What exactly is mast "pumping" and mast tuning issues?

[rwthomas1]

Hello All,
Went out for a cruise this afternoon with the E38. Driving upwind/closehauled with 150% Genoa all the way out and full battened main in 16-17kts of wind. I went forward to check out the mast tuning and here is what I found:
Very slight leeward bend in mast on both tacks. Slight backward/forward motion of the mast at times, rhythmic motion, between fully straight and slightly bent aft.

I have checked the rig before and never noticed this. I was out for an informal race this weekend and it was blowing 25+kts. Had the big Genoa out and beat on the rig pretty hard before calling it quits after the first leg of the race. (Didn't think it was worth beating up my gear/boat) I am concerned that maybe I tweaked the shrouds?

So what do I tighten to straighten the rig? The cap shrouds? The lowers are fine, not loose at all on the lee side when sailing. The cap shrouds and the inners are both a little loose on the lee.

I am assuming the rhythmic motion in the mast is "pumping"? I tightened the backstay from 1700 to 2000lbs and the pumping appeard to go away. Then I noticed the Navtec hydraulic backstay adjuster was leaking oil from the piston/rod..... Great, another thing to fix!

Thanks, RT

 

[wurzner]

Sounds to me like you mast can "float" where it enters the deck. You need to make sure that it is securely supported all the way around. I' need to do the same with mine and will be using the mast collar system (spartight?) you pour around it and it creates a solid ring. A women in our area who is a race instructor had a hell of a time tuning her rig until she did this and boy, did it make a difference.

Good Luck
shaun

 

[escapade]

pumping aluminum

I have the spartite collar on my E34 and it does a nice job of positioning the spar. you will need to make sure it EXACTLY where you want it before you pour it though as it will hold the spar in that position. If you're getting pumping in the spar you need to tighten the lowers. You said you have a hyd. backstay (a good thing!) adjuster so you need to keep the aft lowers slightly looser than the forward lowers. You DO NOT want the mast to invert (have the outer arc of bend towards the stern) so by having the forward lowers tighter the mast will always bend correctly. If the mast inverts or the pumping gets out of control you'll make the boys at Rig-Rite VERY happy. They have new tube but it's not cheap. The uppers should be tight on the leeward side. I use a Loos tension gauge to make sure there about equal and it allows you to repeat tensions for conditions. (Less tension in light air, more in heavy air). I also use a 50' tape to measure from the masthead to the chainplates to keep the spar centered over the boat. Hope this helps.
Have fun & sail fast
Bud E34 "Escapade"

 

[Seth]

Doubt it is the partners

OK..
1). The "fall off" (not sag or bend) to leeward you are seeing is due to either the caps being a bit too loose, or the lowers/intermediates a bit too tight.
I am assuming you saw this fall off in the top section of the mast. If this is true, and from what you describe, I would tighten the cap shrounds a turn or 2-leaving the others alone. Do this evenly side to side until the top no loger falls off (we are assuming the mast is centered in the boat-top to bottom).

2). The pumping (correct term here) you see is a natural result of the boat motion in waves-and a very small amount is OK (maybe 2" max). But if it is more than this, I would tighten the for and aft lowers a bit more to reduce this (but remember the relationship to the caps-the caps will need relauvely more tension than the lowers to eliminate thhe tip fall off).

To truly eliminate pumping, a babystay and/or runners will solve this, but unless you are going offshore for any length of time, I would not worry about adding either of these.

Finally, some of the problem is you are sailing the boat with WAY too much sail for the conditions-and this will definitely exaggerate what you have observed.

A full main and fully open 150 is too much to upwind with in 17 True WS-never mind 25 knots!!! Even with a full gang of rail sitters, at 17 True(upwind) you should have a bladed out(flat) mainsail and a headsail no bigger than 130%, and in 25, a 100-110% headsail is even better....With this much sail, you are heeled over too far (which is slow and creates excessive leeway and helm) certainly not comfy..

Boats in general perform better the more level they are, and certainly 15-17 degrees of heel is a close guess to the point where you bare giving up performance due to too much heel.

Best,
S

 

[rwthomas1]

Thanks for the great input. I will try putting a turn or two in the capshrouds and see if it takes the lee bend out. This is a learning process on a new boat. I thought the 150 was a 130 and so was wondering why I have had problems with what I feel was excessive heel and weather helm. Speaking with a sailmaker he felt that the Doyle sails I have are too lightly built at about 6oz material and already a bit blown out. Recommending a heavier and smaller 130 Genoa for the sailing I normally do. Anyway, I'll work the bugs out eventually. Thanks, RT

 

[Seth]

All good

RT,

First, lets clear up the terminology:

1). "Bend" is the deliberate shaping of the mast (fore and aft) to control mainsail draft.

2). "Fall off" is what you are seeing at the top of the mast, and is athwartships displacement of a section of the mast (top or middle) due to improper mast tune. One exception is that some One Design classes will tune specifically to produce a small amount of tip fall-off for heavy air-but this would not apply to your boat.

3). "Pumping" (described in my last post) is the fore and aft movement of the mast as the boat sails through the water. This will increase with both windspeed and wave height. Some of this is normal, but it can reach a point where it must be controlled or limited, as excessive pumping can fatigue many parts of the rig. If the normal standing rigging is not enough, items like running backstays, baby stays, or an inner forestay will help reduce excessive pumping. For coastal sailing on the E-boats, you should be able to keep it under control with the standard standing rigging..

4). "Rake" is the orientation of the mashead forward or aft of perpendicular to the waterline. 4" of aft rake means the masthead is 4" AFT of a point extending from the mast step and going straight up, keeping this line at a right angle to the waterline. Rake position affects balance, and as a result weather or lee helm, since when we adjust Rake, we move the Center of Effort of the sailplan either forward or aft of the CG in the keel. If you rake aft, and place the CE behind the CG, the boat will want to head up towards the wind (think of a weathervane), or if it is fwd off the CG, you can induce lee helm (again, weathervane backwards). The goal is to set the rake to produce a small amount of weather helm in light-medium air; just enough to make the boat "want" to point higher. Too much aft rake and the boat will have too much helm (and hence rudder drag) when the breeze is up, and will not balance well on a reach. Usually this is between 0-3-4" of aft rake-depending on the boat. Light air regions will want slightly more aft rake, the SF Bay will need less. Many confuse Rake with Bend, and they are quite diffferent. Bend is or can be frequently adjusted and controls SAIL SHAPE. Rake is usually set for the season, and controls BALANCE..

Sailcloth weights: I am not sure what you are being told. 6 oz (dacron) is PLENTY heavy for a 150% genoa on E-38. It is actually a bit on the heavy side since the boat will be overpowered well before the fabric is being stressed, and if you build itr just a tad lighter, it will perform better in the conditions where the boat can take full advanage of the extra sail area (up to about 12 knots True for upwind sailing).

A 130, which may well be a better choice for you for your primary sail could be anywhere from 6 to 7.55 or 7.65 oz-there are a lot of choices now in this weight range. For sure a normal cruising 6 oz cloth would be slightly on the light side, but a good 6.6 woud be fine, and 7.25-7.55 probably ideal, especially when durability is a big concern.

I just wanted to be clear-if he says 6 oz is too light for a 150 he may not understand the boat...Email me off line and tell me the name of the guy you are working with-I may know him.

Happy sailing,

S

 

[rwthomas1]

Hello Seth,
Thanks for the explanation of the terms, I did know the meanings however I don't know exactly what adjustments fixed each condition. Rake is unknown, and I am making the assumption that the rig is centered as it was setup by pros supposedly under sail.

I will be adjusting the capshrouds and lowers to remedy the fall-off and the pumping. The pumping was not maybe more than an inch. I don't know why but tightening the backstay seemed to aleviate the pumping at the time I did it. Will have to check more carefully.

Regarding the new sail. The sailmaker for the local Haarstick loft was a bit down on Doyle. Not that he seemed enthusiastic about downplaying Doyle, more like if you spent the money you should have gotten more? The material on my current sails, according to him, is at best a 6oz and better suited to one-design sails on smaller boats. The cloth has a crosshatch pattern that sorta looks like graph paper you used to use in math class. Again, according to him, Doyle likes to use this stuff but not many others do. It holds its shape fairly well for a season or two and then quickly stretches out too far. I am inclined to believe him as the genoa has a fairly deep draft and I cannot get it flat in any way. This may be normal for a 150, I don't know. The Haarstick sailmaker is recommending for a dacron crosscut 130 an 8.3oz material. For the triradial laminate I have no idea on the material weight. Maybe my specifications slanted the material choice? I want maximum life/shape out of the sail. The local Haarstick guy is Jeff Gibbs at the Wickford, RI loft. He stated he had been making sails since 1983.

Let me know what you think, RT

 

[Seth]

No problem

The 1 inch of pumping is within reason, but even so, it would be normal for an addition of backstay tension to reduce the pumping-so all sounds right on this point.

Regarding Jeff's ideas: Haarstick is a singularly capable "smaller" loft with a long history of smart innovations, so I would not argue too much with them. It certainly IS possible that his fabric choice was biased by your requirements.

I would only say that while the 8.3 is very good cruising cloth, this is a fairly tender boat, and sensitive to weight aloft. We made many very durable 130% gennys with 7.3, 7.55, and 7.6 dacrons. That is what I would do-BUT there is no real harm in stepping it up an ounce in body weight, and an argument could be made that the corner patches will not need to be as heavy-which could offset some of the weight gain. The sail WILL last, and if that is what he is comfy with, fine. No harm done. The laminate tri-radial option should be quite a bit lighter. You can share this with Jeff if you like, or just go with it.

The only thing I would take any issue with is the notion that Doyle routinely used inferior cloth that did not hold up-we never did this while I was with Doyle-but it really does not matter-Team "H" makes great sails, and I think you will be very happy.

Good luck!

S

 

[rwthomas1]

Seth,
Thanks for your input. I had no idea you were with Doyle so that certainly makes your thoughts appreciated. Regarding the Doyle comments, the material was not stated to be "inferior" in any way, just that he felt that it was inappropriate for the intended use. I suppose this is somewhat subject to opinion and what you want to do with the sails. I have no idea what the PO wanted to do with the sails and I suppose it is possible that he chose sails due to price as he was thinking of selling the boat in the near future?

Regarding the cloth choice, I have no idea what is or is not appropriate. I do know that the cloth on my 150 seems quite a bit lighter than other genoas on other boats I have handled. The commentary from Jeff was that a stiffer, flatter sail will provide more drive and less heeling than a deeper draft sail. I am completely ignorant on these points so if this is wrong then please educate me..... What I have heard so far makes sense.

Narragansett Bay offers light morning breezes of 7-10 knots, usually out of the North. Right around noon every day the wind shifts to a southerly and picks up to 15-16 knots, getting progressively stronger to average 20kts in the mid afternoon. Often it blows harder.

Given these conditions the stiff 130 makes sense to me as it has been explained. We do have summer "dead days" with 5kts or less and these obviously would be better served with the 150. Ah, decisions decisions.

Your input is appreciated. RT

 

[Seth]

Seth,
Thanks for your input. I had no idea you were with Doyle so that certainly makes your thoughts appreciated. Regarding the Doyle comments, the material was not stated to be "inferior" in any way, just that he felt that it was inappropriate for the intended use. I suppose this is somewhat subject to opinion and what you want to do with the sails. I have no idea what the PO wanted to do with the sails and I suppose it is possible that he chose sails due to price as he was thinking of selling the boat in the near future?

Gotcha-yes, this is very much a matter of opinion and specific needs of the client-no harm done

Regarding the cloth choice, I have no idea what is or is not appropriate. I do know that the cloth on my 150 seems quite a bit lighter than other genoas on other boats I have handled. The commentary from Jeff was that a stiffer, flatter sail will provide more drive and less heeling than a deeper draft sail. I am completely ignorant on these points so if this is wrong then please educate me..... What I have heard so far makes sense.

A 150 is considered a light air sail, and should have lighter cloth than a smaller sail intended for more wind. Jeff is correct in saying a flatter sail will create less heeling and hence more forward thrust than a deep sail-especially in the winds where a 130 is the better choice-which for your boat is about 12 knots and up.-Not sure what he means by "stiffer", other than meaning low stretch, and this should be intuitive, but again, you can get these characteristics with many fabrics....The bottom line is that Jeff has not said anything at all wrong, and I am comfortable with his guidance-the ONLY thing I would want to make sure he is aware of is that your boat is on the tender side for cruisers, and will not carry big sails in as much wind as a Pearson, or other cruising yachts. It is possible he is making his recommendation without knowing this, and many of those heavier, stiffer boats would make better use of heavier fabrics. But..if he is aware of this, and it is what he is comfortable with, fine-the difference is small enough to be almost splitting hairs...NO worries!

Narragansett Bay offers light morning breezes of 7-10 knots, usually out of the North. Right around noon every day the wind shifts to a southerly and picks up to 15-16 knots, getting progressively stronger to average 20kts in the mid afternoon. Often it blows harder.

Given these conditions the stiff 130 makes sense to me as it has been explained. We do have summer "dead days" with 5kts or less and these obviously would be better served with the 150. Ah, decisions decisions.

Frankly, you may want to consider something even smaller. At 20 knots going upwind, the 130 is too much sail-unless you have a gang of crew on the rail.

I grew up sailing on Buzzards Bay, so I "get it"...
My choice would be something like a 110-115% genny on the furler, and an Assymetric cruising spinnaker in a sock or snuffer..and that is all you need..

In the mornings, you can sail much faster with the A-sail than you could even with a 150-at all angles except very close hauled (and who wants to sail close hauled in 5-7 knots?). They are very easy to handle in lighter breezes, and will give better performance when on a broad reach than any of the genoas. No other sails need be carried for normal sailing.

If you are cruising with just the family, by the time you have 15 knots True, you will indeed be more more comfy with a 115 or so than you would with a 130, and this will be more evident as the wind builds.

From your posts it sounds as though you have spent a lot of time overpowered, over on your ear, and I think you and your family will enjoy more speed, better pointing, and a more secure feeling with te smaller sails.

You can call me to chat if you feel like it-I think you have my cell #.

 

[rwthomas1]

Thank you Seth,
I will be speaking to the sailmaker about your concerns and specifically mention the "tenderness" you speak of.

I think maybe my E38 is not as tender as most as it has the added on Mars Metal keel bulbs. IMHO, she carries the 150 very well until about 16kts which is far enough above your stated range of use that I'm thinking the extra ballast is responsible. I am able to trim with the traveller for maybe 1/8th of a turn on the wheel to counter the weather helm which is pretty much the least amount of input needed on this boat in any breeze.

The boat came with a spinnaker called an Ulman "flasher" IIRC. It looks very lightly used. No idea what it is. I have no idea how to even set, trim or douse a spinnaker. I suppose if this is the asymetric you are refering to I need to learn how to use it.

How do you feel about laminate genoas? That would be the next decision...

Thanks, RT

 

[Chris Miller]

cruising chute...

Hey Rob,
Lots of discussion here about cruising chutes if you search on it. also, here's a link to the UK website about how this stuff works. we have one of their "flashers", I think Seth did a nice discussion about how they are cut and etc...
http://www.ukhalsey.com/LearningCenter/encyclopedia/encyclopedia4e.asp
chris

 

[Jeff Meier]

Sounds to me like you mast can "float" where it enters the deck. You need to make sure that it is securely supported all the way around.

I just noticed that my 32-3 is like this. apparently there are no shims or anything holding the mast in position at the deck. I can actually see the mast moving from inside the cabin when the boat is moving around. i've also noticed some mast pumping as defined above.

i have a loos guage and will check the tension on the stays but how do i secure the mast at the deck? just use some wooden shims and tap them in place all around the mast? and should i be worried about damage that may have occured from how it has been??

i appreciate any help with this.

Jeff

 

[Seth]

Moving in the partners

It is definitely a good idea to secure the mast in the partners (deck cutout). Wooden shims are fine, and there is a product called "Spartight", which can be applied-after which it will hardenand form a watertight seal in the deck cutout. This may be the best way to go for you. I doubt you have done any harm so far, but you will have better control of the spar, and hence performance with the mast secured.

Cheers,
S