Sunday, August 15, 2010

James Wharram Catamaran less or more than a Tiki 38

   We built our first Wharram catamaran, a Tiki 30 2 years ago. We have a blog bout the construction and sailing of that boat at .  We have sailed this boat several thousand miles since launching and spent many weeks on board  in the Bahamas, the Keys and the west coast of Florida. We have also exhibited her at several boat shows and had a received a lot of feedback.
   The boat sails very well in most conditions and is very comfortable most of the time. But there are a few features or lack thereof which could be improved upon. Several people who have spent time on this boat and have many years of experience on a variety of sailboats  sat with me several times and we discussed the issues and went through several versions before we decided that we had made some significant progress.
   First we added 6" to the aft end of the boat. It seems like most if not all Tiki 30s trim down in the stern.The bows tend to be very empty and light. We added a fourth beam 5' behind the  beam right behind the house.We lengthened the houses by 1' for more space in the galley and nav area.
  We also raised the sheer height by 1'. This is to increase the bridge deck clearance to 3'. Sometimes when our Tiki 30 is jamming along at speed in seas we would thump pretty hard. This really slowed us down when going to weather.Raising the sheer also provides us with wider main bunks and makes the fwd bunk spaces much more comfortable. It also allows us to achieve standing headroom in the galley and the nav area.
  We used the space in the starboard hull between  the 3rd and 4th beam to have a separate head compartment. By building a small house to the height of the top of the beams we  are able to get decent sitting headroom over the toilet and you can stand in the companionway to the head.
  In the same space to port we have include a storage compartment for the propane bottles as well as a large space to store foulies and wet suits. Also we have included a shower that can be used in the companionway or on deck.
   Behind the main cockpit we have put in a helm station. tiller steering or wheel steering are can be accommodated. The helm station  has a fwd windscreen and roll down side curtains for helm protection in cold and/or wet weather.
    We have included two twenty HP outboards in this design for stellar motoring speeds and great maneuverability.  These motors are power tilt and are located under the seats in the main cockpit area. Being in the center of the boat will minimize cavitation and increase maneuverability. Batteries and fuel tanks are also stored under cockpit seats. There are also built in ice chests in the cockpit
   We have included two 160 watt solar panels atop the bimini and 4 8d batteries for increased electrical generation and capacity. This is to allow for the use of either an ice maker or an electric reefer unit.
  I like to sail and I especially like to sail fast. To facilitate this we have used a 42' aluminum mast with a big roach full battened  square top main  with a mast head rig. To help even more with light air performance we have added a retractable carbon bowsprit on which we can fly a srceecher or asymmetrical spinnaker. Working sail area is 650 sqft. It's ok to reef when needed.
   The beam has been increased to 19'8". The weight will come in between 4500 and 5000 lbs. The idea here is to build a bigger faster boat than the Tiki 30, while keeping the small boat feel and performance. The Tiki 38 is a much larger, heavier boat and does not have the same good sailing ability as the Tiki 30.
   Here are some drawings of this design. Any thoughts or comments are welcome.