[Public-List] Mast Rake

[crufone at comcast.net]

Hi Jeff, 

I too am used to smaller boats with adjustable mast rake.  The general consensus among the Alberg 30 family is that the designer expected the rig to be set up plumb. If you examine the mast step, a raised hub over which the soda straw, (the mast) rests there is not much allowance for mast rake adjustment. 

Several years ago I helped Dan Walker set up his boat and tune the rig after an extensive on-the-hard refurbishing. I used an average of the rig tensions which I have gathered from participants on the Public List and our Web site. For the mast rake I attempted to achieve about a foot of rake when measured at the coach roof. If I remember correctly I was not able to achieve this because most of the mast pressure was on the aft 1/3 of the circumference of the mast extrusion on the mast step. I felt that this was not good. So I backed off the rake until there was about half the rake. This meant that the very forward bottom edge of the mast extrusion was approximately 1/16 inch above the mast step and approximately two inches aft of the forward edge..... extending to the aft edge.... the bottom edge of the mast was tight against the step.  To measure the relative rake I used a line hoisted fully on the main sail halyard weighted like a plumb bob and measured just above the coach roof to the aft face of the mast. 

Dan and I went sailing on her shake-down in about 12 to 15 knots of wind and five foot seas.  I can't compare her pointing ability in reference to other boats because we were the only ones out there. Her helm was OK .....neutral to just a tad of weather helm. Could not have been much weather helm because the wooden part of the tiller split at the rudder head fitting, due to age not helm, and we were able to sail while Dan went below and got some c-clamps to hold all together.  We sailed the remainder of the shake-down using the c-clamps. 

I suggested to Dan that rig set up is going to be a trial and error, adjust and test type of exercise until you achieve the feel, helm and pointing ability which you desire.  It is my contention that while most or perhaps all boats came from the same mould that all boats will be slightly different. 

Perhaps Dan can chime in here to tell us if he has tweaked the original rig set up for the shake- down that day or has just left it the same and if she developed helm in different wind conditions. Another major adjustment available is that the mast step plate can be shifted fore and aft.  From what I have heard most owners on-list shift this plate to max forward position. Again, the guys at Whitby probably drilled the holes for these plates in slightly different places on different boats. I don't know if a fixture was used to locate the plate prior to drilling the mounting holes, or if the guys just thought well this looks good and drilled the holes. I'll bet that if you were to measure the distance on several boats from the stem head fitting to the fore edge of the mast plate you might find a difference of an inch or so. That coupled with the two inches? or so of designed adjustment will provide your boat with a range of handling characteristics.  Again it would be worth the effort to set up your rig via an adjust and test sail exercise to determine the best location of the mast step for your particular boat.  In theory there is only one optimum position and rake for the feel, helm and pointing ability that you desire. I endeavour to set up a boat somewhere between good pointing ability and a balanced helm. I am certain that others will contribute to this thread. 

Michael #133 



----- Original Message -----




From: "Jeffrey" <fongemie at gmail.com> 
To: "Alberg 30 Public List -- open to all" <public-list at lists.alberg30.org> 
Sent: Friday, June 24, 2011 2:57:22 PM 
Subject: [Public-List] Mast Rake 

Hi Everyone, 

I was wondering about Mast rake on our boats. I've had a couple of 
smaller boats and adding a bit of mast rake really helped point closer 
to the wind. I have a hobie cat that has lots of mast rake, and a ton 
of weather-helm...points good though. 

In searching the archives I came a cross a couple of posts where it 
was decided that the mast is best left in column.  I'm wondering why? 
Anyone add some rake and like it??  I love the idea of pointing 
higher, however I don't want to deal with much weather helm. We are 
just cruisers. 

-Jeff 

-- 
Jeffrey Fongemie 
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