SV Pilgrim - 1979 Morgan 382 - Homeport: Beaufort, NC

Thursday, January 1, 2015

Creating A Template for Morgan 382 Rudder Modifications

Happy New Year everyone! 

I realize the last few posts have discussed our ice box rebuild project, but it’s time to change tack.  Yes the ice box project is still on going, but it is nice to have an outside project for the occasional eastern North Carolina warm, sunny winter day.

As the Morgan 382 design evolved into the 383 and again into the 384 modifications were made to improve upon the original design.  During the evolution the design received a taller rig and a larger rudder.

When a previous owner replaced Pilgrim’s mast in 2002 she received a taller rig that matched the later Morgan designs.  Her rudder remains original… until now.
Pilgrim's original rudder. 

My understanding of the primary issue is that when the rudder is turned water flows over the top. This flow creates an eddy / low pressure area on the upper, aft side of the rudder.  The eddy reduces the efficiency of the rudder.  By filling opening between the hull and the top of the rudder this detrimental effect is eliminated.

Using strips 1/8” Luan plywood (I’ve seen this product spelled many ways including Lewon and Launan), duct tape, and hot glue I created a template for the rudder addition.
Creating a template for the rudder addition.

NOTE: When creating the template it is very important rotate the rudder through its arc to ensure the addition does not contact the hull.
Template with rudder centered along hull.

Template with rudder rotated hard to starboard.

Once pleased with the shape and fit, I transferred the template to a single piece of luan plywood.
Transferring the initial template to a single piece of plywood.

The single piece template is much more durable.  This shape represents the minimum increase to the size of Pilgrim’s rudder.
Template in place along Pilgrim's rudder.

Here is an image I found on the web of what I believe to be the later model stock Morgan 383 rudder.
Image of stock Morgan 383 rudder.

The later 383 rudder appears to carry aft as far as the boot strip paint. 
Below is a digital mock-up of what I believe would need to be added to Pilgrim’s rudder to match the later Morgan design.
Red area represents additional increase in Pilgrim's template to match stock 383 rudder.

I would rather not go too big in my modifications.   If anyone reading this has insights to offer please share.

1 comment:

  1. It is important to maintain the proper clearance. The later model rudder has more than your template. The designers had to consider flexing of the hull and resulting distortion in heavy weather If you are too close it could lock up or become damaged.