Changing Mast Rake

I am the new owner of a Cascade 29' (1979 hull, splashed in 1985). The standing rigging appears to be original and have some "challenges".

The mast has no detectable rake (I hung a weight from the mainsail halyard sheave and measured aft along the boom).

As the boat is new to me, I don't have much experience sailing her under different conditions to decide if I want to alter the rake to provide more/less weather helm. So that leaves me with two questions:

  1. How much rake should I build in?
  2. Is there a simple formula for altering stay lengths to achieve a specific rake [like SIN(change in rake) ~ (change in forestay)/(mast height) or something]

There are several cracked swages and I don't feel comfortable risking the rig by going out for extended dorking around under sail to determine how she feels currently. Also, with the current rig, the mast is not plumb starboard/port by about 1.5" and the "long side" backstay turnbuckle is double-blocked. So there's that.

 

SloopJonB

Super Anarchist
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You're going to need a rigger to make the new rigging so consult with them beforehand.

No way you can preordain if you need to change the mast rake - you'll have to sail it and see what the helm feels like.

 

PaulK

Super Anarchist
Measuring rake with a plumb-bob will only work when the boat is floating level on her waterline. If you are on board a 29' boat, chances are that your weight - wherever it is - is keeping the boat from floating level.   Plus, if you're on board the boat,  how do you see the waterline to make sure you're level anyway?   If the boat is on a trailer, the same thing applies. Where would you place a carpenter's level to determine that the boat is level? Everything is curved or cambered or tilted. Get the standing rigging fixed and go sailing.  Then you'll know whether you need to adjust the rake. 

 

neuronz

Anarchist
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europe
Order your new standing rigging with a turnbuckle in the headstay. The additional cost will be negligible and you will be able to finetune your rake.

 

Bruno

Super Anarchist
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136
You can go sailing with some temp stays rigged just in case but you have to sail, as noted, to know how the helm balance is.

 
Okay, so here's my take away...

You cannot tell how much rake to build in without sailing it. So have new stays built with some random measurements and then sail it and get some new stays built.

That sounds like a recipe for about doubling my re-rigging costs.

Most things I've ready say somewhere in the 1-2 degree range. I guess if I have to start somewhere I'll start there.

 

SloopJonB

Super Anarchist
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Great Wet North
Wrong.

You cannot tell how much rake to build in without sailing it. So have new stays built with enough adjustability to enable the rake to be dialed in.

It's the way most boats are rigged.

 
Larry Knight said:
The boat is a cruiser so we are talking about developing a soft helm so you or self steering gear don't work too hard.  As said above, if in doubt get the new rigging built with adjustable ends and play with it.  Avoid raking (edit) on just what it looks like.

For a cruiser, I would want it more forward (rather than too far back) without inducing lee helm.   It assists to keep the bow down to windward (not rounding up) and works better downwind.  Depending on the boat, raking to much can also cause issues with low booms.
@Larry Knight That's actually SUPER helpful. So much of the info out there on rig tuning is for racing boats. I hadn't really thought about the effects on my windvane and autohelm. Also, the boom is already pretty low (due to a hard dodger that's super useful here in the Pacific Northwest).

Your reply came just in time too; my new roller furler is supposed to be delivered today and I need to make up the new headstay!

 

Carrera

Member
404
37
Detroit, MI
The other thing to keep in mind is that most rigging can be shortened after it is made too so a rigger can error on the longer side, even with adjust-ability, and then shorten from there if you are unsure

 




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