Letting the car slap

[TrentePieds]

Northern:

Are you pressing ahead too fast? I see that you joined us in the spring of this year and, from another thread, that you are hoping to use time on a Cessna 185 on floats towards you certification as yacht skipper.

Given that you fly a Cessna you will already know the basics of aerodynamics. You will also know, or perceive, that a boat's mainsail in no more than a wing stuck up on end. It generates drive for the same reason a wing generates lift, i.e. the airfoil matters!

The problem with the “wing” on a boat is, however, that the airfoil gets buggered because the sail is soft rather than rigid, and that it twists. The twist in analogous to “wash-out” in a wing, but ideally the angle of attack should be the same all along the leading edge, in this case the mast. The track and car are there to assist you in achieving just that (reducing "wash-out"), although track and car is the LEAST important, necessary or effective of your mainsail controls.

Ideally you should be able to align your mainsail boom directly over the centreline of the boat. However, that cannot be done because the nearer the mainsheet comes to being in the centreline plane, the less effective it becomes in controlling boom deflection. When you are sailing HARD ON THE WIND you can compensate for that by hauling the car up to weather so the sheet is still oblique to the centreline as it is when you are further off the wind. Similarly, there are occasions when you get a better sail shape by letting the car come to leeward to furnish more of a downward acting force on the boom.

There are two things for you to think about: 1) The car is the LEAST important of the mainsail trimming devices, and it is possible that you are not yet at the level of sailing sophistication where having a track and car will make any difference to you at all. 2) The Mystic 30 is NOT a racing design, and she is really not in need of a track and car at all for the sort of sailing you'll be doing in that boat. The track and car are there only because it's considered de rigueur to have them. The Mystic 30 is only a five tonner, and she has about a 220 foot main, I would guess. So don't get too sophisticated for you own or the boat's good. And contrary to some opinions expressed here, there is absolutely NO need for a boom brake or any other fancy gear like that in a boat of this type and size. What is needed is that skipper has appropriate knowledge and PROPER TECHNIQUE!

So, at least for now, set the car on the centreline and jam it there by means of the adjustable stops on each side of it. LEAVE IT THERE. Now go out and bring the boat about (go from tack to tack with the wind coming over the bows) a few hundred times until it becomes absolutely second nature and doesn't need thinking about. Then wear the boat (go from tack to tack with the wind coming over the stern) a few hundred times until THAT becomes second nature. If you've been lucky, your Mystic 30 will be tiller steered rather than wheel steered which will make these learning curves far less steep.

You DON'T have to be able to trim sail to absolute perfection to be able to enjoy your boat immensely. She will serve you well even if you are a raw beginner. That is just the nature of that boat's design. So as I said: Take her out, set the mainsheet car in the centre and sail the heck out of her. As you gather experience, come here to ask any question you like. You will find someone here who can give you a good answer. But always remember: KISS! And don't believe the guff you read in the glossy mags. The gear that's advertised there is not something a novice needs. What novices need is good advice and lots of practice :-)

All the best,
TrentePieds

[NorthernMac]

Originally Posted by TrentePieds

Northern:

Are you pressing ahead too fast? I see that you joined us in the spring of this year and, from another thread, that you are hoping to use time on a Cessna 185 on floats towards you certification as yacht skipper.

Given that you fly a Cessna you will already know the basics of aerodynamics. You will also know, or perceive, that a boat's mainsail in no more than a wing stuck up on end. It generates drive for the same reason a wing generates lift, i.e. the airfoil matters!

The problem with the “wing” on a boat is, however, that the airfoil gets buggered because the sail is soft rather than rigid, and that it twists. The twist in analogous to “wash-out” in a wing, but ideally the angle of attack should be the same all along the leading edge, in this case the mast. The track and car are there to assist you in achieving just that (reducing "wash-out"), although track and car is the LEAST important, necessary or effective of your mainsail controls.

Ideally you should be able to align your mainsail boom directly over the centreline of the boat. However, that cannot be done because the nearer the mainsheet comes to being in the centreline plane, the less effective it becomes in controlling boom deflection. When you are sailing HARD ON THE WIND you can compensate for that by hauling the car up to weather so the sheet is still oblique to the centreline as it is when you are further off the wind. Similarly, there are occasions when you get a better sail shape by letting the car come to leeward to furnish more of a downward acting force on the boom.

There are two things for you to think about: 1) The car is the LEAST important of the mainsail trimming devices, and it is possible that you are not yet at the level of sailing sophistication where having a track and car will make any difference to you at all. 2) The Mystic 30 is NOT a racing design, and she is really not in need of a track and car at all for the sort of sailing you'll be doing in that boat. The track and car are there only because it's considered de rigueur to have them. The Mystic 30 is only a five tonner, and she has about a 220 foot main, I would guess. So don't get too sophisticated for you own or the boat's good. And contrary to some opinions expressed here, there is absolutely NO need for a boom brake or any other fancy gear like that in a boat of this type and size. What is needed is that skipper has appropriate knowledge and PROPER TECHNIQUE!

So, at least for now, set the car on the centreline and jam it there by means of the adjustable stops on each side of it. LEAVE IT THERE. Now go out and bring the boat about (go from tack to tack with the wind coming over the bows) a few hundred times until it becomes absolutely second nature and doesn't need thinking about. Then wear the boat (go from tack to tack with the wind coming over the stern) a few hundred times until THAT becomes second nature. If you've been lucky, your Mystic 30 will be tiller steered rather than wheel steered which will make these learning curves far less steep.

You DON'T have to be able to trim sail to absolute perfection to be able to enjoy your boat immensely. She will serve you well even if you are a raw beginner. That is just the nature of that boat's design. So as I said: Take her out, set the mainsheet car in the centre and sail the heck out of her. As you gather experience, come here to ask any question you like. You will find someone here who can give you a good answer. But always remember: KISS! And don't believe the guff you read in the glossy mags. The gear that's advertised there is not something a novice needs. What novices need is good advice and lots of practice :-)

All the best,
TrentePieds

Thanks!

I'll do just that, the thing I didn't understand is with the track the boat already has, how one would adjust the car under sail, it's not the biggest main but I'd have a heck of a time man handling it over to move a stop while there was any power in the sail, for now I'll just pin it center.

The other thing that was added on, I think, was that rail for the staysail to track on, anything I should be doing differently for that?

The boat will be a liveaboard for me, since I travel every 6mo for work, I've spent a good amount of time on the water, just it's been a while so some rust needs to get knocked off and ofcourse there are things I still need to learn, no doubt.

As for moving ahead too quickly, we only have so much time before we hit our experiation date, I fully want to take the time to learn and believe 100% in the importance of a good foundation, but I also want to move with purpose, if that makes sense

[a64pilot]

Originally Posted by CassidyNZ

My boat and I believe the majority of boats, have lines in a block system on both sides of the car on the main sheet traveller that allow setting of the car in a specific spot. It only has stop blocks at each end of the traveller to prevent the car going AWOL.

The absence of these lines means one has to man-handle the car to the desired position with a drawing main and then position the stop blocks to hold it there. On a 37 ft boat this could be quite difficult and even moderately dangerous in anything but light winds.

Or perhaps I’ve misunderstood the situation.

You have actually described my boat, for some reason there are no lines to the car, you have to position the car with no load on it and then move the stops, and yes you have to be careful as of course the sail is much stronger than you.
Due to the parts required not being in production I’m having to replace the whole traveller. Rig rite said they would have the parts in spring I think.
It’s going to arrive from Sweden on the 14th of Nov. err it’s past isn’t it?

[TrentePieds]

Quote: " the thing I didn't understand is with the track the boat already has, how one would adjust the car under sail,"

'Sbecause there's nothing TO understand :-)

You don't reposition the car while you have a weight of wind in the sail. The deeky little "hauls" on the car never give you enuff mechanical advantage to do that, so don't even bother to try. The need to reposition is quite rare, so you do it while the sail is luffing. Remember you are CRUISING, not racing, so there is no need to get unduly excited :-). S'pose you are on a nice beam reach in 15 knots. Just bear up till the main luffs. Grab the entire sheet tackle down near the car, haul it up to weather using brute force and reset the stop. Leggo the sheet. Fall off to the heading you had before, and Bob's yer uncle. As I said in my last post, it's not about the gear you have. It's about the technique you have :-)!

Your track for the staysail is a kettle of fish of a different colour. To understand this you need to think about your staysail as if it were slats on an aircraft's wing. Back before cruising rigs were corrupted by the notion that every boat has to be a racer, one function of the staysail on a cutter was (as it is now) to ensure that the flow on the “backside' of the mainsl (the upper surface of the wing) stayed laminar. Therefore the shape of the staysail, the twist, had to be controllable so as to optimize the “slot effect” all the way up the leading edge (the luff) of the main, which was the sail that provided the drive. That meant that the downward force acting on the staysl LEECH had to be applied some distance off the centreline of the boat because the angle of INCIDENCE of the staysl necessarily had to be smaller than that of the main. That was achieved by having several attachment points on deck for the staysl sheets. That in turn led to the convenience of the “clubfooted” staysl with a boom and a thwartships track and car for the attachment point for the staysl sheet. So the staysl sheet car you set where the twist in the staysl will give you a nice even slot all the way up the mainsl. You know you've got it right when the telltales on the LEE side of the main (the upper side of the wing) lie nice and quiet. Again, why struggle to do that with wind in the sail? Just luff it, reset the car, then tauten sheet again.

If you really want to understand these things, pick up a copy of C.A.Marchaj's Sail Performance: Techniques to Maximize Sail Power. It's expensive, but worth the money if you want to get scientific about these things :-)

Cheers

TP

[thinwater]

OP: You didn't say if you had a vang to hold the boom down. I assume you do, since otherwise the sail can twist crazily, which is neither efficient or good for the rigging (chafe and risk of Chinese jibe).


For heavens sake, get a real traveler. It's a tiny item is vital to learning sail trim. It also makes sailing smother and safer:
* Less boom banging in light winds.
* Better control of sail shape in high winds, which leads to increases safety.

* Reduced boom travel during accidental jibe (if the traveler is locked to leeward the boom does not go as far).

[a64pilot]

Originally Posted by TrentePieds

Quote: " the thing I didn't understand is with the track the boat already has, how one would adjust the car under sail,"

'Sbecause there's nothing TO understand :-)

You don't reposition the car while you have a weight of wind in the sail. The deeky little "hauls" on the car never give you enuff mechanical advantage to do that, so don't even bother to try. The need to reposition is quite rare, so you do it while the sail is luffing. Remember you are CRUISING, not racing, so there is no need to get unduly excited :-). S'pose you are on a nice beam reach in 15 knots. Just bear up till the main luffs. Grab the entire sheet tackle down near the car, haul it up to weather using brute force and reset the stop. Leggo the sheet. Fall off to the heading you had before, and Bob's yer uncle. As I said in my last post, it's not about the gear you have. It's about the technique you have :-)!

For the last five years that is what we have been doing, other projects and cost have just been prioritized over the traveller, now we are finally going to be getting a “proper” traveller.
However the idea of placing it in the center doesn’t work, cause you often want the boom centered and of course no matter how tightly you tighten the line and increase stresses doing so, you can’t get the boom directly over the car, so you do end up moving it every tack.
There is a lot of power in that sail of course and the boat can easily fall off so you have to be careful.
For four years I did it without a boom brake, I’ve had the brake for about a year now and find it to be a safety thing, it helps hold the boom steady when the sail is luffing if the boat is rocking in a seaway.
Maybe an unconventional use for a brake, but I leave it there always and maybe not tightened down so much it’s a preventer but run just a little looser and it will control the boom from swinging back and forth, but won’t stop it from being moved by the sail, with a heavier furling boom, especially when reefed and the weather up, having it not swinging around is I think safer.

Anyway assuming Selden ever actually ships the thing we will soon have a proper traveller system.

[TrentePieds]

A64:

I don't disagree with anything you say. But "baby steps", eh :-)?

I keep harping on technique. I'm a firm believer that you need to be able to do handle your boat without the fancy gizmos :-). Once you can do that, by all means go ahead and blow away as much money as you like on doo-dads that you no longer need. By then, they have been reduced to mere conveniences. Remember that even into my time we handled boats that by our standards were quite heavy and clumsy without any of the modcons :-) Our friend Northern has a five-tonner, as do I. You have a 10 tonner. There is quite a difference in the forces you have to deal with. Your main has 50% more area than his, and your fore-triangle likewise. Your ballast ratio is 50%, Northern's is 30 or 35%. You have lotsa deadrise, Northern doesn't. All these things affect what is possible and what is efficacious in terms of technique. In a five tonner you can still use a lot of techniques inherited (or transferred) from dinghy sailing. In a ten-tonner you can't.

Frinstance: My advice to grab the mainsheet and haul the car to weather by brute force will work for Northern, tho it doesn't work for me and it wouldn't work for you. The reason is that Northern's track is WAY aft at the end of the boom, so he has to haul only with the force required to counteract the weight of wind in the sail. MY track is on the house top halfway along the boom, so I would have to haul with TWICE the force that Northern would have to apply, given that our mains are the same area. Your main has 50% more area than either N's or mine, so even IF your track was at the end of your boom (which I don't recall that it is) you would have to haul with 1.5 x 1.5 = 2.25 times the force that N has to. Well, I know from experience that now in my dotage I'd run out of strength before I could get the job done. A further consideration is that N can stand securely in his cockpit to do it. I would have to do it from the narrow side deck alongside the house which means that if I muff it I might well go for a swim. But I'm a cruiser, so I can simply luff up while I do it without having to break a sweat :-)

All this means that we cannot give pat answers to questions like Northern's. So much depends on the particular boat and the particular skipper, My purpose has been to set N thinking along certain lines. I think that given that N's background is flying, as “A64” indicates that yours is, there are things that bear thinking about in the transition from airman to sailor. It isn't common for airmen to do their own maintenance. It simply isn't a viable option. Sailors most often do as much of that as they can. N had posted some questions earlier in the month indicating that he is not conversant with boat maintenance. Not a problem. It just means that we here on the forum have more opportunities to set him thinking along lines that are useful for the seafaring man :-)!

TP

[Jim Cate]

TP, I can't agree that a traveler is unimportant on a 30 foot sloop. IMO, it is an essential part of sail control... true on all sailboats from dinghies to big keelers.

So, my contrary advice to the OP is to fit simple control lines on his traveler and learn to use them... it's part of basic sailing. One can always use the control lines to fix the traveler at the center line if desired for simplicity. The cost of a couple of small blocks and a few meters of line shouldn't break the bank and the benefits are significant.

And do be careful with the airplane wing analogy, TP. Airplane wings are operating in a different flow field than sails. The apparent wind velocity is pretty constant along the leading edge of a wing while for a sail there is a very significant difference in velocity between the boom and the masthead. This is why twist in the sail shape is so important to sail trim... "washout" ain't a problem here. And controlling twist is part of the job of the traveler!

Jim

[Tillsbury]

ahha, I see it now, there are no controls for the traveller. It’s not really designed to slam against the stops, as that exerts way too much impact on everything. You’re right to dislike that.

Set the pair of stops so the traveller is in the centre.

If you’re going deep downwind, you can let the traveller down to let the boom out more while retaining a little vertical force on it.

If you’re going hard upwind, you might want the traveller further towards the wind. In that case, do something similar to what I suggested, in that you point a little too high in order to release the pressure on the sail, then let the traveller way down away from the wind. Then move the other stop so the car is trapped there. Then tack, and the main sheet will now be on the “high” side which gives you the ability to pull in the sail without flattening it too much.

[wingssail]

Originally Posted by TrentePieds

Northern:

...The track and car are there to assist you in achieving just that (reducing "wash-out"), although track and car is the LEAST important, necessary or effective of your mainsail controls.

Ideally you should be able to align your mainsail boom directly over the centreline of the boat. However, that cannot be done because the nearer the mainsheet comes to being in the centreline plane, the less effective it becomes in controlling boom deflection. When you are sailing HARD ON THE WIND you can compensate for that by hauling the car up to weather so the sheet is still oblique to the centreline as it is when you are further off the wind. Similarly, there are occasions when you get a better sail shape by letting the car come to leeward to furnish more of a downward acting force on the boom.

There are two things for you to think about: 1) The car is the LEAST important of the mainsail trimming device...

Respectively, but totally, disagree. Traveler control is very beneficial on any mainsail.

In light air the traveler can be centered. Then with the main sheet you can pull the leech closed but not too closed. Just open enough to keep tell tales flying on the leech of the main (if you don't have these, add them).

In some circumstances you may pull the traveler above center and ease the mainsheet more, to keep the sail centered but allow the leech to be open.

In heavier air you can ease the traveler way down to reduce weather helm (this is a very fast way to sail).

So a traveler that can be adjusted under load is very useful. Probably a 4:1 pulley system with a jam cleat on deck at the end will do. You don't need an expensive traveler car system, just some small blocks you can tie or shackle in place.

If you don't put some control lines on the traveler at least put some rubber stops to reduce the impact.

YOU CAN adjust your existing traveler while sailing: Move the windward stop then tack and adjust the other one. However this will not allow you to easily position the traveler above centerline.

[a64pilot]

[QUOTE=TrentePieds;3025844]A64:
It isn't common for airmen to do their own maintenance. It simply isn't a viable option. [QUOTE]
It’s a lot more common than you may think. First pilots in the US are allowed to do preventative maintenance which means things like changing oil, spark plugs, timing magnetos, changing tires, even painting.
Then quite a few are like me, I spent five years in Maintenance before flight school and was an A&P before I was a pilot.
It’s s lot like “Yachts” a very great many won’t get their hands dirty, they call a mechanic, many will tell you that they make too much money to do menial work.

[wingssail]

Originally Posted by a64pilot

It’s s lot like “Yachts” a very great many won’t get their hands dirty, they call a mechanic, many will tell you that they make too much money to do menial work.

I've actually never heard that said.

Mostly people don't know how to do it, or don't want to get dirty in a hard task, AND they have the money to hire someone. And honestly, they think the tradesman will do a better job (they lack confidence in their own skills). I think only a snob would think it is menial, beneath him. There are a few cruisers who are snobs, but not many.

But maybe it amounts to the same thing.

One day I was driving by a boatyard in Seattle and I saw a very large racing yacht in the stands. I turned in to see what work was being done.

There was the owner, very wealthy, working on the keel himself. I said, "Why are you doing this work?"

He answered, "I can't get anyone to do it the way I want it done."

So I took away three thoughts:

There is no shame in doing it yourself, even if you can afford to pay another person.

And, if you want it a certain way you are best off to do it yourself.

And, there is a certain pleasure in knowing you did it.

Now I do my own woodwork. It's not craftsman like, but I did it.
I do my own canvas work, it looks "home made", but I did it.
I repair my own sails and design new ones, that I do well.
I fix every thing I can, from electrics to electronics, mechanical, plumbing, everything.
In Mexico labor is cheap. I could afford to pay someone.
But when I do it, I get it the way I want (right or wrong).

And when the boat breaks down in some third world port, I have it up and running immediately. That I can do.

Fix it yourself.

[JPA Cate]

^^^^Oh, yes, if at all possible, that's the gold standard.

However, I must admit that at over 80, there's a certain satisfaction to hiring some of the grunt work done. One does watch closely, probably are thought the owners from hell.

Ann

[NorthernMac]

Mx wise I do all I can do on my own plane, including owner assist annuals with my mechanic.

On the work planes there is only so much I can do as they are on a 135 certificate.

[NorthernMac]

Originally Posted by thinwater

OP: You didn't say if you had a vang to hold the boom down. I assume you do, since otherwise the sail can twist crazily, which is neither efficient or good for the rigging (chafe and risk of Chinese jibe).


For heavens sake, get a real traveler. It's a tiny item is vital to learning sail trim. It also makes sailing smother and safer:
* Less boom banging in light winds.
* Better control of sail shape in high winds, which leads to increases safety.

* Reduced boom travel during accidental jibe (if the traveler is locked to leeward the boom does not go as far).

No vang