as well as vessels with similar specifications.*
This Custom Multihull Evaluation may be purchased separately : Buy Evaluation
- Multihull Construction - DIY Owners
- FUSION 40
A little fit and a lot of Cruising!
- Pat's Dock
- Step 2: KSS build of a KD 920
Derek Kelsall and Bernd Kohler are collaborating for a build of a modified KD 860 using the KSS building technique. For more details read on.
- Press Releases
- MDI Presentation - Analysis & Comparison of Cruising Multihulls
Many people in the process of buying cruising multihulls are frustrated when attempting to sort fact from fiction. This workshop presentation teaches you how to use, evaluate and intrepret multihull comparison results. - Derek Kelsall - USA Gulf Coast Florida - KSS Workshop
KSSWorkshop - Gulf Coast of Florida
PENSACOLA KSS WORKSHOP 2008
DATES
Thursday through to Sunday September11th to 14th, 2008.
LOCATION
Close to Pensacola in Milton, FL.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- Sailing
- PASSAGE STRATEGY - By Dave Abbott
I asked Dave Abbott how he planned long range passages - here is his answer:
Many people don't have a clear idea in their mind about how they are going to make a passage - they lack a strategy - and that contributes to a sense of anxiety when they sail offshore.
- Technical
- Explanation of Abbreviations
Explanation of Abbreviations used in Multihull Data, Multihull Comparisons and Custom Evaluations
