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Hunter 37 cutter Mast Rake and Prebend

Oct 25, 2011
30
Hunter 37 Cutter Yankton SD
Hunter 37 cutter owners, how much prebend and rake do you run....Yes its a very stiff mast :)

Got an older mainsail, looks very full, but mast is straight, and no prebend, the mast is all the way forward at the collar, so planning on raking back, then inducing some prebend with lower forwards.

PS- the new foam reefing genoa 130 was the perfect size to replace the cutter setup on this boat. It sailed very well set-up this way.

Paul Bommersbach
Yankton SD
 
May 31, 2007
716
Hunter 37 cutter Blind River
Did you convert to a sloop rig?
These sticks are designed to be kept straight with no prebend. Rather than using prebend to flatten your rather full mainsail, I would rather see you get the sail recut. Result should be better performance and less rig stress.
 
Nov 8, 2007
1,286
Hunter 27_75-84 Sandusky Harbor Marina, Ohio
Rake should be around .75 to 1.5 degrees or 7 to 14 inches at the boom on your boat. Because winds are higher farther off the water winds actually blow down from horizontal at this angle. Raking the mast keeps the main perpendicular to the wind.

Actually this is just a starting point, since rake controls weather helm. Raking the main moves the center of effort of the sails aft, increasing weather helm. You want a little weather helm, but not so much that you need excess rudder (dragging) to hold the boat on a strong wind.
 
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Jun 8, 2004
887
C&C Frigate 36 St. Margaret's Bay, Nova Scoti
You will find that the fixed mast step and the tight fit at the partners will limit the amount of rake you can induce. It might be possible to get a bit more rake by using wedges instead of the hard rubber spacer at the partners, but as Sandpiper states, this spar is really meant to stand straight. That leaves forestay/backstay and shroud tension to determine where the masthead ends up... and the range of adjustment is not large, given the stiffness of the mast section. I start tuning with a straight mast, adding backstay tension to prevent sag on the furler luff. The cap shrouds are tensioned to keep the masthead from falling off to leaward when sailing and then the forward lowers are adjusted first to keep the mast in-column followed by the aft lowers, which are tensioned a tiny bit less. This should result in a spar that appears vertical or very slight raked aft (depending on your boat's fore & aft trim) with a tiny amount of pre-bend. I don't own a Loos gauge, so I do it by feel and probably tend to err on the slack side of tension. When sailing close hauled in 10 - 15 kt, my lee shrouds are a bit slack but not flopping around.
 
Sep 29, 2016
35
Hunter 37C Havelock
You can download the owner's manual from this site. The answer you seek is in there straight from the manufacturer. It is 1 inch of prebend. It doesn't address rake specifically but you can decide where you want rake based off of weatherhelm.
 
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Blaise

.
Jan 22, 2008
358
Hunter 37-cutter Bradenton
Midnight Sun's mast is as vertical as can be measured. With a 135% up and 18 kts of wind the helm has very slight weather helm. It is more difficult to measure the center of effort in a sail plan when you have multiple headsails. The other factor is center of lateral resistance. The hunter 37 cutters have two vastly different keels. The deep draft, while being a little over a foot deeper, is also about 2 1/2 feet shorter than the shoal draft keel. By the way, the rudders which also contribute to lateral resistance which affects weather helm, are the same, which is why so many shoal draft boats also have bent rudder shafts. I have a backstay adjuster and will load the backstay to about 7000 lbs. It doesn't appear to move the mast at all, (I could be wrong) but it REALLY tightens the headstay which improves up hill performance.
 

Ted

.
Jan 26, 2005
1,178
C&C 110 Bay Shore, Long Island, NY
I have a backstay adjuster and will load the backstay to about 7000 lbs. It doesn't appear to move the mast at all, (I could be wrong) but it REALLY tightens the headstay which improves up hill performance.
I strongly suggest that you check the size and breaking strength of your backstay. Loading it to 7000 lbs sounds excessive, if not dangerous. Generally you would not want to load the backstay more than 20% of breaking strength. For reference, the backstay on my 36 foot boat has a breaking strength of 8200 lbs and the maximum load induced by a backstay adjuster would be 1640 lbs.
 
Jun 5, 2010
990
Hunter 25 Burlington NJ
Standing the mast column-vertical is overrated. Most boats with headsail furlers suffer from either headstay sag or actual de facto forward rake, both of which I've seen very often (including today in fact) and either or both of which can be cured by imposing more rake.

Benefits to rake: tighter headstay; tighter jib luff; better pointing ability due to imposed weather helm. Also better appearance (boat just looks like it's raring to go). People who say 'Hunters don't point' are probably running heavy headstay furlers and limp maladjusted shrouds, netting negligible rake.

Hassles: lower boom end; sometimes needing to recut the main - but I would submit these people may already have considered it anyway for the dreadful bimini-top problem. Remember: reducing mainsail area negatively affects pointing ability - this includes for any reason including for headroom under the bimini. What do I bet the people with mainsails recut for the sake of the bimini are the same ones with heavy headsail furtlers who complain the boat doesn't point?

Short story long: I would suggest an imposed mast rake on a 37C of about 2 degrees, if - as has been mentioned - the mast partners will let you. Be sure to pin the mast foot into the step casting too!

With a cutter rig you have a viable option of imposing mast bend as well as imposing rake. A good backstay adjuster - given a keel-stepped mast - can work wonders. Tension the adjuster, tension the running backs, and your sagging headstay goes away, the boat points higher, and the staysail is effectively neutral to mast tension. Without a tensioned backstay (or with a too-heavy forestay), every time you set the inner jib you'll draw the mast forwards and see problems. I would go far enough to say if you have a cutter rig, you very much better have both running backstays and a backstay adjuster on the main one.
 
Jun 5, 2010
990
Hunter 25 Burlington NJ
I don't own a Loos gauge, so I do it by feel and probably tend to err on the slack side of tension. When sailing close hauled in 10 - 15 kt, my lee shrouds are a bit slack but not flopping around.
My brother and I, both guitar players, used to tune rigs harmonically. One guy each side - 'No; you're flat. Bring it up.... Maybe I'm too sharp.... That's it.'

I would love to have one of those gauges mainly to advise others and to have a better handle on the actual numbers; but your way and my way are perfectly adequate, providing we keep an eye on all the symptoms and - most importantly - the rig is all in tune with itself (it's a matter of proportion). When I worked at West Marine that rig-tuning gauge was the most-returned product in the store! - people bought it, used it, returned it for full refund (that irresponsible return policy being one of the major reasons WM has found themselves in catch-up mode now... but I digress).
 
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Oct 22, 2014
12,375
CAL 35 Cruiser Portland OR, moored EVERETT WA
irresponsible return policy being one of the major reasons WM has found themselves in catch-up mode now
Not sure it was the primary problem. I suspect management was the bigger issue. It is bad form to buy a thing, use it, then return it to the seller. If one sees such behavior the store can take action. But more likely the events are disconnected and the store workers found it easier to refund then not. Folks who buy/use/return figure they have a great scam.
 

Blaise

.
Jan 22, 2008
358
Hunter 37-cutter Bradenton
Sorry, 7000 should have been 1700 pounds. I always hate it when I sound like an idiot, even though my wife says I have a habit of it.
Blaise
 
Oct 22, 2014
12,375
CAL 35 Cruiser Portland OR, moored EVERETT WA
Worry not @Blaise, ‘‘tis the season to forgive and give grace”.
I for one am right beside you with the experience and a bride of 45plus years providing critical observation of me. :biggrin:
 
Jun 5, 2010
990
Hunter 25 Burlington NJ
Not sure it was the primary problem. I suspect management was the bigger issue. It is bad form to buy a thing, use it, then return it to the seller. If one sees such behavior the store can take action. But more likely the events are disconnected and the store workers found it easier to refund then not. Folks who buy/use/return figure they have a great scam.
It was store/corporate policy (at that time): if we sell it, and the item the customer brings back scans up, we refund him. Period. It did not matter if the customer was a 'registered' member; he would simply not produce his card (coming to not his usual store, so not being recognized) and the 'points' for the refund would not go against him. Happened ALL the time. I 'refunded' a guy about $700 one time for plumbing parts he clearly bought at Lowe's - but the policy is the policy. I gave the higher-ups (I was manager at the time) a whole lotta heck for that too; but they said it was small price to keep a customer happy (but he wasn't even our customer!). I was steamed about it - gave the customer a new card without telling him he'd just received a $700 hit to his credit points. Don't know if he ever figured that out.

But, as usual, I digress.:doh:
 
Jun 5, 2010
990
Hunter 25 Burlington NJ
Worry not @Blaise, ‘‘tis the season to forgive and give grace”.
I for one am right beside you with the experience and a bride of 45plus years providing critical observation of me. :biggrin:
How fortunate we are that our critics always outnumber our admirers!

'I don't want people telling me how it can't be done! I want people doing it!' - my soon-to-be son-in-law (theater-set designer and builder, whom I get to work with on 'off' days). :dancing:
 
Jun 5, 2010
990
Hunter 25 Burlington NJ
Sorry, 7000 should have been 1700 pounds. I always hate it when I sound like an idiot, even though my wife says I have a habit of it.
Blaise
Blaise, I kinda thought that sounded excessive. My engineer brother always seems to come up with phenomenally high stress figures for the rig. He figured our Raider 33 upper shrouds were loaded to 12,000. I said, the boat only weighs 9600! And what happens when shrouds get overstressed? - the boat heels over! I mean, duhh! - the water always yields, spilling off the load, so there is your friend. You can't stress the rig to breaking point unless you can keep it under full sail, under heavy conditions, and fully upright, to pose the maximum resistance to the load. And you've got to be either a complete cluck or a sorcerer to actually do that.

As a simple rule of thumb to gauge practical rigging stresses, look at the series of running-rigging blocks the manufacturer provided with the boat.
Schaefer '03' = 1000 lbs.
Schaefer '05' = 1500 lbs.
Schaefer '07' = 2000 lbs.

If that's too tricky for you, look at the size of the rope or size of the clevis pins - corresponds to the blocks.
'03'-series = 3/8" (3/16" pin).
'05"-series = 7/16" (1/4" pin).
'07'-series = 9/16" (5/16" pin).

I rigged most of my H25 with '05'-series, having calculated most of the sail loads at around 1250 (max). That would suggest the excellent '404' series, no longer made. I use '05'-series for sheets, halyards, and deck cheek blocks. I have a couple of '03'-series, mainly for reef and outhaul lines.

Anything you can't inspect easily (spinnaker-halyard block) or have any question about: scale up. Anything with more than a 90-degree bend: scale up (my foot blocks are '07'-series). Also, remember that wire rope sizes at one-half running-rigging sizes are way oversized for the actual loads. In general, you're in safe hands to load anything to 1/2 or 2/3 manufacturers' rated load, all other things being up to the task.

The next question, of course, is if the attachment points on the boat are up to the task; and gauging that is my stock in trade; but I'm here to provide the best general guidance I can without me charging you money or you wanting to sue me. ;)
 
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