According to the Russ McDonald 5.2 tuning guide mast rake should be " center to REAR OFF HATCH". Could someone explain to me what that means? I just purchased a Nacra 5.2 and have replaced all the rigging. Now I need to adjust the rake.

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2016 Hobie Getaway
1978 Nacra 5.2
1978 Hobie 16 (back in the day)
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I have no idea what that means but I sail a N5.2 among others and think my mast is purity much 90deg to the hulls
That said I refer to those that know the technical meaning of the wording you mentioned

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Jeff O
N5.0
solcat 18(sold),
N5.2,
H16
Camarillo CA
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Usually when a tuning guide gives you a setting like you described you get the boat level and take a trap wire forward to the point that the rear of the bridle tang meets the hull. You might have to add a bit of line to the trap handle to reach this point. Pinch the trap wire at the point that it hits the hull by the tang and then walk back until the point that you are pinching touches the rear of the hull. It should in your case be between the center and rear of the hatch. I have also seen where you tie a weight to the halyard and use it like a plumb bob but on the 5.2 it appears that the front ports are quite forward and that would give little mast rake. Curious to hear others answers.


Pete

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Pete Knapp
Schodack landing,NY
Goodall Viper,AHPC Viper,Nacra I20
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Quote

center to REAR OFF HATCH

when we measure rake on our cats - we typically use a trap wire to gauge. depending on your trap setup

we take the skippers trap wire and walk it forward and stretch it taught, touch the deck or beam the most forward part of your boat with it that you can (may need an extra short piece of line) - and note it's location. Then we walk it aft and do the same This is typically somewhere's on the rear port (on a mystere). Either front, center of aft on the hatch.

This is just a starting point to know where your mast is currently (doesn't not indicate and actual rake degree) and now you can rake forward or aft and have a measurement / knowledge of where you started / ended .,... and this can be compared to other boats (of the same make), or just as a reference for yourself and your setup.

Now if you haven't changed anything else - you can probably just make adjustments to your shroud pins and have the same basic understanding "more or less rake applied" but if you change things like shroud lenght or side stay adjuster... this changes the variables a little and using this method will let you know how much your rake has changed



Edited by MN3 on Mar 23, 2017 - 09:29 AM.

Understanding what the position of your mast is just the starting point. Knowing that changing the rake fore or aft effects the feel on the rudder and how the boat behaves. When you have the rake right for the normal wind conditions you are sailing in, the helm should have just a slight bit of weather feel to it, meaning it wants to round up. Too much weather helm slows the boat down because you are fighting it and bad things start to happen when you have lee helm (the mast is too far forward). In a perfectly dialed in boat the helm will be very nearly balanced, but I think most of us err towards the weather side of things. Then you throw in varying wind conditions and what once was set up perfectly now sucks.

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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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