Saturday 28 June 2014

Cruising Fulmar - More design mods

A few pics to update some modest progress on my design mods for the Cruising Fulmar. For the benefit of those not reading earlier posts, this is to be an 18ft lapstrake cruising cutter based on Iain Oughtred's original design for the Fulmar and with inspiration and modified plans drawn by Kees Prins.  The extra work I am doing is to get more cabin space, have twin rudders stick driven and insert a well  for the outboard.

Re the cabin space, I have decided to push the centreboard aft so that the front of the case sits under the bridge deck and have a dagger board just ahead of the mast step to give lateral resistance matching the sailplan. This means no centreboard case in the main cabin space.  You can hopefully get the idea of this with yhe model pics below with white cardboard in the model representing the centreboard case and forward dagger board case.

Centreboard will sit just under cockpit floor. The two brass tubes drive the twin rudders and will sit just above the cockpit floor.  The centreboard will swing down and not be as wide as standard design but total lateral resistance will also come from the forward dagger board as well as more effective size of rudders area compared to one rudder. The combination of swing centreboard and forward dagger board will allow flexible options to trim balance and set rigs with the three sails of the cutter rig.

...and here you can see the forward dagger board case represented by the white cardboard and teh extra space created in teh main cabin area - bunk soace either side and feet space projecting back under cockpit seats. The square frame (which will be stainless steel)  is mast step support - mast will be in tabernacle on cabin top.  This frame give some central space for (optionally) a seat, a kitchen box/cock top, or a porta poti. 

And now for the cabin. I am experimenting with a stitch and glue structuring of the cabin top. The pics below shows the "chine lines" on which this cabin top will be put together.  I'm in the process of spiling the patterns for the "planks" which make up this cabin top.  The strata in this mock up will not be part of the structure - it's just there to show the lines.  More to come once I have had a go at making the stitch and glue model.