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Old Mar 02, 2011, 11:43 AM
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Bozeman, Montana, United States
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Bottle Brig

Continuing my OceanSpray Cranapple bottle fleet - Sandbagger sloop, topsail schooner, now a brig :-)

This brig's hull is cut from the same style bottle as my previous ships. But, this hull is rotated 90 deg from the previous hulls. The resulting brig hull is long and narrow, as opposed to the long and wide orientation of the sloop and schooner hulls. To reduce the freeboard, I cut the side off the bottle, lowering the shear line. To keep the now open hull from sinking if she heels too far, I've taped foam inside. Build details are similar to my previous ships, which you can see here:
Sandbagger:
http://www.rcgroups.com/forums/showthread.php?t=1078321
Bottle Baltimore topsail schooner:
http://www.rcgroups.com/forums/showthread.php?t=1071509

The brig will be a free sailer and sinker. The purpose of the ship is to be the target for submarine attacks. The fin keel will drop it's ballast when rammed by the sub. The amount, and placement, of the foam will be adjusted to leave the sunken ship floating with the bowsprit and part of the bow exposed. The keel and ballast drop trigger design is experimental; I'll post details if it works; ditto for the rubberband powered Nautilus :-)

I expect to make an RC version once I've debugged the design. Right now, there is little open water in Montana for testing - I'd need to add skates to brig and sub to get them out on the water :-).
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Old Mar 03, 2011, 01:49 PM
Square-rigger
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Klatovy, Czech Republic
Joined Mar 2004
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YEAY a new Brooks ship looking great my friend ! can`t wait to see her on the water! I do love teh Somers sailplan.
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Old Mar 03, 2011, 08:12 PM
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Hi MB - I fit 3, HS-82mg servos on the top of the peanut butter jar lid (mounting like for the other 2 bottle boats, though they only have 2 servos each). If I can make the 3 servo arms swing w/o interfering with each other, should be doable. I'm trying a boomerang shape for the arms. I'll let you know if they work :-)
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Old Mar 12, 2011, 05:23 PM
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Sinking the Brig

The Flapper-Keel works - when the flap is hit by the rubberband powered submarine, the keel drops the lead ballast. This leaves the ship down by the stern, and she quickly sinks, ending up half-afloat, in a bow-high configuration.

Details of the mechanism: The plywood Keel and Flapper are attached to the Fin support aluminum strip (flapper attached via a brass hinge). The fin support is bolted to the aluminum L-shape Boat keel. There are multiple holes in the boat keel to allow gross adjustments of the flapper-keel unit.The fin support has a slot for the bolt so that the unit may be slid fore&aft to fine-tune the balance of CLR vs CE. I've successfully employed this keel attachment scheme in my other boats, both RC and free-sailing.

The Flapper-Keel lock is comprized of 2 short sections of brass tube, each glued to the wooden flapper or keel. The flapper is locked to the keel, either by a thin toothpick spanning the gap, or a single strand of rubber band ditto. Ramming the flapper either snaps the toothpick, or stretches the rubberband, allowing the flapper to swing. The rubberband is easier for the sub.

Ballast is hung from a pivoting, L-shaped, brass rod. A Pin and string keeps the rod in place. When the Flapper swings, a 2nd string pulls the Pin, allowing the Ballast to slip off the rod. A 3rd string, leading from ballast to the boat keel, keeps the ballast from disappearing into the deep - a rubberband acts as a shock absorber to avoid damaging the boat keel by the jerk of falling ballast.

The sub was successful in 2/2 attempts to sink the brig when the sub struck the flapper. Striking the keel was unsuccessful, however. Apparently the inertia of the ballast keeps the keel from moving and unlocking the keel from the flapper.

In all tests today, the brig was stationary; hitting a moving flapper or keel may give different results. Also, we'll need to see if the rubberband is stiff enough to keep the flapper from pulling the pin while the brig is sailing.

We didn't get any shots of the sub sinking the brig, have to film them next time :-)

My thanks to Jenny for handling the photography - only a few photos due to my need for her 2nd set of hands during testing of the vessels.
-------------
Having trouble posting the video, will try later...

In the video, the brig is anchored. There was no wind to sail, and we were operating immediately upstream of a diversion dam spillway - because of low water in the river (less than knee-deep at the spillway), there was no danger to humans, only possible loss of the boats if they got swept away.

I tap the flapper with a stick. As you can see, I didn't need to shove the brig over, the movement astern of the dropping ballast was sufficient to cause foundering. The water was not quite deep enough to let the ballast hang free in the video. In a deeper area, where the ballast was not striking the bottom, the ship assumed a vertical position, with the bowsprit pointing straight up - quite dramatic :-).
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Old Mar 12, 2011, 08:55 PM
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Before and after photos of the sinking.

Submarine discussion here:
http://www.rcgroups.com/forums/showthread.php?t=1405510
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Old Mar 13, 2011, 07:22 PM
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Brig on the water

Couple shots of the brig in a pool on the river. Not enough wind for a good sail, too many trees blocking the breeze. The brig would respond to zephr puffs, I think she's going to be fine on the pond, once the ice breaks up.
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Old Mar 14, 2011, 02:41 AM
Square-rigger
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Klatovy, Czech Republic
Joined Mar 2004
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She looks great wonder how she will perform hunting that bottle baltimor
Are you gonna make a less wide chord keel for RC sailing her Brooks ?
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Old Mar 14, 2011, 07:57 AM
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Keel chord will depend on how fast she sails; faster=>more effective keel, thus it can have a smaller chord. The sandbagger's chord is about half what you see above. That'd be easy to achieve, just remove the flapper :-). Right now, brig is under-ballasted (it's what wheel weights I could stuff into the pill bottle; more airspace left than when I use lead shot). So, her freeboard is more than designed, which means her windage is also more. High windage from the BottleBaltimore's hull is one reason I needed the wide chord keel on that ship.
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Old Mar 20, 2011, 07:03 AM
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Poke brig with stick video posted:
http://www.rcgroups.com/forums/showthread.php?t=1409501

For some reason, rcgroups' "Advanced upload" no longer works for me with videos (.mov or .zip). Advanced still works with .jpg pictures, though, go figure...
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Old Apr 01, 2011, 05:29 PM
Scale Model Video
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Wow! Quite an elaborate submerged craft there, Brooks!
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Old Apr 05, 2011, 06:34 PM
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Sailing report

John and I sailed the brig in good winds, 10 gust 12mph before lunch, 12 gust to 15 after lunch. She did well, beating on both tacks, and made one reach clear across the pond. I estimate she makes good about 1 to 1 1/2 points to windward on the beat. Beats were easier to set up than reaches; I need to alter the fin keel attachment to allow me to shift the fin farther aft for reaches and runs.

I think she'd be capable of even higher pointing, but, with a free sailer, it's wise to be conservative. If you set up the boat to point too high, and she gets taken aback, there is nothing the shore-bound skipper can do. With the lighter winds before lunch, she would actually recover from minor taken-aback events, something I'd never seen with my freesailing brigantine. She'd luff, the sails would go aback, but almost immediately her sternway would swing the bow away from the wind and the sails would refill on the original course.

But for major taken-aback events in the stronger wind after lunch, she'd develop a prolonged stern board, drive the transom under, and founder. I'd read about this loss scenario for real ships, but had never seen it until this afternoon.

Once foundered, she'd ride bow high (due to the distribution of the styrofoam floatation in the hull). The higher squares on both masts were exposed to the wind. They'd be aback, and the brig would actually sail backwards about 3 points off the wind. She'd not drift directly downwind, but would make some sternway :-).

While beating, not much water came aboard. This was an unexpected bonus, since the hull is entirely open. For most gusts, the ship heeled a bit more, spilled air, and never dipped the leeward rail. But cruising after lunch, when the wind had picked up (and before I reduced sail), gusts could cause a foundering due to downflooding over the leeward rail. Fortunately, the wind held and the wreck would make it's way back to shore. I say fortunately, because I was unable to snag the brig's painter with my tugboat's towline to effect a rescue.

Wind speed & sail selection must be matched, like all my squareriggers. Striking both fore and main royals had a marked effect to the good, reducing heel. They are small sails, but do contribute to the acceleration of the hull in the lulls, so are best left flying if at all possible.

A movie Will Be posted (darn upload died at 98% completed, sigh):
http://www.rcgroups.com/forums/showthread.php?t=1409501
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Old Apr 05, 2011, 11:55 PM
Square-rigger
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Klatovy, Czech Republic
Joined Mar 2004
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love the Somers sailplan when are you gonna RC her Brooks ? She seems quite a bit arger than your bottle baltimor, if not in displacement then at least in sail area
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Old Apr 06, 2011, 07:57 AM
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RC is about half done, I've gotten sidetracked with sub operations :-). Since the open hull does not sink as easily as I expected (at least on the beat and close reach), I am encouraged to proceed with an RC version. The excess-heeling sinkings were all my fault since I delayed reducing sail; can't blame the ship for that. The taken-aback sinkings would not be as frequent if I could control yards and rudder, I think, so RC has attractions. Plus, filling the stern space with foam (left empty for the bow-high-foundering-scenario) would make founderings less a problem anyway. But for a target, whose mission is to sink, I decided that RC would be a needless complication.

The bottle is the same size as Baltimore, but with a better fineness ratio length to width (2.2 Baltimore, 2.9 Brig. For comparision, CSS Alabama, a notably speedy vessel, has a fineness ratio of 7). The Brig's sails are 25% larger than scale (based on the bottle hull's length). Of course, some might say that anyone who uses the word "scale" in the same sentence as "bottle hull" would deserve a flogging *ho ho*. Sail area is slightly smaller than Baltimore; I wanted to make it more than Baltimore since Baltimore seems to require strong winds to perform well. But, to achieve that I'd have had to lengthen the yards too much for good looks. Ballast is about 1/2 what I planned, due to inability to cram as many wheel weights in the pill bottle as I wanted. But the lesser ballast worked fine, so I'll leave it alone. The better hull configuration vs Baltimore, makes a big difference to speed, I think. Won't know for sure until we race them.

The Brig is faster than I expected. The long reach across the pond came about when she scooted out of my reach :-). This cruise was after lunch, and she'd already experienced some founderings while on a beat. I wanted to trim her for a reach to see how seaworthy she'd be.

After adjusting yards and spanker, I set her in the water, hoping for a 100' cruise across the bay. But, she pointed higher than expected, and took off across the whole pond (about 400' to opposite shore).

I expected her to founder, so went back to my car to prepare the rescue tug. What with rebinding the rx, and so on, I took so long to get the tug ready, that the brig had already zipped across the pond by the time I was ready to launch the tug *smiles*. So, she does fine on a close reach in gusty winds.

The return cruise (broad reach) was not so successful, though, with repeated founderings. I'd wait for ship to drift/reverse-sail to shore, tinker, and relaunch. The problem was that I could not move the keel aft enough to prevent the ship from heading up in a gust. Once she was aback, she'd bury her transom, etc.

Other than the broad reaching trouble, though, she sailed better than I expected. She looked a bonny craft at sea, to be sure :-).
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Last edited by Brooks; Apr 06, 2011 at 08:11 AM.
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Old Apr 06, 2011, 08:09 AM
Square-rigger
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Klatovy, Czech Republic
Joined Mar 2004
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yea its something weird that square rigger models seem to have a tendency to accelerate 2 times as fast backwards than forwards

I can`t really recall my Somers have a very strong tendency to head up in gusts when on a reach. maybe teh fine hull with a full length keel and then the wide chord fin and rudder are in comparison giving more heading stability.
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Old Apr 06, 2011, 08:36 AM
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My jibs are smaller than yours (non-overlapping too). And the Fore staysail is not only tiny, but is blanketed by the forecourse. So my forward balancing sails are outperformed by the large spanker, I think, leading to unbalance. On the freesailing Brigantine, the even bigger mainsail is totally controlling of heading; even on a beat I don't sheet in as far as I'd like. I just miscalculated the brig's balance of CE vs CLR, and ended up with the fin too far forward for reaching. I can fix that with a keel extension aft.

Speed was about 1/2 ft per second on the beat. That would yield a favorable speed ratio for Nautilus attacks. So, I may not worry about reaching and running ability.
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