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Bob Perry's take on Wolfenzee's dream boat

187K views 1K replies 48 participants last post by  Rhapsody-NS27 
#1 · (Edited)
In the "Modern Hull forms and Motion Comfort" thread,

Post # 142, Wolfenzee said to Bob Perry " BOB: take a close look at the lines of my boat and tell me could a fin keel have been designed in relatively easily http://atkinboatplans.com/Sail/images/CaptainCicero-3.gif
[/I]"

And in Post #152 and #153 Bob Perry Responded:
(#152)"Damn it Wolfer!
You made me think.
I hate it when that happens.

Sure I could do your boat with a fin keel and a nice skeg hung rudder or better yet a spade rudder.

It would look just like your boat....above the water. Under the water you would not recognize it. I would have to shave away all that deadrise and reduce displ while carving away some volume forward and reducing some hollows aft.

But in the end you and me would love it. It would be a WOLF in sheep's clothing like NIGHT RUNNER."


(#153) "Wolfy:
Next Wednesday post your hull lines again and a photo or two of your boat.
When I start thinking about a new boat I need to see it and I think it would be fun for all of us to see what your boat would look like with a more modern hull combined with that traditional Atkin look.

I have to do this to get it off my mind. I'm built like that.

Or, Jeff could do it. I know he could.
Or, Jeff and I could do it together.
He'd do the hard work and I'd do the pointing and gesturing.

Either way let's see if we can produce a boat that will get your juices flowing."


And I am bowled over by that.

As a SailNet Moderator, I can only thank Bob Perry for that generous offer to come up with a design that explores Wolf's question. That is a true gift to this forum. Normal folk rarely get to see a custom design process and so this should prove interesting.

And I am truly honored that you would be willing to do this with me. I truly appreciate Bob's willingness to give that a try.

This is a thread for that process. I am excited to see where this ends up....

Jeff
 
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#374 · (Edited)
the solutions presentled to me for of my problems often are preceeded with "Why don't you just buy....." example, the new mainsail mentioned is 20-25% my annual income (and of course I would have to get a full suit of sails to match), the fix for the drag from my 16x9 three bladed prop is even more, an asymmetrical spinnaker is close, because my cockpit isn't bristling with techno gadgets and gizmos it was suggested I spend $5000 before I think about going anywhere, someone else insisted I needed a $4000 20gph watermaker.......
the words NEED & WANT are often confused....if we wait till we get everything we want that we think we need.....we will never leave the dock.....If you sit down and figure what you actually need, then add what you can to that you can sail away. I believe it was the Pardey's that said "Go simple go now".....I am not saying go so bare bones you are uncomfortable, I am just saying take a look at what is really necessary.
 
#392 ·
That is what kills so many cruising dreams, people being conned in to buying what the Ship swindlers tell them the absolutely need, which they would often be better off without . I met a couple who sailed from BC to Cape Horn and back with stuff still in the box, which they were told they would absolutely need.
I hear designers and builders are having a hard time lately, mostly those who design and build on the theory that their clients have endless supplies of money. How much faith can one put in the math skills of those who fail to realize that the 99% is a much bigger market than the 1%?
I have been turning away more work lately than I want do.
 
#376 · (Edited)
Wolf:

I would agree with you that most of what has been discussed falls heavily into the category of 'wants' not 'needs'. You and I would probably agree that the only true 'needs' are food, water, air, and shelter from extreme conditions. Anything else is a 'want'.

Many of these suggestions would be improvements to the way your boat would sail. So some of of the participants in this thread would want these things if this were our boat, and so consequently have suggested these items thinking that you may wish to think about adding them at some point.

My comments on your mainsail result from me interpreting your post #317 as you saying that you want a new mainsail and are saving to buy one. My comments are only aimed at making sure that you understand what you are buying, and because your comments show that you have no clue about the realities of what you are saying.

First of all, actually measuring Atkin's drawings, it appears that Atkins has drawn the boom almost 20 feet long. That means that your boom is approximately five feet shorter than the original design. If your boat balances so well now, that means that Atkins really blew it badly. That would move the center of effort of the mainsail roughly 3'-4" forward of its original designed position. That is enormous. We normally think of a changing rake and inch or two as a big correction. Then when you add the increased jib luffs, that moves the center of effort even further forward.

As to the mainsail you seemed to mention wanting, while you did not mention the words 'hollow leech", the reality is that any reputable sail maker would not try to build a battenless mainsail without a hollow leech. A straight battenless leech would beat itself to death very quickly and would need a large leech cup to minimize that. The typical accepted recommendation for leech hollow on a battenless main falls between 2% and 5% of the leech length depending on the intended use of the sail, and its construction. 2% is 10" and 5% is roughly 2 feet.

If you sail maker has not explained that to you, then you really need a new sailmaker because no competent sailmaker would recommend a batten-less mainsail without explaining the buyer the generally accepted realities, i.e. that they have a shorter lifespan than a fully battened mainsail, that they have a hollow leech, and that therefore they have way less area.

Measuring the actual drawings, with a 15 foot boom, you could easily have as much as 18" to 20" of roach on your sail. That means that minimally, you are losing close to 50 feet of sail area. That is huge.

Respectfully,
Jeff
 
#377 · (Edited)
More complete lines and sail plan

So 'My Version' has been progressing nicely. Since the last post the efforts have been aimed at refining the hull shape and rig a little...smallish tweaks, lots of lunch hours. Here is where the design stands as we move into the long weekend....







The numbers are:
LOA 39'-11.5"
LWL 35'-6"
Beam 11'-9.75"
Draft Min. 5'-0"
Max 7'-6"
Displacement 14,475 Lbs.
Ballast 5,500 Lbs.
Sail Area Main 479 S.F.
100% fore 355 S.F.
Total 834 S.F.

D/L 144
L/B 3.01
SA/D 22.54
Prismatic Coef. 0.530156
LCB 55.68%

The next step is to start to lay out an interior.

Have a great weekend,
Jeff
 
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#379 ·
I personally don't like sail drives. They are an example of a low maintenance but disposable technology. Even though they are a lower drag than a conventional shaft and strut, the deal buster is the proprietary folding props and annual maintenance on sail drives require a haul out.
 
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#381 · (Edited)
I did not loose sail area (according to the second owner he shortened the foot by 3' and raised the tack by 18", foot is now 15' and luff a tad over 37'), it was merely relocated to forward of the mast. One of my new headsail configurations consists of a Genny (25'luff, 15'foot, clew a little high, head 12' from masthead) on the headstay and Yankee (35'luff on 5' pennant, clew 20' off the deck, head 1' from masthead) on the topmast stay...they set very nicely together. $100 for used sails+$140 for pair of used Barient 25 two speed winches+misc hardware and work making new winch mounts total cost about $250, not including new standing rigging 1/4" 316SS $250, new halyards 230' 7/16 Endura $140. If those costs don't seem to add up I got the wire through a commercial source and paid spool price of 75cents/ft and have a contact who sells New England Rope so can get "end of spool" pieces for about 60cents/ft also have a contact for SS hardware.
The original rig had a nasty weather helm...the only purpose behind it I can figure was you only had to own two sails, a really big main (which in anything but a light air was overpowering the boat anyway, probably why it had a triple reef)and a fractional self tending jib (which according to the owner that removed it "tracked very poorly"). The present rig which allows for a masthead jib and/or a cutter rig which more than makes up for the lost sail area. It will be quite a while before I can afford a new main so I will put alot of thought into what I get and be open to suggestions.
The original rig was not designed for performance, rather simplicity (not spreaders, no fixed backstay, no cap shrouds, fractional with no jumper struts, no winches) and to be single. handed. Atkin even said of it "This is not a racing machine". Second owner had a bit more sense about performance, while still keeping the boat easy to single hand.
I am a poor cursing sailor and am trying to do as much as I can with what I have.
Bob: I don't think my boat is perfect, just less imperfect than some people suggest.
 
#382 ·
I did not think that your boat had necessarily lost sail area, when it when the boom was cut down and a second headsail added. But what did happen is that the center or the sail plan moved 3-4 feet forward of where it was designed. If the boat is balanced now, this suggests that Atkins got it wildly wrong in his original design. Going battenless, will require a hollow leech and that well decrease the sail area by roughly 45-60 square feet as compared to a sail with a reasonably normal amount of roach. It will also move the dynamic center of effort forward some more potentially damaging the balance that you currently have.

That was all that I was saying,
Jeff
 
#383 · (Edited)
I did not think that your boat had necessarily lost sail area, when it when the boom was cut down and a second headsail added. But what did happen is that the center or the sail plan moved 3-4 feet forward of where it was designed. If the boat is balanced now, this suggests that Atkins got it wildly wrong in his original design. Going battenless, will require a hollow leech and that well decrease the sail area by roughly 45-60 square feet as compared to a sail with a reasonably normal amount of roach. It will also move the dynamic center of effort forward some more potentially damaging the balance that you currently have.

That was all that I was saying,
Jeff
The mainsail was changed in 1982, and the boat has been sailing happily with this sailplan for about 30 years. Though I might take into consideration different methods of sail manufacture I am not suggesting any major changes (the sail I have is battenless and I was simply looking as a direct replacement for what I have...with maybe a few tweeks) to the mainsail other than maybe paying closer attention to the camber of the mast.
The changes I have implemented will not impact the center of effort to a degree to have a negative effect. example: the Yankee has a 35' luff and is flown on a 40' stay w/a 5' pennant, the clue which is about 20' off the deck is several feet behind the mast, his helps to move the center of effort closer to the mast, but with the other headsail have enough effort before the mast to balance it out. If I should decide to just fly the Yankee, I can adjust it's center of effort with the pennant.
 
#384 ·
In William Atkin's defense, I would like to point out that the Captain Cicero (originally the Kathrine S.) was a commission which the client decided not to have built. The name was changed to Captain Cicero and the plans were fist published in MotorBoating Magazine in 1945 as a "29'10" round bildged knockabout". That sailplan could have been from input from the client, I was told by a another source (which I am not entirely sure of) that the original rig was a gaffer with a bow sprit. The published sailplan and it's problems could have simply been from Atkin conceding to the requests of a client and/or an error in reconfiguration of a gaff rig. Though the published sail plan show main and working jib, there was an allowance for a jib topsail, this would have balanced things out a tad.

To any of you who have designed a boat and/or rig for a customer or had one designed for yourself, in most cases the customer has last say and it is up to the designer to convince the customer what will work and what wouldn't and why
 
#385 ·
I started to write something but wifi crashed and I lost it...so lets go again.
Of the "formulas" out there for performance, some are totally useless and can at best be used for comparative purposed and/or guide lines....some on the other hand are quite accurate. I am addressing the formula on hull speed in displacement vessels based on LWL. Though it is relatively accurate, variables in hull design do strech this formula a bit. While some boats find it very difficult to get to "theoretical hullspeed" (if at all), other have no problem at all and push the limits.
My boat has a LWL of 25' giving it a HS of 6.75kt. Under power 6.5kt at 2000rpm is a comfortable speed while 7kt at 2200rpm is possible (but that's my limit) but extremely inefficient for only a 1/2kt gain. 6.5kt is easily obtainable under sail or power (96% of HS or 1.3*sqrt of LWL).
Would you say 6.75kt is my "theoretical HS" while 7kt is my "obtainable HS" ?
If HS is the limit my hull can go through the water...the easily obtainable and maintainable 6.5 must be my cruising speed or some such thing.
For my purposes worring about a 1/2kt or less just isn't worth trouble
 
#386 · (Edited)
Wolfie, HS isn't a "limit" - it's a calculated value, related to LWL, and defined as the speed at which the wavelength of the boat's bow wave (in displacement mode) is equal to the boat length. That's all it is. There's nothing "theoretical" or "obtainable" about it. It doesn't take into account beam, hull shape, wave conditions, or anything else which might dictate the most "efficient" maximum speed through the water and was, IIRC, a means of categorizing racing yachts with wildly different LOD.

What you're referring to is something else entirely - usually referred to as "Boat Speed"... "BS" for short. :)
 
#388 ·
Wolfie, HS isn't a "limit" - it's a calculated value, related to LWL, and defined as the speed at which the wavelength of the boat's bow wave (in displacement mode) is equal to the boat length. That's all it is. There's nothing "theoretical" or "obtainable" about it. It doesn't take into account beam, hull shape, wave conditions, or anything else which might dictate the and was, IIRC, a means of categorizing racing yachts with wildly different LOD.

What you're referring to is something else entirely - usually referred to as "Boat Speed"... "BS" for short. :)
Thank you for setting that straight, I am not racing against another boat, and the calculation based solely on LWL is about 1/4kt off what appears to be the "most "efficient" maximum speed through the water" (to reach 6.5kt isn't difficult, anything else will require a bit more experimentation).I have always known there were so many variables involved that such simplistic formula could be accurate, though it was accurate enough (until you start splitting hairs). For my purposes what is important is to know what my boat is capable of and how to attain that.
The age, condition and cut of my sails leave alot to be desired...but considering what I can do with what I have got, I am not complaining...though I do realize that new sails will improve on what I have dramatically. As it will be a long time before I can afford new sails I plan on sailing with what I've got and trying other combinations and/or variations of used sails until I decide what will suit me best......then I will have a new suit of sails made. For my purposes I need to balance ease of use with performance.
 
#395 ·
NIGHT RUNNER wins Swifsture Race overall,,,,again!

My-Tai the Flying Tiger 10m that I designed won the Juan de Fuca race overall. That two years in a row with overall wins for the Tiger. Not bad.

That's two first overalls this year in the biggest race in the PNW.
Last year I had three first overalls. It was a good year. But the Baba 40 didn't race this year. That's Ok. I'm not greedy.

I know I posted almost the same thing before. I just thought some current reality might help here.
Attached Thumbnails
 
#401 ·
This has turned into a really kewl thread....originally a modern take on an old design...it has addressed hull design of various types, as well as rigging and sails and performance on all counts, to name a few things. Not mention things other than performance, but rather how a particular boat's importance to an individual "The perfect boat is a balance of an individual's priorities". I may have appeared as though I was so stubborn so as to not pay attention to what other people were saying...that is not true, I was just being defensive of an older though not obsolete design. Alot of what has been talked about would work great for a racing sailor in coastal waters with lot of money to accomplish that....some of what has filtered through works for us poor cruising sailors.
I will put alot of thought into my main before I have it made.
The only way I would have battens on my boat would be fully battened ($$$$!!!!)
Two reefs w/deep second reef, 8oz cloth, triple stitched,One question I would like to ask, when I take a sail into be checked out, the first thing they check is the condition of the stitching....there must be a better materiel than what is used for thread in sails
 
#404 · (Edited)
Thanks Med. I appreciate your comments.

Yep NIGHT RUNNER is a wonderful old boat that keeps on hanging in there with the newest rockets. I think especially on this thread it is helpful for some SailNetters to see a boat that can go around Cape Horn, cruise the South Pacific, race single handed to Hawaii and win consistantly against the best in the PNW racing fleet for 33 years all the while looking fabulous. And the crew loves the boat.

Today NR is an old war horse with a very tough PHRF rating but the boat can win in a breeze (last year) and can win the drifters (this year). My wife asked me tonight, "What makes it so fast?" My answer, "Not sure. But I know I tried hard to design a fast boat." There are major features to NR I'd like to change today to make the boat even faster but it doesn't seem necessary.

Ow! I think I just pulled a muscle patting myself on the back.

I "borrowed" that aft cabin/offset companionway detail from Phil Rhodes. I can't take credit for that. But thanks anyway.

I hope you have had the fun of driving NR. There is no boat like NR on a blast reach, balanced to perfection, two fingers lightly on the wheel, Doug with a big grin on his face and the crew having a great time.
 
#405 ·
Congratulations Bob. It says a lot about the advantages of a well rounded designs and skipper and crews who know thier boat.

I'm just back from 4 days out on the water and so am coming into this late.

Jeff
 
#409 ·
Her main is a Schattauer sails dacron main (a local hand done loft with a really good reputation for cruising sails). The main has the top 2 battens full, with the next 2 partial. One thing I found curious is that she doesn't have an adjustable outhaul. Instead she has a flattening reef.

35 year old (cold molded) wooden boat with a dacron main beating the pants off boats with thin glass hulls and carbon fiber masts. There's just something I really like about that. ;) Oh, and yes, she has been around the horn, as mentioned, so she's strong too.

MedSailor
 
#407 ·
For everyone's enlightenment here's the 'old girl' under discussion... Congrats, Bob.

 
#408 ·
I saw that batten silliness above.

Its funny; I have had perhaps a half a dozen mainsails with full- length battens and sailed on dozens of other boats with full batten mainsails. The battens and their pockets have never been the part of the sail that wore out. I do have sticki-back chafe patches on the pockets where the full length battens hit the shrouds on deep reaching and running angles, and I typically have added another layer at some point in the life of the sail.

The cost for my last mainsail included quotes for conventional and full length battens, and they were the same as the cost for both. Given the much longer sail life with the full length battens I opted for the full length battens. I did opt to splurge on high tech batten tension adjusters with a gauge and screw adjuster, and those added another $100 to the sail (less labor, more part costs).

The way that I see this, even if a battenless mainsail saved any money, it would be a false economy given the considerably shorter life these sails have. But then again, its not me buying these sails, but clearly there is a huge difference in my concern for durability and performance vs. theirs.

Jeff
 
#412 · (Edited)
I saw that batten silliness above.

Its funny; I have had perhaps a half a dozen mainsails with full- length battens and sailed on dozens of other boats with full batten mainsails. The battens and their pockets have never been the part of the sail that wore out. I do have sticki-back chafe patches on the pockets where the full length battens hit the shrouds on deep reaching and running angles, and I typically have added another layer at some point in the life of the sail.

The cost for my last mainsail included quotes for conventional and full length battens, and they were the same as the cost for both. Given the much longer sail life with the full length battens I opted for the full length battens. I did opt to splurge on high tech batten tension adjusters with a gauge and screw adjuster, and those added another $100 to the sail (less labor, more part costs).

The way that I see this, even if a battenless mainsail saved any money, it would be a false economy given the considerably shorter life these sails have. But then again, its not me buying these sails, but clearly there is a huge difference in my concern for durability and performance vs. theirs.

Jeff
You compared sail life w/ partial battens to full battens....did you also figure in life span of a batten-less sail? I agree that a sail w/ full length battens probably would last longer than partial .....but to put on a sail with full battens would mean I would have to replace the "T-track" on my mast and because my backstay position doesn't allow for much of any roach at all, the most it would accomplish is better sail shape and maybe ease of reefing. Add to the price of batten-less sail.....batten pockets, full length battens and track designed to take full length battens (I was quoted $1000 for just the track alone). My mast is laminated Sitka Spruce with a luff of 37'.

On a different note.... When growing up I used to ride a big old grey (horse) who was sort of stocky and showed his working lineage. The horse beat out quarter horses and other such "fancy" horses at shows. The judges referred to him as being an "athletic horse". The analogy to my boat is pretty close, she too is from a working lineage and though not as fast ....isn't as skittish as the race horse version of a sail boat.
For a 7ton wood boat w/ fullish keel, "antiquated" rig, old cut cruisng sails (blown out by racing standards), 16" three bladed prop, sailed by a cruisng sailor....I think she does pretty well. I never thought for a moment my boat was a racing boat...I would not of been so happy with if it were. I too am not a racing sailor, racing is too stressful for me...I sail to relax (though some people find relaxation in competition, can't see how, must be a byproduct of our culture).
 
#413 ·
Wolf:
You don't have to go full battens. You can go long, partial battens. That's what I had on my boat. I did have full battens at the top two but partial under that. Short battens were an artifact of the IOR rating rule. I would bet you could find a good used racing main that could be cut, if needed, to fit your boat for a very good price. I'd sure as hell exhaust that approach first before I bought a new sail. Some racing mains are discarded after one season of use.
 
#414 · (Edited)
Thanks Bob: I was going to go that route for jibs.....it's definitely worth a look. I am going to get all the appropriate measurements for my sail before I leave. I plan on spending several months in the San Fransisco area....should be able to find something down there and someone to do the appropriate modifications. Just the proportions 37'x15' aren't quite the same cut as a racing boat now adays, I have a couple of names of places in the bay area who deal in used sails.
 
#416 · (Edited)
Batten-less vs Fully Battened appears to be one of those things that has strong supporters for each (I have also heard of laminates being used in lew of fully battened, just to complicate matters). Add to that people only having an opinion that supports their application, then try and sort out valid data that applies to you from that that doesn't along with the invalid data. My personal choice is either fully battened or full/partial.
If you draw a straight line from the tack to the head the distance to the backstay is about 6" at the head (point of reference, the distance from head to masthead is 12", I admit boom is a tad shorter than in drawing). My boat does have a 2 1/2'+ boomkin, originally for a wind vane, which would allow me to relocated the bottom of the backstay and make room for a roach.


On another point using that fancy software some people here seem to have I would like to see two views one slice at static water line and two a slice at the boats preferred heel of about 25 degrees (use the hatch on the drawing between waterline and rub rail as the point where the waterline at heel is). This should explain a bit about how/why my boat behaves the way it does
 
#423 ·
Batten-less vs Fully Battened appears to be one of those things that has strong supporters for each (I have also heard of laminates being used in lew of fully battened, just to complicate matters). Add to that people only having an opinion that supports their application, then try and sort out valid data that applies to you from that that doesn't along with the invalid data. My personal choice is either fully battened or full/partial.
If you draw a straight line from the tack to the head the distance to the backstay is about 6" at the head (point of reference, the distance from head to masthead is 12", I admit boom is a tad shorter than in drawing). My boat does have a 2 1/2'+ boomkin, originally for a wind vane, which would allow me to relocated the bottom of the backstay and make room for a roach.
Wolf,

Now I understand where you are coming from and why you keep making the mistake you appear to be making. Last week you told us that your boom is 15 feet long. That image, which is a little different than the earlier sail plan that you had posted shows a boom which is approximately 16'-8 to 17'-0 depending on where the back of the mast its (its smudged when you blow it up to scale). So your boom is approximately 1'-8" to 2'-0" shorter than shown in the drawings. And that is why you have plenty of room for roach without overlapping your backstay by much. In reality, your sailmaker will need to measure this carefully. You should be fine with a higher quality dacron sail. You don't need to go with higher tech fabrics.

Jeff
 
#417 · (Edited)
Here are a couple of nice photos taken of NIGHT RUNNER during the Swiftsure Race last weekend.
Photos by JAN, thanks Jan.

I hate battenless mains. You can't control the shape and the draft moves too far aft. If you are after optimal performance there is no argument, you must have battens.
 

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#418 ·
I will keep your suggestion in mind when I am in a part of the world with enough racing so finding a "retired" racing sail that can be altered to fit my boat is possible.
Also when I have my main measured I will also have a variation taking into consideration moving the base of the backstay out onto the boomkin. Boomkin is an A-frame construction 2" thick laminated teak and bottom 6' of backstay is split which gives me two connection plates on the transom which can be easily moved. It's possible, just have to decide if it's worth the effort.
 
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