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What Makes a Maine Cat P-47?
Maine Cat has been building lightweight composite sailing catamarans for 14 years and has over 90 very happy owners who are getting more mature each year. We have worked very hard to keep our owners in the Maine Cat family and we would like to build them their next boat even if it does not have sails. The key is keeping them out on the water using their boats more because they love the way they move through the water without much fuss.
The new Maine Cat P-47 (yes, it started out as a P-38, then a P-45) will feature the same qualities as our successful sailing models; lightweight composite Core-Cell cored structural assemblies, no imbedded wood in the glass work, easy to maintain surfaces and finishes inside and out, and robust bullet-proof systems of the highest quality. Our hull forms are sea kindly and very easily driven. The P-47 will have "slippery" 13.5 to 1 length to beam ratio hulls at the waterline when fully loaded. We predict she will burn 4 gallons per hour cruising at 15 knots or just shy of 4 nautical miles on 1 gallon of diesel.
Our prototype hull has already been be powered by OSSA Powerlite diesel-electric propulsion technology including twin 25 kW DC generators and twin 35 hp electric drive motors during our first round of sea trials. Data on this trial is noted in our May 18th update. Round two will have twin Volvo 160 hp D-3 common-rail diesels to test our hull design at higher speeds and compare fuel consumption numbers at similar speeds. Extremely high fuel efficiency is our technical target, but we have not forgotten the comfort of the captain and especially the admiral.
The beauty of the catamaran platform is the abundance of space and with our 6’-6” head room you feel like you are on a much larger vessel. You gain complete privacy with our standard double cabin arrangement having separate sleeping quarters and heads in each hull. Maine Cat enjoys working directly with our clients to customize each boat to perfectly match our owner’s requirements. A walk-around master queen berth is the standard arrangement and our bridgedeck saloon features comfortable swiveling chairs and couch with a “Pullman” berth conversion.
The Maine Cat P-47 offers a more comfortable ride, 2’-7” draft, super fuel economy, protected propellers and rudders all built to the highest quality standards possible…why not come to Maine and experience this exciting new design out on the water.
Design Considerations for Catamaran Performance
Over the past 15 years of designing, building and sailing our successful line of 22’, 30’ and 41’ catamarans we have learned what works in the real world of offshore voyaging and what does not. The displacement power catamaran hull form is the safest and most comfortable way to go to sea, but just as with monohulls there are good designs and bad designs. Hull shape is critical for a successful high efficiency craft. What are the important criteria for the best cat?
From my experience, it is the balance of lightweight stiff composite construction, ample reserve buoyancy, high prismatic coefficient, excessive bridgedeck clearance, low center of gravity and extremely fine hull shapes with a minimum of wetted surface area. Sounds pretty easy ……… but I am not aware of any 40’+/-power cat presently being built in production that has addressed all these issues successfully. Most grossly exceed their weight predictions and end up with “chubby” 7 to 1 length to beam ratios to support the added weight of obsolete building techniques and poor or cheap choices for heavier than necessary equipment selections and building materials.
For comparison the Maine Cat P-47 has the following values: Weight dry (no fluids) out of the shop = 16,500 lbs. Full load displacement = 29,900 lbs. Prismatic Coefficient = .69 Bridgedeck clearance (full load) = 31 inches Center of Gravity (full load) = 2' - 7" Hull beam to length ratio = 13.35 to 1
Resin Infusion in all P-47 Components
Controlling the vessel’s weight is key to the success of any catamaran design since our hulls have a smaller waterplane than a similarly sized monohull form. Resin infusion enables our laminators to produce consistently high quality parts with the perfect ratio of resin to glass for maximum strength at the lightest weight possible. Every fiberglass component in the new Maine Cat P-47 is composite resin infused with vinylester resin.
This advanced laminating technology produces composite structures that are stronger, lighter and have superior mechanical properties to those built with conventional hand lay-up and dry-bagging core methods. With resin infusion all laminates and coring are laid dry in the mold and held in place with contact adhesive. The part is then covered with plastic sheeting, the entire perimeter sealed and vacuum manifolds evacuate all the air and de-bulk the laminate stack. Catalyzed resin is then allowed to flow through numerous feed tubes until the entire stack is saturated and excess resin removed. Our 1” thick infused bulkhead panels weigh less than 1.7 pounds per square foot and are stronger than a conventionally laid part that is 30% heavier. In addition, infused laminates have no voids and are more resistant to moisture migration.
Our choice of coring has always been Core-Cell, the premium closed cell structural core in the world. Core-Cell is a SAN based plastic that forms a chemical bond with the infused vinylester resin. Our supplier cuts the P-47 core kits on a CNC machine to perfectly match the shape of our molds with the required panels of various densities and configurations. High density Core-Cell is used in all high stress areas in the Maine Cat P-47.
Lightweight boats are faster, more fuel-efficient and have a better payload carrying capacity than heavier boats. Additionally we gain a huge bonus in the air quality inside our shop since the vapors from the vinyl ester resin are sealed within the vacuum bag. Better for the environment and better for our crew.
Propulsion System
We look forward to working with customers to build them a Maine Cat P-47 that is powered with the size and type of equipment they require to meet their objectives. We look forward to our second round of sea trials in June and reporting the performance data we obtain with these new engines.
Stay tuned to our website for regular updates. Check out the video of our prototype. Darn, even I was impressed with the results.
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