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Polars for E32-3

RHenegar

Member I
Does anyone know if Ericson published polar diagrams for their boats? What I am specifically interested in is finding polars for my E-32-3 with 4'4" draft.

Rick Henegar
S/V Skimmer
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Question has come up over the years. As far as I know, nobody has one even if some once existed.

Useful polars are (very) hard to produce, but here's some information from another thread:

Seth
02-06-2014, 09:54 AM​

While my response won't address your question directly, it may be close enough. There is an app on iTunes (https://itunes.apple.com/us/app/ipolar/id577106473?mt=8) that allows you to calculate your boat's polars. The price is about $11.

I checked this out, and while it sounds nice, I have trouble seeing how it could be accurate based on the following being the available inputs:
Length Overall
- Displacement
- Mainsail area
- Jib area

(units can be set to metric or imperial)

Optional data:

- Length Waterline
- Symmetrical Spinnaker area
- Assymetrical spinnaker area

Without the waterline number it would be really bad, but even with it, there are no entries for hull shape, and the B/DISPL ratio is really important, as are so many other variables. If you enter you jib area as a 105% for example, the polars are all wrong for the 150%, 130%, etc.. I do see it is interactive and can learn, and maybe over time could be more useful, but right off the bat it is not going to give very good data. Cute, though.....

Guy Stevens
02-06-2014, 01:15 PM​

http://www.techsail.com/sailfish/

Guy
 

bgary

Advanced Beginner
Blogs Author
Seth: I have trouble seeing how it could be accurate based on the following being the available inputs:
Length Overall
- Displacement
- Mainsail area
- Jib area

FWIW, I agree. That's not nearly enough info to generate a meaningful set of polars.

As a quick example, take a look at the E32-III, the Aloha-32 and the C&C 3/4T on sailboatdata.com All of them are ~32.5' LOA, ~9800# displacement and ~500 sq-ft sail area.

No *way* they have the same performance curves.

In order to get good polars, the calcs would have to consider draft, righting moment, shape... a bunch of things.


$.02
Bruce
 

oldfauser

Member III
Ericso 32-3 spped

Does anyone know if Ericson published polar diagrams for their boats? What I am specifically interested in is finding polars for my E-32-3 with 4'4" draft.

Rick Henegar
S/V Skimmer

We have learned a few things about the boat, with the 4'4" non-wing keel. One: keep the heel under 20 degrees; two: try to keep less than two spokes of weather helm in the wheel... closer to one spoke is even better. Change the trim (or traveler) if more!!!!

the boat is actually very fast.

Polars are good starting points, but learning the "feel" of the boat is even better :egrin:
 

p.gazibara

Member III
Polars are specific to your sails. Every sail is going to give you different performance in different windspeeds and directions.

It's pretty easy to build them yourself if you can record how you boat does on different points of sail with different combos up.

We did a little bit of it before Swiftsure last year on Cinderella. It was really interesting to learn that reducing headsail early lead to a faster boat as the wind built. She likes a full main over a full jib.

But again it's all sail specific.

-P
 

bgary

Advanced Beginner
Blogs Author
It's pretty easy to build them yourself if you can record how you boat does on different points of sail with different combos up.

Great point. I had been thinking in terms of calculating polars based on the design, but it's quite possible to build a set by recording performance over time.

There are some instrument systems that do pretty robust data-logging. Can record boat-speed, wind-speed, apparent wind angle and a variety of other things on a very granular basis, resulting in a datafile that you can download and analyze. Or, old-skoool way is to keep a notebook, and record windspeed, boatspeed, wind angle, sail combination(s) and other interesting tidbits (like lead positions or traveler position, sea-state, etc.). Over time, you'll end up with a bunch of data and can plot it on a polar diagram.

The thing with doing it that way, though, is that (Bruce's Opinion) you end up with a record of the best your boat has ever done, which may or may not be the same as the target/best the boat is capable of.

$.02
Bruce
 

e38 owner

Member III
Sailgrib as well as some other programs have quite a bit of Polar data.
You can get a fair starting point using a few of these
Iregatta will keep track of your data if you manually enter wind speed and direction or if you connect to your instruments via 0183 wifi
Sailgrib has a decent selection of boats. As you analyze the data you will notice that for similar boats the base graph is similar.
You can probably find boats that are similar and adjust accordingly.
From that you can create a rough set of upwind and downwind target boat speeds
On this website there is a rough set of polars for an E38 with a 130 headsail from us sailing.
From those you can start getting some baselines because the hulls are the same The angles should be close
Examples
you could adjust the 38 by difference in phrf rating converted to secs per mile
You could adjust the 38 based upon hull speed
You could then compare those charts to boats found in SailGrip or blue water sailing
Boats that may be similar are a J30
Catalina 36 -34
First 31
Grand Sooel 34
http://l-36.com/polar_polars.php
Compare those to your sailing experience and you can generate some targets.

I have played with targets quite a bit and found that they are interesting and can be useful in planning a course.
When planning a course I have found if I pick a polar that should be slightly slower than my boat I get good results
I have also found that my instruments are not and cannot be calibrated to really use the info for the following reasons
Wind Shear makes downwind wind speeds low and my instruments cannot handle a table
Boat Speed. I have only one knot meter a little off center. Boat speeds are different from tack to tack.
I generally in sail light wind thus small difference make big differences in information
You can check you instruments by tacking upwind. If the boat is tuned right and the instruments are correct the TWA &TWS should be constant
Overall My favorite movie line applies to polars in my situation regarding the pirates code
"They are really more like guidelines"
 

RHenegar

Member I
Tacking angles

What I am really concerned with is tacking angles. Based on GPS plots, this boat tacks between 115 to 120 degrees COG with AWA between 40 and 45 degrees If I push higher than 40 degrees the boat really slows down and seem to sail best at 45 degrees AWA close hauled. Sail are old but appear to have good shape. I am trying to get an honest assessment of how the boat is performing against the design standard or against others experience. If others are able to consistently sail angle better than 115 degrees in a shoal draft e32, then I need to be looking at sails. Of course the problem could always be the hands on the wheel.

Rick Henegar
S/V Skimmer E32-3
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
You can happily discount any claims made by anybody anywhere about how close or fast their boat sails to windward, or any other tack for that matter.

Just consider it conversation. There is too much data needed for any meaningful comparison or claim.

The only way to see how your boat performs versus another 32-3 is to sail side by side. The next best test is racing, which will give you performance against similar boats, uncorrected for almost everything.

With old sails, it takes a trained eye to know what the camber should be, and to recognize that the center of effort has moved. When the wind comes up the tired cloth of an old sail is unable to keep its shape. It's subtle, but it makes all the difference in the world. The more wind, the worse old sails bag out.

However, the effect is relative to your standard of enjoyment. Old sails may be fine for cruising.

A sailmaker will tell you that an old sail is 5 years old. Much less than that for racing.

Yeah, but. Are we racing?

You know those $10,000 mainsails you see going by, the ones with different colors and complicated stitch and layer patterns? That's all about manufacturing a piece of cloth that can hold a specific shape in different wind and sea conditions. It's a design and materials challenge. Cruising sails can't compete with that. But that is the key to going to windward fast and not just being blown on your side to wallow, which is what a bagged out old mast awning does.

We all need new sails. It's the first thing everybody who enters a Wednesday-night beer can race buys after all the other boats go by. Then they hire a racing pro as crew, to give them tips. Then they buy a new boat that's actually fast, with comfort compromised. Then they fret about their handicap, send spies to examine competitors, and get in a big beef about remeasurements. And then they kick their friends off and seduce (with money, or jobs, or plane tickets) a highly experienced crew, than then they buy a new boat again, and then they win some races, and than they enter the worlds and come in 28th.

How fast should my boat go?

Fast enough so you feel good about it. New sails always help.
 

oldfauser

Member III
we all can use new sails...

What I am really concerned with is tacking angles. Based on GPS plots, this boat tacks between 115 to 120 degrees COG with AWA between 40 and 45 degrees If I push higher than 40 degrees the boat really slows down and seem to sail best at 45 degrees AWA close hauled. Sail are old but appear to have good shape. I am trying to get an honest assessment of how the boat is performing against the design standard or against others experience. If others are able to consistently sail angle better than 115 degrees in a shoal draft e32, then I need to be looking at sails. Of course the problem could always be the hands on the wheel.

Rick Henegar
S/V Skimmer E32-3

We had to replace our 155 jib this last year as the old one was falling apart! (we had "air vents" where we should not have them!) It did look "OK" up until then.

It was amazing how much better the boat performed with the new jib.

so as it has been said... we all can use new sails!
 

e38 owner

Member III
I happen to agree with Christian and it is all relative to your purpose.

Our boat, a 38, with a nice kevlar 155 and a not so nice dacron 135. will tack through about 100 degrees
Both sails are cut for racing and that makes a difference. Deck sweeper, Low Clew, No roller furling cover.
A high clewed roller furling sail I find to hard to control the leech, foot and block position to get a great shape
That being said another boat out with you really helps.

Using a compass is good if the wind is steady to determine your tacking angle. If you use GPS COG the angle would most likely be greater because a gps would take into account leeway which is not included in a polar, compass heading or wind instruments. I bought a used TickTack. They are great. It is so much easier for me to remember a digital readout to see a header and lift as opposed to a compass card.

When sailing to windward. Center the boom. Adjust mainsheet so top telltale does not quite stall
Adjust Jib sheet tension based upon tape marks on the spreader. Never touching. if there is wind probably never greater than 12"
Check halyard tension, draft and backstay. If the boat is hard to keep in the groove, I have have often found that the back stay is too tight
If groove is huge but can't point tighten a bit

Once you feel you have a good setup tack and try to repeat. That should give you a good angle.

As you point higher speed can really drop off. using vmg to windward can help if you hold a steady course and don't try to fool it. The boat has to settle in. Wind and sea have a lot to do with angles. Flat water, steady breeze is completely different than rough water and variable breeze. sailing fast is not always the fastest and point to high is not always best. The key is to find the spot that works. Other similar boats help with that.
 
Last edited:

bgary

Advanced Beginner
Blogs Author
When sailing to windward. Center the boom. Adjust mainsheet so top telltale does not quite stall
Adjust Jib sheet tension based upon tape marks on the spreader. Never touching. if there is wind probably never greater than 12"
Check halyard tension, draft and backstay. If the boat is hard to keep in the groove, I have have often found that the back stay is too tight
If groove is huge but can't point tighten a bit

^^^this is a good primer on how to start "working up" a boat.

I'd add, you can use the "speed made good" function on most GPS units to help build a baseline for VMG. Basically, project a waypoint some distance (a couple of miles) dead upwind of you, and then set the GPS to display "speed made good" - that'll give you an indicator of how fast you're going toward that upwind mark (aka VMG).

To really make this work you need a steady (not shifty, not puffy) breeze, and no cross-course current. But this can help you build a baseline for your angles and target speeds, and then you can play with variables to see how steering (pinching or footing) and sail trim affect your VMG
 

RHenegar

Member I
Great information all, thanks. @e38 owner, you mentioned that COG angles would be wider because they would include leeway. It seems to me that leeway would be a natural part of predicted sail angles as long as it is not being induced by currents. I would think that my boat naturally makes more leeway close hauled then on a beam reach.
 

Bolo

Contributing Partner
Feel the groove!

We have learned a few things about the boat, with the 4'4" non-wing keel. One: keep the heel under 20 degrees; two: try to keep less than two spokes of weather helm in the wheel... closer to one spoke is even better. Change the trim (or traveler) if more!!!!

the boat is actually very fast.

Polars are good starting points, but learning the "feel" of the boat is even better :egrin:

I agree with your assessment of the 32-3 because I own one on the Chesapeake Bay. I don't race but I do cruise but I'M always interested in "tweeting" the boat to get the best speed. Polars are good to know I suppose but sometimes I think that relying on too much info can be detrimental too. I've read that it sometimes even happens with fighter jet pilots. If you've been sailing a particular boat for awhile (I've owned our 32-3 for more then 10 years now) you can "feel" when things are right. I can even tell by the sound of the water behind the stern that things are going well. I can best describe it as a "happy gurgling" sound. Very unscientific but I think you may know what I mean. My 4'-4" keel has never been an issue for me on the bay and in fact its more of an advantage. I can cross shallows that other full keel boats can't and shave a lot of time off my journey. Of course knowing what shallows to cross and when are important, otherwise you'll get stuck in that Chesapeake mud. I never have, of course. If you believe that one I then I can sell you one of the Chesapeake Bay bridges....or both if you have the cash!
 

RHenegar

Member I
Bob, The bays in Texas are shallow just like the Chesapeake and there are two types of sailors in Texas. Those that have run aground and those that don't leave the dock.

Rick Henegar
s/v Skimmer
 

Bolo

Contributing Partner
Bob, The bays in Texas are shallow just like the Chesapeake and there are two types of sailors in Texas. Those that have run aground and those that don't leave the dock.

Rick Henegar
s/v Skimmer

So you’re saying that I’d be right at home sailing off of Texas? Luckily I can only think of one natural rock (besides the rip rock along some of the shore lines) that sticks out of the the water in the bay that can sink your boat. It’s near the entrance to the Sassafras River in the northern part of the bay but it’s well marked. I’ve done my share of hanging my behind off the rail to tilt the boat with the engine running to get myself out of the mud.
 

gadangit

Member III
What I am really concerned with is tacking angles. Based on GPS plots, this boat tacks between 115 to 120 degrees COG with AWA between 40 and 45 degrees If I push higher than 40 degrees the boat really slows down and seem to sail best at 45 degrees AWA close hauled. Sail are old but appear to have good shape. I am trying to get an honest assessment of how the boat is performing against the design standard or against others experience. If others are able to consistently sail angle better than 115 degrees in a shoal draft e32, then I need to be looking at sails. Of course the problem could always be the hands on the wheel.

Rick Henegar
S/V Skimmer E32-3

Hi Rick-
I'll bet I could enlist a couple young guns that work in the local sail loft to join you on your boat to wring out what they can. I'd even come along if invited... :)
Are you planning on doing the Icicle series?
Chris
 
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