[Rhodes22-list] Fw: Bob Weber's Analysis Of Lee Helm

Roger Pihlaja cen09402 at centurytel.net
Fri Sep 17 10:56:22 EDT 2004


Mary Lou,

One thing I forgot to mention in my previous post.  In order for Bob's push/glide test to work properly, your hull must be absolutely level on the waterline from side-to-side.  If the hull is heeling to one side or the other in the push/glide test; then, there will be an asymmetry in the underwater shape that will cause the glide to consistently veer in one direction.  This consistent veering will occur even in the absence of any problems with shoal draft keel shape &/or alignment and could lead to a false positive in the test.

Note that if you do get a positive result in the push/glide test; then, you can also test to see how many degrees of heel are required to cancel out the veering effect.  You could do this by shifting ballast around to set the degrees of heel to whatever was required & then repeating the push/glide test.

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message ----- 
From: Roger Pihlaja 
To: The Rhodes 22 mail list 
Sent: Friday, September 17, 2004 9:35 AM
Subject: Bob Weber's Analysis Of Lee Helm


Bob,

Given the way the hull & shoal draft keel are molded together in one piece, it's hard to understand how the shoal draft keel could be misaligned or misshaped.  However, your suggested diagnostic test involving pushing the boat & noting a definite tendancy to veer one direction or the other during the glide seems quite definitive.  Plus, it has the advantage of being simple & quick.  If there is something crooked down there, your push/glide test will point it out.  If your push/glide test shows no definite tendency to favor one direction over the other; then, all the hypothesis regarding hull & keel shape &/or misalignment can be put to rest.  I wonder if the GBI factory has something akin to a "Go/No Go" gauge for shoal draft keel shape & alignment?

Roger Pihlaja
S/V Dynamic Equilibrium 


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