Basic Spinnaker questions

[FairweatherDave]

So in the good weather of last weekend with a gentle easterly approaching the Solent my wife was persuaded that I could hoist the spinnaker. Result! This involves me rooting around below for all the stuff required and then reading my notes on how to rig. In this department I am very much a newbie. Much to my joy we got the sail up without any problem behind the genoa. Now the challenge was to fly it for as long as possible and build experience. But we also needed to get through the submarine barrier and past Portsmouth and Gillicker, so holding a course was a perhaps a broad reach rather than a training run. From previously posting on this subject I know the pole should be in line with the boom and I was able to just hold it off the furled genoa. After that I focused on keeping the sail up with the luff occasionally breaking at the shoulder, and keeping the two corners level. However what I have just been reading about is that the luff should be vertical from the end of the pole.....from the photos I took I can see the pole should have been even more forward (as stated not possible) because the luff was definitely leaning inside the pole. Presumably the purists would say in that case I shouldn't have been flying the spinnaker? All I can say is it seemed to work pretty well.
A secondary question is the height of the top of the sail. I have no idea if the spinnaker is the right size for the boat, it may be a little small. Just trying to get the sail to look right I did not hoist completely to the top (maybe 3 or 4ft short). The pole was pretty much at the bottom of the track on the mast with the goal being to have it horizontal. Should I have hoisted all the way and set the height of the pole after that? Any guidance appreciated as always.....

 

[Buck Turgidson]

I’m no expert but I think the pole should be 90degres to the wind. Boom will be where it needs to be but limited by standing rigging

 

[john_morris_uk]

I’m no expert but I think the pole should be 90degres to the wind. Boom will be where it needs to be but limited by standing rigging

That's my understanding, (although I'm not the last expert in spinnaker trim!)

Height of pole is more to do with which bit of the luff of the kite is curling first IIRC. It's about wind flow across the sail and less about keeping the corners at the same height. (After all in light winds, the shackle and spinnaker sheet might drag the clew down - which is why some race boats have a choice of spinnaker handling gear.)

 

[RJJ]

Good work so far. You're asking the right questions.

Fore-and-aft. "Pole in line with boom" describes the mechanical relationship, between the two very well as you change points of sail. But in practice you should trim each sail separately for best effect. On a beam reach, set the pole so it's inches off the forestay - having allowed for stretch in the guy, especially if it's not posh dyneema. Then, as you bear away a little, you've no doubt been told to ease the sheet until the luff is just curling - in fact, and ideally, you want to ease the sheet and trim in the guy in concert. Up to you if you can be bothered ;-) it's easy when you have a few extra people, harder when short-handed.

On a deep broad reach, you're trying to square the guy back to maximise projected area. The constraint is, as you square the guy you need to pull in the sheet as well to prevent collapse; at some point it will be clear you have stretched the foot too tight and it's rubbing on the forestay. To run square, you might square the pole back as much as 75 degrees, but it will vary according to the geometry of pole length and spinnaker width.

If the luff curls too much because the wind shifted forwards (or the wind drops, known as a "velocity header") it's worth knowing you re-establish flow and prevent collapse much more quickly by easing the guy a foot (as long as it's not on the forestay) or so than by pulling in the sheet. Once you've stabilised the spinnaker, you can adjust all settings (including course steered) in slower time, more smoothly and without having to shout "GRIND!" which is irritating for everyone on board, particularly the person being yelled at.

Hoist of sail: I can't think of a reason not to fully hoist. It stabilises the sail (stops it gyrating around the mast); puts it into stronger wind. Hoist the sail fully; raise the pole up the track. There is an argument to set the halyard shackle with a "boggle" so that the knot/splice is a matter of a inch or two from the sheeve and less likely to get chewed / stuck.

Pole height: "clew and tack level" is again a starting point, but you want to sail efficiently, right? Post #3 is correct - you want the luff to curl evenly. If the luff curls at the bottom, pole up; if it curls at the top, pole down. On a reach, the clew is likely to be lower; on a run, the clew is likely to be higher. The exception would be if you're trying to beam reach in powerful conditions, at which point you want to think of the spinnaker like a genoa; tensioning the luff (pole down) has the effect of opening the upper leech, depowering the sail, and helping you point. But for cruising purposes, you'd probably not choose the spinnaker for those conditions.

Pole height: running in a breeze / waves, it can be worth trimming both clew and tack downwards to help stabilise both the spinnaker, and the entire yacht. You can either use the lazy guy as the sheet, or have a "twinning line" or barber hauler to drag the sheet downwards, even as far as the deck. If you trim the clew downwards, you'd also want to trim the pole downwards.

There are loads of good dinghy and keelboat racing books, and lots on youtube, on sail trim; you don't need to be a racer to benefit from them.

 

[FairweatherDave]

Thanks for all that RJJ and for the other two replies. It's a balance between reading too much and getting enough practice to make sense of it all.....and remembering any of it after huge gaps in the time inbetween ?. But really helpful and certainly the full hoist to the top now makes complete sense. Bring on more practice!

 

[RJJ]

Post #3 is correct - you want the luff to curl evenly. If the luff curls at the bottom, pole up; if it curls at the top, pole down.

I don't know what idiot wrote that, but it's nonsense. Other way around. ;-)

 

[Concerto]

FairweatherDave you may enjoy watching this video I made. Concerto under spinnaker

I am singlehanded in this video so playing with spinnaker is not difficult, jusy have plenty of space to play.

The only extra advice I can give relates to dropping the spinnaker. Just before dropping, attach a snatch block on the sheet on the rail at the aft end of the coachroof to hold the leech behind the mainsail. Now trip the guy. Slowly drop the halyard (I leave just a turn round the winch for a little friction) and gather sail into the cockpit. Never got it wet using this method.

 

[TLouth7]

From previously posting on this subject I know the pole should be in line with the boom and I was able to just hold it off the furled genoa. After that I focused on keeping the sail up with the luff occasionally breaking at the shoulder, and keeping the two corners level.

Sounds like you got this pretty well spot on.

However what I have just been reading about is that the luff should be vertical from the end of the pole.....from the photos I took I can see the pole should have been even more forward (as stated not possible) because the luff was definitely leaning inside the pole.

The angle that the luff makes to vertical will depend on the cut of the sail, and potentially how stretched it has become. I wouldn't worry too much about it. I'm confused as to why you couldn't let the pole further forward? This would have the effect of moving the sail away from the forestay, not towards it.

A secondary question is the height of the top of the sail. I have no idea if the spinnaker is the right size for the boat, it may be a little small. Just trying to get the sail to look right I did not hoist completely to the top (maybe 3 or 4ft short). The pole was pretty much at the bottom of the track on the mast with the goal being to have it horizontal. Should I have hoisted all the way and set the height of the pole after that? Any guidance appreciated as always.....

Yes hoist to the top and then adjust the pole. That is why you have the track!

 

[flaming]

So in the good weather of last weekend with a gentle easterly approaching the Solent my wife was persuaded that I could hoist the spinnaker. Result! This involves me rooting around below for all the stuff required and then reading my notes on how to rig. In this department I am very much a newbie. Much to my joy we got the sail up without any problem behind the genoa. Now the challenge was to fly it for as long as possible and build experience. But we also needed to get through the submarine barrier and past Portsmouth and Gillicker, so holding a course was a perhaps a broad reach rather than a training run. From previously posting on this subject I know the pole should be in line with the boom and I was able to just hold it off the furled genoa. After that I focused on keeping the sail up with the luff occasionally breaking at the shoulder, and keeping the two corners level. However what I have just been reading about is that the luff should be vertical from the end of the pole.....from the photos I took I can see the pole should have been even more forward (as stated not possible) because the luff was definitely leaning inside the pole. Presumably the purists would say in that case I shouldn't have been flying the spinnaker? All I can say is it seemed to work pretty well.
A secondary question is the height of the top of the sail. I have no idea if the spinnaker is the right size for the boat, it may be a little small. Just trying to get the sail to look right I did not hoist completely to the top (maybe 3 or 4ft short). The pole was pretty much at the bottom of the track on the mast with the goal being to have it horizontal. Should I have hoisted all the way and set the height of the pole after that? Any guidance appreciated as always.....

Sounds like you're already getting the hang of it. A couple of pointers.

1. Definitely full hoist the sail. Allowing it to sway around can be an issue as the wind builds and the sail sways back and forth building up a rolling motion. There is also the issue that if the wind is spending energy moving the sail from side to side, then it isn't putting that energy into moving the boat. The same goes for tensioning pole down etc, if the pole is allowed to move up and down or back and forth by a slack pole down, then that's just energy that isn't being used to drive the boat forward.


2. If the sail is falling off to leeward too much and your pole is all the way forward, then try going pole down, that can have a similar effect.

3. When you have the pole on the forestay (i.e as far forward as you can get it) forget all that stuff about level clews and think of the sail as a genoa, you really want a nice tight luff and a nice twisted leach. If you try too hard to get clews level when sailing fairly tight angles you often end up with a sail that's doing too much pulling you over sideways and not enough pulling you forwards. Concerto's video is basically spot on at the point you see the pole forward, around the 3 minute mark, in terms of what you are looking for in the luff of the sail.

4. Don't get fixated by the "boom and pole making a continuous line" idea. It's a good guide, but it's not the be all and end all. Nor is the pole at 90 degrees to the wind. These are both excellent starting points for explaining the basic idea to newbies, but there are plenty of circumstances where this would not apply. For example when reaching in reasonably fresh conditions the pole will be as far forward as you can get it, but the boom will be quite eased. Similarly when running in fresher conditions you often hold the pole further forward, and further down, than the 90 degree rule would suggest, as this allows you to set the sail flatter and a bit hidden behind the main to limit the power, and most especially limit the windward heeling and leeward turning moment the sail can create.

5. As you get more experience you will undoubtedly find yourself in a position where you have the sail up and the wind has built without you really appreciating, and you're getting excited by the speeds you are getting surfing down waves etc... And then suddenly it's all a bit scary and you realise the sail is in charge, not you. The single most important thing to do at this point is to fight your instincts. DO NOT bear away onto a run. This is a sure fire route to a big wipeout when you're overpowered and under experienced. Instead gently head up to a true wind angle (TWA) of about 150. The sheet on the spinnaker quite hard and ease the pole forward (and down if you can). This will do 2 things. Firstly it flattens the sail and hides it a bit behind the main, but more importantly it ensures that the flow over the sail is only going from luff to leach. Most of the more spectacular spinnaker wipeouts result from an oscillating flow that is one minute going luff to leach, and the next leach to luff. Your next step is to deploy your genoa to blanket the sail and drop it.

 

[FairweatherDave]

Thanks for all the information and encouragement folks, particularly all that detail Flaming! ?
Enjoyed the video Concerto.....I have watched it before but it is more informative when I can compare it with recent experience. Gotta get ready for another weekend on the boat...maybe more spinnaker experience on Sunday?

 

[RJJ]

Sounds like you're already getting the hang of it. A couple of pointers.

1. Definitely full hoist the sail. Allowing it to sway around can be an issue as the wind builds and the sail sways back and forth building up a rolling motion. There is also the issue that if the wind is spending energy moving the sail from side to side, then it isn't putting that energy into moving the boat. The same goes for tensioning pole down etc, if the pole is allowed to move up and down or back and forth by a slack pole down, then that's just energy that isn't being used to drive the boat forward.


2. If the sail is falling off to leeward too much and your pole is all the way forward, then try going pole down, that can have a similar effect.

3. When you have the pole on the forestay (i.e as far forward as you can get it) forget all that stuff about level clews and think of the sail as a genoa, you really want a nice tight luff and a nice twisted leach. If you try too hard to get clews level when sailing fairly tight angles you often end up with a sail that's doing too much pulling you over sideways and not enough pulling you forwards. Concerto's video is basically spot on at the point you see the pole forward, around the 3 minute mark, in terms of what you are looking for in the luff of the sail.

4. Don't get fixated by the "boom and pole making a continuous line" idea. It's a good guide, but it's not the be all and end all. Nor is the pole at 90 degrees to the wind. These are both excellent starting points for explaining the basic idea to newbies, but there are plenty of circumstances where this would not apply. For example when reaching in reasonably fresh conditions the pole will be as far forward as you can get it, but the boom will be quite eased. Similarly when running in fresher conditions you often hold the pole further forward, and further down, than the 90 degree rule would suggest, as this allows you to set the sail flatter and a bit hidden behind the main to limit the power, and most especially limit the windward heeling and leeward turning moment the sail can create.

5. As you get more experience you will undoubtedly find yourself in a position where you have the sail up and the wind has built without you really appreciating, and you're getting excited by the speeds you are getting surfing down waves etc... And then suddenly it's all a bit scary and you realise the sail is in charge, not you. The single most important thing to do at this point is to fight your instincts. DO NOT bear away onto a run. This is a sure fire route to a big wipeout when you're overpowered and under experienced. Instead gently head up to a true wind angle (TWA) of about 150. The sheet on the spinnaker quite hard and ease the pole forward (and down if you can). This will do 2 things. Firstly it flattens the sail and hides it a bit behind the main, but more importantly it ensures that the flow over the sail is only going from luff to leach. Most of the more spectacular spinnaker wipeouts result from an oscillating flow that is one minute going luff to leach, and the next leach to luff. Your next step is to deploy your genoa to blanket the sail and drop it.

I'm reassured our advice is consistent ;-) keep learning and have fun,

 

[William_H]

With a very shy spinnaker depending on the cut of the spin you need to raise the pole end to reduce tension on the luff. tension on the luff tends to bring the camber forward to the luff which makes the spin luff and collapse. however in experience sailing with a shy spin is more about the helmsman than anything else. Sailing close to luff point wile being prepared to bare away if there is any over load of boat. (keep the boat under the spinnaker is the aim. Keep experimenting. ol'will