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.
- Cal's Evals
- KD 920 Offshore Catamaran
The KD 920 is a stretched version of the Kohler KD 860, one of a family of novel multihulls designed by Bernd Kohler. It is a wide boat with trapezoidal (flat bottom) hull shape and incorporates anti-vortex panels in place of keels, daggerboards or centerboards. The stretch is a two foot (610mm) plug at the maximum beam point (4893mm from the bow), providing hull space for an enclosed shower, and additional salon space. It increases displacement by 0.38 ton, over 80% of which is additional payload. The intent is to build it using Kelsall KSS foam-cored glass/epoxy panels rather than glassed plywood of the basic design.
The following figures show this boat in comparison with the average values of 58 other catamarans with waterline length between 29 and 31 feet, listed on the Multihull Dynamics, Inc. website.
- 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
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- 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
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- 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
- Schionning 1100M - Miaow
After joining me for trailer lunch today (I am working at home this week), M took me over to the boatyard to tour a Schionning catamaran thats just two metres bigger than ours is going to be. - Schionning 1230 Bi-Rig Mahna Mahna
The journey of Mahna Mahna started the moment we decided we wanted to build our own Catamaran and then sail the world on her, but the actual building started in September 2005. The initial materials for our Schionning 1230 Wilderness Catamaran arrived from ATL composites and some other suppliers, over August 2005 and work on the strongback, the frame upon which the hulls are built, started in September.
- Pat's Dock
- How I chose to build the KD 860/920
This is my first boatbuilding experience. Here are the boat characteristics I desired that led me to the KD 860/920 build.
- 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
- Analysis and Comparison of Cruising Multihulls 2008
Article Presentation
This is the full and complete presentation of article "Analysis and Comparison of Cruising Multihulls 2008". This article describes "First Order" multihull design analysis. It is the description of the analysis and comparison methods of multihulls on this website.
