Jerry Todd's Radio-Controlled Square-riggers


Specifications

Model Name Source Plans Scale Length over the rig Beam Height no keel Height with keel Sailing Weight Keel Weight
Constellation National Archives 1:36 96" 13-5/8" 65" 69" 100 lb 43 lb
Pride of Baltimore Thomas Gilmer 1:20 81.5" 13.6" 61.6" 70 lb
HMS Macedonian Howard Chapelle 1:36 85.75" 13.5" 60.8" 63.4" 100 lb 40 lb
Gazela Primeiro Gerald Todd 1:36 65" 9" 39.2 70 lb est


Electronics

My models run on a 6 volt, 7 amp-hour sealed lead acid (SLA) battery that powers the reciver and all the servos. No servos are altered in any way in structure or wiring. Each servo is fused with a 2 amp fast acting fuse, and the entire system is under a 7 amp fuse. The rudder servo is connected directly to the receiver and is not fused. The system is turned on and off at a double-pole-double-throw switch mounted under the skylight in from of the ship's wheel. In the off position, the switch routes the charging leads right to the battery, where I can connect a 6 volt 2 amp charger to it.

wiring_diagram.jpg

The Sliding Brace Winch

A long time ago Dan Lewandowski and I discussed the various means of dealing with the slack in braces when using winches and braces at the ends of the yard, as prototypes are. One idea we touched on was a servo that moved to take up that slack, instead of using bungee or springs on the brace itself as most of us were doing. Dan actually implemented the idea in his brig Syren. It's actually quite simple and I think, elegant system.

The winch servo is mounted on blocks that slide on rods. Springs on the rods push the servo back against the braces maintaining tension

servo_sliding_brace_winch.jpg

Constellation and Macedonian both have servo trays made up with two such rigs on each tray; one for the foremast braces, the other for the main & mizzen braces.

con20150526b.jpg servos.jpg

The servo with the semaphore arms controls the driver sheet and heads'l sheets - which I'll explain below. On either side are the winch servos that control the yard braces; those of the foremast on the right, and the mainmast and mizzenmast on the left. (The winch drums are not mounted in this image). In the center are the fuses for each servo and all the wire connections. The aluminum plates attached to the winches are fairleads to guide the braces onto their winch drums. All of this is mounted on a 3/8" plywood pallet that itself is screwed to the equipment deck in the model's hull. Both Constellation and Macedonian get identical set-ups.

Another nice feature of this set-up is if a winch servo needs to be replaced, remove 5 screws and pull one plug and it's out. 1 screw holds the winch drum, the other 4 mount it to the Delrin sliding mounting blocks. No alteration is made to the servo at all. If the entire servo assembly needs to be removed, pull two cotter pins that keep the brass rods in the aluminum end brackets, the rods slide out and the servo winch, drum, fairlead, all can be removed. The entire assembly can be removed by removing 4 mounted screws in the end brackets and unplugging the servo.

The Semaphore Jib-Sheeter

There are two usual ways used to deal with overlapping sails: 1. Don't; cut the sail so it doesn't over lap and sheet it to a ring mounted on the stay behind it. 2. Use a winch and haul the sail over while paying out the other sheet at the same rate. The does a poor job of sheeting out when sailing off the wind and puts a lot of stress on everything because both sheets are always under tension.

When you come about in a real boat with a sail that over-laps, like a jib, you cast off the sheet as you turn into the wind, let the wind help you carry the sail across and sheet it in on the opposite side. You might also resheet it on it's original side to help push the bow across the eye of the wind. The Semaphore Jib-Sheeter allows for just that!

jibsheets3.jpg

In the case of Constellation and Macedonian, besides the heads'ls, the servo arm itself will also control the driver/spanker sheet via a fairlead between the heads'l fairleads shown. That way it does the same job when it moves in either direction. This setup will control all the fore-n-aft sails on Pride of Baltimore; heads'ls, fores'l, and main. Another servo will control the square tops'l.

Self-Tending Bowlines

Another item of interest to the RC square-rigger will be working bowlines. Bowlines attach the the edge of a square sail and run to a block somewhere forward and to the deck. They haul and hold the edge of the sail forward when sailing close-hauled. This keeps the leech from getting back-winded. The image calls them Auto-tending, but I refer to them as "Self-Tending Bowlines."

bowlines.jpg

Tacks

The lower squares are loose-footed, ie they don't have a yard, which makes handling them difficult for the RC modeler. Many modelers handle is with some manner of approximating a yard at the sail's foot. One way that was actually used was a yard under the coarse something like a spinnaker pole for square-riggers. (Bendix boom or some such name as that). A rod attached, or inserted into the lower hem of the sail. Stiff wire false clew lines that hold the clews out, instead of hauling them in. Rods inserted into the leeches of the sail. And so on.

All of these interfere with being able to furl the sail in some manner, and I want to have that option. In looking at the problem I realized that on my model the tack was really more important than the sheet when sailing close to the wind because they function much like the bowlines described above, pulling the clew forward to keep the wind behind the sail instead of back-winding it. The opposite sheet hauls it's clew aft. I've added drums on the winches for the fore and main tacks. The sheets will simply run through the hull, the winch control will be on the tacks.

Control Line Routing Below Deck

Here's a diagram of how the control lines are being lead below deck on Constellation, and where they penetrate the deck to go aloft. This doesn't show the tacks and sheets of the coarses as yet.

con_brace_routing.jpg


Pictures on the ships under way and contact information

http://todd.mainecav.org/model/.

Where the Winds Blow

Mark Steele of Melbourne Australia wrote a column for Duckworks online magazine called, Where the Winds Blow, about model boats and model boat sailing. Mark died back in March 2014. In July I took over the column. The most recent edition is at http://www.duckworksmagazine.com/14/columns/wtwb/index.htm.