View Full Version : Designing small (15'-16') power catamaran


08-04-2002, 03:56 PM
Hi,
this is my first post so please bare with me as my post is quite long winded...
First a little history how my desire to design and build a very specific design of boat came about. Having lived aboard and sailed a 42' boat for 7+ years and lived in a nautical community for 14 years, I have observed that a percentage of mariners are interested in commuting from point A to B only and not so interested in the recreational aspect of boating. Often it is only one or two persons wishing to commute. At times I too fall into this catagory. With this in mind, through time I developed a list of criteria I would desire in the 'perfect commuter vessel'. Of course nothing is perfect and involves trade offs and compromises. My list of criteria and order of priority for such a commuter vessel is as follows.
- Safety
- economy
- all season comfort
- designed to transport two people only
With safety in mind, the vessel must be designed for anticipated sea conditions, plus a margin of safety for those sea conditions one cannot run from.
With economy in mind and the vessel being designed for two people only, dictates that the vessel be as small and light as practical. Moorage costs can be a significant factor in the cost of operating a vessel in my part of the world and so I believe that a catamaran arrangement allows the greatest opportunities to balance the vessel on a short overal length and design the hulls without compromise or consideration for people accommodation
The design I have in mind would ideally be no greater than 16' in length, arranged in such a way that the hulls are joined by aluminum extrusions (I am aware of the enormous stresses of two hulls trying to work independently of each other, vector calculations will aid in determining appropriate sizing and arrangement of extrusions) and an enclosed separate cockpit mounted (suspended, cushioned?) on centre with passenger on cg and driver forward. Ideally very small displacement 4 sroke engines located inboard each hull, possibly all aluminum 3 cylinder 1000cc 58 hp automotive pontiac firefly engines? Direct drive surface piercing props? Inboard engines presenting balancing options allowing shorter overall vessel length. A 90 hp 4 stroke outboard is an alternative but with the drawbacks of having to increase hull length for balance and no hot water for cockpit heating.
Is anyone aware of a similar design vessel? Am I out in left field with the design I have in mind and missing something obvious? There are many planning runabout boats available of the same size and horsepower, but become quite heavy and inefficient when providing the all weather comfort I have in mind and almost without exception are designed to provide for the accomodation of more than 2 people and in my opinion less efficient than the vessel designed specifically for two people.
Any feedback would be greatly appreciated. Best regards
Richard

tspeer
08-04-2002, 08:18 PM
Take a look at:
http://www.sname.org/AM2002/papers/Paper1.pdf
http://www.sname.org/AM2002/papers/Paper11.pdf
http://www.uscg.mil/hq/msc/PRGuidance/h1-06.pdf
http://www.gidb.itu.edu.tr/staff/~insel/Publications/phd.htm
http://www.powermultihulls.com/magazine/articles/why-multihull.htm
http://www.hypermax.com/multihullsmag/magazine/articles/cat%20hulls/performance_of_cat%20hulls.htm


This paper might be relevant if you were to adapt it to narrower hulls if you were interested in semi-planing speeds, especially the bit about double chines:
http://www.sname.org/AM2002/papers/Paper4.pdf

View Full Version : Designing small (15'-16') power catamaran