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Jul 02, 2009, 09:01 AM
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New keel and new flying jib sheeting method


Great sailing last evening with strong winds, 15g22mph. The ship sailed fast, maxing at 1ft/sec in a close reach. I started the cruise with topsail and topgallant squaresails, but struck the topgallant to reduce lee helm. The leeway was greater with the topsail than with only the f&a sails of previous voyages. Or it could have been due to the new, smaller keel plus more heeling in the stronger winds. I could beat to windward, though. My course made good on a beat was lower than under f&a sails, but the wind was significantly stronger, so that may have been a factor. So, the paintings of topsail schooners beating with squares set may not be in error after all :-). My tacking was iffy, but wears were rock solid with the squaresail and modified rudder.

The rudder, even with a "steering oar" extention, would not dominate the hull; steering was dominated by the sails, slackening the mainsail boom to wear, hardening up to tack. The rudder assisted wears, reducing the ground lost to leeward. It had less effect on tacks. Even when traveling fast, a rudder command to headup was only good for a short span, then the wind force on the sails would cause the bow to fall off, unless the mainsail was sheeted in tight enough to center on the hull. The steering oar would not scull the stern around in a failed tack, a technique I can use in the barque in mild winds. Pehaps the sculling will work for the Baltimore in less wind.

Due to a mistake on my rigging last night, I could only get the mainsail to center on the hull (tight sheet) on one side, thus could only tack in one direction. The ship, in these conditions, would tack quickly as long as I could get the mainsail on the centerline to weathervane the hull. Dumb thumbs spoiled several attempts; I am used to the rudder being on the right stick, but for the Baltimore, I've moved it to the left. Consequently, I'd often screw up the coordination of rudder and yardswing at a critical point. When I was only sailing under f&a sails, these goofs were not as critical :-).

I used a new keel, trying to reduce wetted surface area. It's about 10cmx26cm, half the size of the barque keel used last cruise. Jenny supplied a recycled plastic file folder. I just cut a 20x26cm piece, folded it around the original footy lath keel, and bolted it on in 2 places. I also taped the trailing edge with black electrician's tape, but that tape was not waterproof; the trailing edge stayed thin, though, due to the bolts, and bits of tape that retained stickum. Marine Goop would probably work to hold the trailing edge, but I was too impatient to wait for glue to dry. I also removed all internal ballast, and went with about 12 oz of lead shot in the keel. An offcut from the plastic was taped to the rudder to give it a more steering oar-like shape.

I had persistant lee helm last night, undesireable. I'm not sure whether it was due to the new keel with less area, or the topsail, or something else. The hull was trimed down by the head, the keel was bolted to the calculated CE, and there was a good heel. All these factors should have produced weather helm. The only underwater difference was the extra area on the rudder; since this is located aft, it would act to reduce weather helm; but even when I gave full rudder to point up, thus reducing the effective area of the rudder, it did not seem to affect the course of the vessel. I'm still puzzling over this one.

I solved the flying jib clew-crossover problem by sheeting the (original Tyvek) jib to the lowest yard arms, port and starboard. Thus, when the yard is braced to a new tack, it drags the flying jib clew over the inner jib luff. It worked like a charm. I had to raise the hoist of the jib to bring it's clew inline with the yardarms. If I wanted to try the technique with lower clew jibs, I'd need to rig turning blocks. It takes some fiddling to get the lengths of the sheets correct; they need to be tight enough to hold the flying jib on a beat, but loose enough to allow the clew to cross over the outer jib luff when the yard swings to the new tack.

Due to the geometry of braces, the schooner's squaresails will swing farther than the servo arm commands. That is, on a beat, the sails will brace more sharply, under wind pressure, than you'd expect from a bench test. That is a good thing, because you want your yards to swing more than 45deg per side to get good performance on a beat. This extra swing also means that I don't need to add a servo stretcher (electronic device to increase servo throw). I do set the servo travel at 150% on my Spektrum tx, but that is not enough throw for squaresail bracing with my barque. The difference between ships is due to the location of the brace turning blocks: on the schooner, they are on the centerline, while on the barque, they are offset 1" on either side. With lines running from the center, as the schooner yard swings, the windward brace slackens. This allows the wind to press the yard farther around. On the barque, there is true parallelogram motion, with no slack in the braces. But on the schooner, that parallelogram is distorted by the bead blocks' location, in this case allowing a fortuitous increase in yard swing.
Last edited by Brooks; Jul 02, 2009 at 09:12 AM.
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Jul 02, 2009, 09:39 AM
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I may need to change my battery setup. While derigging after last night's cruise, I noticed the alkaline AA's were warm. They had given off an "electronic" smell on previous cruises (both Duracell Ultra's and a set of Kirkland, a house brand). I may have to go to rechargable NiCd's or NiMH's.

I think under strong winds the current drain is getting excessive for alkalines, even for this small vessel. I'd experienced a similar problem with the big barque, but did not expect a problem with the schooner.
Jul 02, 2009, 01:13 PM
**NOT GUILTY**
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Quote:
Originally Posted by Brooks
Capt.Crash, you are the topsail schooner expert. Have you ever worked to windward while flying your square topsails?
Brooks...I've only rigged and sailed with the squares a couple of times. The pond we use is not big enough due to no place to beach the boat when in trouble...it's either the wall or the inaccessible island or tall rushes of pond weeds. It's very hard to slow down and grab this big heavy boat with just the schooner rig so I don't even try it with the squares.

When I did sail with them...I was not very good at tacking up wind. The top sails are attached to the sails below by means of lines or rubbers at the ends of the yards...allowing the sails to have a lot of for lack of a better word "play" and no way to hold them in a stationary position. The only square sail that is under complete RC control is the main.

Crash
Jul 03, 2009, 06:47 PM
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Crash, I am having trouble tacking with the topsail hoisted. So, if you have dangerous/inacessable shores, sailing under F&A only is good seamanship. My schooner looks cool under F&A only (the 3 jibs are so distinctive), so that's ok with me, aesthetically. I have not given up on the squares, so will continue to try them.

I did some experimental sailing yesterday, trying both keels, and with and without the topsail. The only fairly reliable tacks came w/o squaresails and with the old barque keel, the big one. My new keel, 1/2 size with the green airfoil was a failure. I had great hopes for that one.... Obviously I don't know everything yet, hoho.

Have a nice Fourth of July, you have a very historic and patriotic ship.
Jul 05, 2009, 08:32 PM
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Green keel improved


Good sail this evening with the new keel. I had left the ends of the green plastic wrapper open, per the above photo. That was a mistake, the edge effects were apparently extremely detrimental to speed and acceleration potential. Once I pinched the ends shut and secured them with strapping tape (seems more waterproof than electric tape), the keel & boat worked fine. On a close reach, she would scoot. The boat would accelerate, with the green keel, much better than with the wooden barque keel. The wooden keel is, admittedly, in bad shape, with ripples and delamination of the plywood, so there is a lot of surface drag. The slick green plastic does not suffer this problem.

This keel needed to be installed about 1" fore of the CE, unlike the wooden keel, which worked best on the CE. When installed thusly, I had a small amount of weather helm, and working to windward was easier than previous, lee helm, cruises. I think the cutaway of the bottle at the bow, (molded-in by the bottle manufacturer to produce the bottle shoulder), requires keel area forward to compensate. I'd like to try a keel with area forward and weight aft. Right now, the schooner sails bow low, stern high, and would look more elegant with a more level waterline, I think. Of course, this was the look of 1600's galleons and pirate ships, so a rig change to all squares, and the boat would look authentic :-)

This cruise was F&A sails only. I was interested in developing effective beats and tacks.

Tacking, in puffs/gusts was fairly easy to perform. In a puff, the boat would accelerate, and spin around under rudder control, tacking quickly. Coordination of rudder and mainsheet was still needed, so it's still a 2-handed Tx event. Lulls were deadly to tacks, though I could still wear. In lulls, the boat would often run out of speed and stop the turn either head-to-wind, or sooner. If stalled head-to-wind, I could sometimes save the tack by reversing rudder. With the steering oar attachment, the rudder was effective with sternway. I imagine tacks with the squaresails set might need this rudder reversal; I use it when tacking the barque in light winds, and real clipperships would do likewise.

The windage of the bottle was apparent. The boat would be beating, and a puff would slide it sideways a few inches. I did not see such sideways slides with the larger wooden keel, so the greater area does help resist leeway in gusty winds. A half-bottle boat, per Andrew's modified bottle boat design, would probably not suffer as much windage loss.

I tried to make a tacking movie, but needed another hand to both sail and film, alas. If I'd got the camera out before the wind started to die, I might have been able to cobble together a rudder-only tack, so I'll try that next time. Or I could try putting rudder and sheet on the same joystick...watchout lee shore, roust out the Coast Guard :-)

Summary - The bottle schooner works better each time as I gain experience. I still need to remember *tiny* control movements of mainsail sheet work best. There are still details that I can debug, I feel, to improve performance. If you have the patience to learn new sailing skills, the bottle schooner is a pretty cheap way to move from sloop to multimast sailing.
Jul 05, 2009, 08:52 PM
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Update: When I calculated the Center of Lateral Resistance (CLR) of the big keel (treated as a wing), and compared it to the CLR of the green keel (also treated as a wing), it turns out that both CLR's were positioned in the same place, right under the foremast. Just judging by flat plate area, the CLR's are different, with the smaller keel fore of the big keel. But when judged as wing-like bodies, the CLR's turned out to be in the same place for both keels.

Moral - remember that lifting bodies don't work the same as drag bodies. Jeese, I should have remembered that from my experiments with different keels when testing the barque *sheepish grin*. Well, at least the "anomoly" I thought I was seeing in keel position is cleared up :-).

The center of lift (CoL) of a wing is conventionally assumed to be at the 1/4 chord point. I find that treating the CLR of a keel as equal to the CoL of a wing helps in boat design for my model windjammers. In fact, treating sailing as flying, physics-wise, clears up a lot of "rules of thumb" and "secret design knowlege" in the historic record of nautical architecture.
Jul 06, 2009, 03:01 AM
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Schooner Bottle Boat


Brooks, I'm very glad you are getting so much out of her and it is lovely to read your eloquent and detailed reports. Thank you for sharing it with us.

Walt Hollinger (USA) also fared the bow of his 3ltr Bottle from the bow to the keel.
I did look for a photo but could not find one.

Best wishes
Rgds
AndyT
Jul 13, 2009, 09:02 PM
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The schooner did very well in strong winds 18gust23mph. I could tack at will and wear relatively easily. The only limit on the wear was that I needed to start the maneuver before approaching too close to shore. She'd spin on a dime for tacks, but the turn circle of wears is bigger. This ship likes strong wind, a true seagoing vessel. She was a lot of fun to see handling the big wind. This was a F&A cruise, as the strong winds suggested reducing sail aloft (the squares) before heading out.

Speed was good, enough for the footy-style deep, narrow chord rudder (still with the green plastic swimfin addition) to work very well. I could control most weather helm in a gust with rudder alone. Occasionally, especially if I was inattentive and let the boat head up to shiver, I'd need to slack the main a bit. Most of the time this was sufficient to regain control on the original tack. But if I was late (fumbling with the camera, say), even reversal of rudder as she drifted astern might not get the boat back on course. In this situation, the boat would perform an unplanned tack. Pure captain error, these tacks, as I could easily beat on course, even through the gusts, if I paid attention.

I used the big barque fin keel. I've decided that this boat, unlike the sandbagger bottle boat, simply won't perform reliably with the green keel. As the ship development moves from the experimental phase, I am implimenting improvements. Today's was a new lead weight. I replaced the fat, flat-ended pill bottle with a piece of 3/4" PVC pipe. The pipe length was sized to hold the same lead shot as was in the pill bottle, about 1# 3oz. (net of pipe displacement; I don't fill the tube with water before capping, so have to account for the tube's displacement when calculating actual righting force). End caps were tapered at the joint, and glued on. I've used the same style keel weight in the barqe. The schooner tacked the best she's ever done, either due to the slicker keel, or due to the stronger winds.

After about 10 mintues of sailing, I thought she was riding lower in the water than expected, so brought her back. I dumped about a cup of water out of the hull. The second cruise collected no water, under the same wind conditions. I suspect I did not screw the bottle cap on correctly at the start - the old landlubber's mistake of mishandling the boat's drain plug, hoho.

As mentioned previously, I transferred the controls to 1 joystick so as to have a hand free for the camera. And, as predicted previously, seamanship under film suffered *grin*. Out of 10 movies shot on site, only 4 provided usuable film....just like Hollywood, I must be a professional, *grin*. One problem, the boat looked so pretty I would start watching it instead of the camera screen....many of my best tacks & wears never made it into the frame. I have to wait for John to return from his trip to post them, my dialup is just tooooo slow.
Jul 15, 2009, 02:33 PM
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Movie posted


https://www.rcgroups.com/forums/show...3#post12665932

Movies of the sandbagger chasing the schooner now posted. 7/16/09
Last edited by Brooks; Jul 16, 2009 at 02:04 PM. Reason: New movies available
Jul 15, 2009, 06:34 PM
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Sailing under topsails


The topsails did not prohibit working to windward in light zephrs. I think they cut down the beat angle, as you might expect. I'd guess it ended up between the angle of F&A only, and the angle of the barque, say 5 pts off the wind (F&A) vs. 6 pts off (with added topsails). For comparison, the sandbagger looks to make good at 4 pts off, what you'd expect from a sloop. The topsails did help tacks when the ship was too far off shore to easily judge angles; once the bow crossed the eye of the wind, the backed topsails would obviously speed the rotation of the hull, giving me a good clue to haul the braces to the new tack and center the rudder.

Zephrs are not the schooner's favorite winds, I'll have to see how she performs under topsails with a good schooner breeze. A photo of Pride of Baltimore II shows her beating with a single topsail.
-------
Fun time at the pond, for the shoreside watchers. Not so fun for the poor schooner sailors, viciously pursued by Pyrates in a large sloop.
More Photos at Sandbagger thread:
https://www.rcgroups.com/forums/show...1#post12640078
Movies to be posted (see previous post)
Jul 29, 2009, 06:44 PM
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Double topsails work fine in a good breeze


Nice wind, 7-10mph. The boat would tack and wear, and scoot along in a beam reach. With these winds, she probably moved as fast as the sandbagger in a 5mph wind. Some gusts really laid her over, though none qualified as a knockdown. I was using the big, barque keel. The schooner maintained speed throughout the gust, and showed good speed at all times. This boat is a joy to sail, with enough wind :-)

Working to windward was no problem with the topsail and topgallant set. My yard swing is more than 60 deg off center. Thus, the Squaresails, on this boat, produce similar force vectors during the beat as Fore&Aft sails produce. In fact, with my new brace rigging, I have to limit yard swing via the computer radio. Otherwise, they would swing a full 90 deg, and produce only leeway, not forward thrust.

I re-rigged the braces, testing a new configuration for another schooner under construction. Just as I doubled sheet travel by rigging the sandbagger servo arm to pull on the bight of the sheet, rather than pull on the bitter end, I doubled brace travel using the same idea. Doubling the haul allowed me to move the brace2yard attachment point out along the yard, farther from the mast. On real ships, the braces are attached at the end (yardarm). At that location, they clear the gaff of the foresail (the big fore&aft sail set on the foremast). Since I am not using winches, I have only limited haul, so have to move my braces inboard from the real ship location. In my original yard location, the braces interferred with the set of the foresail. The new location does not interferr as much with the foresail, so I presumably get more power out of the sail. It certainly looks nicer without the brace creasing the leach.

Trigonometry - When I first set the new brace location, I reasoned "since I get double the haul, I can double the distance (from the mast) for the brace2yard attachment". Oops. The yard-swing vs haul-needed does not scale linearly. I had to move the braces back inboard, ending up with them at 1 1/2 times the original distance from the mast. My advice to builders: test your brace locations, just taping them to the yard, while you see if you got the geometry right :-). A computer radio, with adjustable servo travel, is a real help when debugging a square-rigger.

Photo taken during a lull, nearshore. I was standing on the windward shore, and the best wind was farther out to sea, beyond good camera range. I have a couple movies that I'll take to John for uploading.
Last edited by Brooks; Jul 29, 2009 at 07:11 PM.
Sep 05, 2009, 04:05 PM
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Summary:
The bottleboat topsail schooner works fine in winds of 7-20mph. Wind under 7mph means slow sailing and more drift to leeward. Aldebaran (my larger topsail schooner) is a wizard in light winds, so the topsail rig is capable of superior performance in a drifter; the bottle schooner loses due to the exposed hull windage.

The ship needs a big keel (lots of area) to resist the leeward drift due to the large amount of freeboard with it's consequent windage losses. Aldebaran does not need the large keel surface area, so the bottleboat's need is not inherent in the rig, but in the bottle hull. A half-bottle hull, per Andy's revised design, would probably reduce windage and the necessity of the large keel.

Squaresails on the foremast do not prohibit sailing to windward. They may cut down the angle you can point up during a beat, but are a great help in tacking. Their assistance in other points of sailing is easy to see, both in increased boat speed and in increased maneuverability.
------
Photos: The final keel.
The yard and boom attachments via screweyes.
Last edited by Brooks; Sep 06, 2009 at 06:02 AM.
Apr 25, 2010, 02:58 PM
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Back in the water


Sailed Bottle Baltimore yesterday and this morning. Yesterday's sail was not too impressive. I had battery trouble, only getting in 15 minutes before she started losing rx-tx control. Also, she did not sail well to windward. After getting home, I discovered that I had not trimmed the foresail properly, the sheet was too slack, and also the foregaff halyard was not hauled taut. Fixed those problems, and tried again today.

This morning's sail was very nice :-). The topsail schooner would tack and wear, as you can see in the video. Speed was good, better than I remembered. She could sail and tack well even in light-moderate winds, though I don't expect she'd do well in zephers (unlike my topsail schooner Aldebaran, the light air magician).

Batteries (4 AA, 1500mah NiMH) lasted for 45 minutes. This still seems short, to me. I don't know if there is an unwanted current drain, or if the forces on the servo are higher than expected. When I open up the hull to remove the batteries for recharge, there is always a sharp battery smell in the peanutbutter jar holding all the electronics. This has occurred with both alkaline and NiMH batteries I've used. Any ideas?

The foresail trim problem/solution reminded me that "the smaller the boat, the more sensitive she is to small sail trim changes" :-) It's worth going over your small craft before every launch to make sure all sails are trimmed to give as nice a shape as possible. I forgot to do that yesterday. The small sails really don't tolerate poor shape as well as a larger craft's sails might tolerate the same flaws. But she's a fun little craft when she's set up correctly :-)
Last edited by Brooks; Apr 25, 2010 at 04:58 PM.
Apr 25, 2010, 03:13 PM
Diver-driver
meatbomber's Avatar
thats such a nice sailplan Brooks i`m surprised that you`re using up so much energy... i`m running a 2S 200mAh Lipo with a BEC on St. Helena and last time i charged her i sailed for 2 hours at least and only charged back 150mAh.
I guess you´re having a short somewhere that`s using up all your power.

Have you ever thought about transfering mast and RC into a bit smaller hull ?
Apr 25, 2010, 06:34 PM
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No, but I've thought of going to a BIGGER hull, you Munchkin :-))

(btw, Munchkins are little people in the Wizard of Oz stories by Frank Baum, I should have maybe explained since Czech Republic favorite films/books are probably not same as US favorites. You can get Czech subtitles for the 1939 Wizard of Oz movie).

http://en.wikipedia.org/wiki/The_Wonderful_Wizard_of_Oz
Last edited by Brooks; Apr 27, 2010 at 05:08 PM.


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