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PostPosted: Sat Jun 26, 2021 8:01 pm 
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Matt Miller, What is the popular belief regarding mast rake on my 1986 h18 . I was told that backward rake would lessen potential for pitchpoling yet, others suggest the opposite.. Would you clear this up for me,please??? Thanks Deejay


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PostPosted: Mon Jun 28, 2021 5:32 pm 
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I can give you my 2 cents on Hobie 18s regarding pitchpoling. First, the Hobie 18 is the least likely catamaran out there to pitchpole. The bow design on the boat was to specifically prevent that (in my view),

Next, mast rake will have very little effect on whether you pitchpole the boat. The largest impact on the boat having a tendency toward a pitchpole will be determined by crew weight location or water in the hulls. The first ingredient needed is big wind. There will need to be significant wind to set up a situation where one might become concerned about pitchpoling. You will not be in any danger unless you are driving off on a reach in big wind. If you get lifted up on a big wave and are surfing down that wave and the crew does not move weight towards the back of the boat then you will have risk of a PP. In this same situation, if you have a lot of water in the hulls, that water will rush forward when angled down and can cause the bows to dig under water. What I have seen take a boat over is when you are turning, say the windward mark and going on a reach with a crew member on the wire (or both) and they have no way to keep themselves in the back of the boat. They will swing in the trap to the front of the boat and the result of that weight going forward will add to wind pressure on the main and can result in a PP. In these examples it will not matter about your mast rake.

By the way the general rule is you rake the mast back for ability to point up wind better, however that will depower you down wind. It is a trade off, so which area do you want your strength, up wind or down?

When I sail up wind I try to have the leeward hull about 1 inch from going under. As wind builds and it starts to go under water, I start moving weight back also trying to maintain that 1 inch of the front of the hull above the water.

Also as a safety note, even going dead downwind, if the wind gets high enough (30+) all of that pressure will be pushing on the main, which will push down the front of the boat. There is a point where the hulls will go under and any boat will PP, including monohulls. This is why boats will shorten sail in heavy air. In these extreme conditions, if there was some lift in the front of the boat from a spinnaker, then the boat will be more balanced from the pressure that is pushing on just the main, which will provide lift to the front and one can survive longer, until well... you don't :D

Bottom line the Hobie 18 is the safest boat from a Pitchpoling perspective. I have stuffed the hulls into the water up to the front cross bar without going over. The boat just stopped, backed up out of the water and took off again.

Again, how far you rake your mast is not about pitchpoling.

Cheers, and good luck.


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PostPosted: Mon Jun 28, 2021 7:43 pm 
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Kaos Thanks for the great info...DJ


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PostPosted: Tue Jun 29, 2021 2:33 pm 
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Agreed with all of Kaos's comments above.

Raking the mast back really doesn't prevent a pitchpole... it's primarily a way to get a better pointing ability by moving the center of effort on the sails further aft, but it also increases weather helm significantly. For this reason, I don't like to run my mast too far back because I start to feel like I'm fighting the tiller the whole time. In theory, the aft rake also very slightly reduces how "tall" your mast tip is above the water, slightly reducing the boat's downwind speed/performance. However, it's not appreciable enough to affect whether the boat will pitchpole or not... if you've got enough wind to pitchpole an H18, the mast rake won't make a difference.

To add to the comment about the H18 not really pitchpoling, I have to agree that it's very tough to do. Downwind, I too have stuffed the hulls all the way to the front crossbar and it's come right back up on me. I even stuffed a bow once while double trapped and turning downwind around the windward mark in a race... the crew and I got thrown forward around the forestay, and the boat STILL didn't pitchpole! It came back upright, with the two of us hanging off the jib roller furler like some bizarre figurehead. :lol:

I have pitchpoled my H18 exactly once in 8 years of sailing it, and it was screaming along downwind with a gust of 30+ mph and fighting a 4 mph current. The crew and I were even sitting on the rear crossbar, but we didn't stand a chance.

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'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
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PostPosted: Wed Jun 30, 2021 7:12 am 
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I can agree with the above. Never pitch-poled my 18. It will bury the hull and just stop, like a punch in the face. It may go over on it's side or just come up and go again. depends on how fast you can get the sails released and how quick your crew can shift weight. If the hull is that close, and watching the water, the weight should be already be hiked out and way back. I have the crew hang on with the big bungee righting line in case it does bury, they don't go flying forward.


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PostPosted: Wed Jun 30, 2021 8:31 am 
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Years ago, during Club Racing, on my old SX18, with a Tiger spin, and we got hit by a gust - no problem.
The bows dug in, the sterns rose to about 60 degrees, we held on tight, the boat settled, and we carried on racing.

For mast rake, make a mark up the mast, 48" above the base.
From that mark, measure to the bow tangs, and 'set' the rake somewhere between 103" and 107".
Then you are good to go.

I miss my old 18.....what a wonderful beast.

Happy Canada Day

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2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'


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PostPosted: Thu Jul 01, 2021 5:26 pm 
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REGARDING MAST RAKE AND 'PITCHPOLE'... My question on the term 'pitchpole ' may have been confusing . I meant to refer to the term "cartwheel' which refers to burying only one hull (usually on a screaming reach with bad weight distribution). As I read your post replys I got the impression that I mislead you( Kaos, Saborsforthecup,raisehull,and John Lunn). I apologize!!! Would you please give your opinions on Mast rake and effect on Cartwheel potential on the H18? Thank you all for your time...Deejay


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PostPosted: Fri Jul 02, 2021 5:20 am 
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Been there, done that....
Do your best to retain good trim on the boat, keep the weight towards the stern.
If one bow digs in, do your best to turn downwind, and release the main sheet and the jib sheet instantly.
If you can't, be prepared to swim.

good luck

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'


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PostPosted: Fri Jul 02, 2021 7:56 am 
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deejay wrote:
REGARDING MAST RAKE AND 'PITCHPOLE'... My question on the term 'pitchpole ' may have been confusing . I meant to refer to the term "cartwheel' which refers to burying only one hull (usually on a screaming reach with bad weight distribution). As I read your post replys I got the impression that I mislead you( Kaos, Saborsforthecup,raisehull,and John Lunn). I apologize!!! Would you please give your opinions on Mast rake and effect on Cartwheel potential on the H18? Thank you all for your time...Deejay


I didn’t get the impression from reading this thread that any of the responders misunderstood your question. I think the general opinion is that the H18 is in fact a very difficult boat to pitchpole. It handles much differently from a H16, which will stuff a bow if you so much as sneeze in the wrong direction.

I’ve sailed and raced H18’s for over 30 years and I think there was maybe once in all that time where I did a full on pitchpole. The boat just doesn’t want to capsize that way. If you are on a broad reach, generally both bows will go under and bury up to the crossbar, the boat will come to a stop, pop back up, and keep going. If you are on a beam reach, the leeward bow may dive, but the boat will pivot and roll over onto its side as with a “normal” capsize. It doesn’t want to do a cartwheel. Maybe in large ocean conditions pitchpoling would be more ofa concern, but for general inshore sailing, it shouldn’t be much of a problem.

To your original question about mast rake, my setup is such that with a non-low profile mainsheet setup (i.e., a single triple block on the boom and a triple over single hexaratchet on the traveler), I am nearly block to block when fully sheeted upwind in strong wind. So essentially raked about as far back as I can go with standard blocks and forestay length. I find this amount of rake to give a good balance of upwind and downwind performance with a nicely balanced helm and I keep this setting for all conditions.

sm


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PostPosted: Mon Jul 05, 2021 10:28 am 
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Well if you had a good understanding of how to sail downwind in big air from a beam reach and on down the circle, I think you could prevent a pitchpole pretty reliably in up to maybe 25kts of wind in whatever beach cat you want if you are sailing for fun. Your rake will never be the sole reason for losing control but how you setup your boat and trim your sails will make a big difference in how the boat feels and how much work it is to prevent a capsize or face plant.

I've soloed in 25kts a bunch of times and seen how the boat behaves compared to having full crew weight with both a forward a raked mast. If anyone tells you that raking a mast forward is going to help prevent a pitch pole then I'd disregard anything else they say about sailing a catamaran. That's going to make it way worse. I've read just about every cat sailing book commonly out there and they all say the same thing regarding mast rake.

If I go out in heavy air I rake the mast back and it's easy to feel the difference in how hard you have to work to keep the bows up. Upwind you won't ever notice a real difference. Heavy rake upwind will make the sailplan have a bit less drag but you also move the center of pressure from the sailplan farther behind the center of resistance which will increase your helm but even that doesn't seem to be excessive to me. Downwind it should be common sense that moving the center of pressure away from the bows will add stability.

From what I've seen stuffing a bow is from doing one or all of the following:
-Not being fat enough. If you have a ton of weight sitting in the back of the boat you are pretty safe in almost anything. If you have above 375-400lbs on the back then you probably don't know what everyone else is complaining about downwind.

-Sailing deep downwind above 20kts with the traveller way down. If you want to take pressure off the bows you travel back up to the hiking strap and sail a little higher so that the force vector for the mainsail lift isn't angled so far forward on the boat. You should sheet the main so that it's not folded over the stay, and instead has shape in the bottom 1/3, and the rest is twisted off straight into your apparent wind. That way a gust doesn't immediately overload the bows and instead tries to force the boat over sideways which should be no big deal to prevent.

-Reacting to a big puff, after the hull is lifted, by driving the boat deeper. Going deeper in the puffs in most wind works. Especially if you have plenty of burgers sitting on the back. Going deeper when the hull is a foot in the air and rising is asking for disaster. As the boat flies a hull and rotates, the rudders start having a component of their force act like an elevator. When you pull on the tiller to drive deeper it will lift the stern and force the bows down even deeper. If you are slow to react, and most pitch pole kinda people probably are, this will be the nail in the coffin. Even if you could drive the boat deeper, possibly stall the main, and allow both bows to take the force from the sailplan, you are just relying on hope. Hope that the bows can resist the pressure. You have no direct control from a faceplant if you sail like that in really heavy air. In these cases when your bow is going under and you start flying a hull, you do the opposite and slam the tiller forward which will shoot the stern of the boat down in the water and pop your bows up, the boat will round up a bit and start to fly a hull higher. Simple solution to that is blow some mainsheet, set the boat back down and then drive it back to your original downwind course.

When people tell me "I just can't sail downwind in xxxx air" the answer is yea, stop sailing downwind. You don't have unlimited buoyancy in the bows so you have to stop going so deep and eventually start going downwind on higher and higher reaches.

If I am light on the boat then I furl the jib. The detriment of extra power seems to far outweigh the limited beneficial lift the jib gives the bows. Reducing sail area is almost always going to be a good thing if you are overpowered. I sail mostly the same when unirig. The boat will be more sensitive to the rake and will hobby horse a little more but as long as your dont drop the traveller all the way down like I mentioned before it should feel more comfortable. Just know how to back a boat through a tack because you are going to be stuck in irons almost every time. You will be a little farther off the wind to stay powered up but the nice thing is when you blow the mainsheet you are dumping the entire sailplan instead of having the jib still in tight.

That's my advice for fun sailing. If I am racing then yea, you probably are leaving up the jib, and are driving the boat as hard and deep as possible and are more or less intentionally trying to get as close to a pitch pole as possible. You don't really need to make a mistake to face plant the boat if you are playing that game. More like rolling the dice.


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PostPosted: Thu Jul 08, 2021 10:08 am 
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srm wrote:
deejay wrote:
REGARDING MAST RAKE AND 'PITCHPOLE'... My question on the term 'pitchpole ' may have been confusing . I meant to refer to the term "cartwheel' which refers to burying only one hull (usually on a screaming reach with bad weight distribution). As I read your post replys I got the impression that I mislead you( Kaos, Saborsforthecup,raisehull,and John Lunn). I apologize!!! Would you please give your opinions on Mast rake and effect on Cartwheel potential on the H18? Thank you all for your time...Deejay


I didn’t get the impression from reading this thread that any of the responders misunderstood your question. I think the general opinion is that the H18 is in fact a very difficult boat to pitchpole. It handles much differently from a H16, which will stuff a bow if you so much as sneeze in the wrong direction.

srm is correct, I understood what you meant by "pitchpole" just fine. Put simply, mast rake has no effect whatsoever on the potential to pitchpole or "cartwheel" the Hobie 18, because the H18 doesn't pitchpole except in conditions that far exceed the normal sailing conditions for the boat. Stuffing a bow will not cause the boat to cartwheel, whether the mast is raked back or perfectly perpendicular to the boat. Even if the crew is much too far forward, the boat just doesn't cartwheel... it comes to a stop, and either the bows come back up or the boat blows over onto it's side. The mast doesn't hit the water going forward.

I've been in the exact situation you described: stuffed the bow on a screaming reach (trying to bear off) with crew weight too far forward and the both of us on the trapeze flying a hull. The boat came to a DEAD stop, the crew and I were flung forward of the forestay, and even with 300 lbs crew weight swinging forward of the bows and the pressure of 20kts of wind on the mainsail, the boat DID NOT cartwheel. The bows came back up, and the boat continued to sail with the two of us hanging off of the forestay, that is how much buoyancy is in the bows of the H18. It eventually capsized over to the side without enough weight to windward.

Against my better judgement, I'll post the photos below for added clarity:
Image

https://photos.google.com/share/AF1QipM ... NLbVFuNG5R

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Mike
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'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238


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PostPosted: Thu Jul 08, 2021 7:31 pm 
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SabresfortheCup wrote:
Put simply, mast rake has no effect whatsoever on the potential to pitchpole or "cartwheel" the Hobie 18, because the H18 doesn't pitchpole except in conditions that far exceed the normal sailing conditions for the boat. Stuffing a bow will not cause the boat to cartwheel, whether the mast is raked back or perfectly perpendicular to the boat. Even if the crew is much too far forward, the boat just doesn't cartwheel... it comes to a stop, and either the bows come back up or the boat blows over onto it's side. The mast doesn't hit the water going forward.


I think a simpler way to accurately describe the situation is that all things being equal, raking a mast farther forward will put more pressure on the bows and make it easier/more likely to dig a bow in. The heavier the air rake the mast back a few holes on the chain plate, not because you will pitch pole otherwise, but because it adds stability and you can push the boat harder.

I've seen an H18 stuff a bow and pitchpole twice, both with over 300lbs of crew so I wouldn't say the boat wont face plant if it stuffs a bow. All depends on if before/as the bow is digging in, the skipper is depowering in the puff, their till reaction, etc. The passive safety built into slightly bigger bows isn't idiot proof.


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PostPosted: Fri Jul 16, 2021 5:11 am 
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Hi all, I hope everyone is doing great. Greetings from Down Under.

If you are worried about burying the bow on a beam reach or downwind, I strongly recommend lifting the windward dagger board 100% and also lifting the leeward dagger board 50% to 100% depending on the sailing angle. Beam reach = 50%. Downwind (90 degrees apparent wind) = 100%. Reducing the side load created by the dagger board wipes off pressure and forward speed and greatly helps preventing nose diving. It can also help greatly if you are at the top mark and it’s really windy and you want to bear away and are concerned about capsizing. Pause the boat, lift the boards up, then bear away.

Also, I run HEAPS of mast rake in all weather conditions. It’s totally awesome. And I highly recommend it. Photos of my mast rake measuring can be found on my boats own Facebook page in the link in my foooter. After putting in the ton of mast rake, I re jigged my rudder rake to get the helm neutral again. Photos are also posted of my rudder rake.

I hope you’re having fuuuuuun……..

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Hobie 18 Reimagined
Sail # 490
Boat name: 18@heart
http://www.hobie18.fun
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PostPosted: Sat Jul 31, 2021 2:28 pm 
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Now THIS, is a "pitchpole". https://www.youtube.com/watch?v=L1MnPadNmJI


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