Short video about building wooden Star45 radio controlled sailing model
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The Star 45 is a one design class of model yachts

PondYachtworks in Scottsdale, AZ.
American Model Yachting Association Star 45 Class

The Star 45 is a one design class of model yachts recognized by the American Model Yacht Association. This boat is 45" long with a minumum weight of 12 pounds. The design is a semiscale model of a International Star. These boats can be scratchbuilt, from a kit or purchased complete.

What about keel shapes and keel-bulb design

The Star 45 R/C Model Sail Boat - Builders Journal

"Dave Mainwaring"
Someone asked about shapes and sizes.

I like keels that resemble in some manner the "Scheel Keel". Flat bottoms help fight heeling. My version was based on my sailing in waters with lilies and pond grass that snagged torpedo shaped bulbs. I liked being able to back away and have the crap slide off the keel.

Here is a photo of the original Mainwaring Keel and Mainwaring Bulb

S45 Rigging Bill of Material from John Fisher

Building Displaying Sailing
Model Boats and Ships

S45 sail boat Rigging Bill of Material from John Fisher
From: 'J Fisher'
Date: Wed, 3 Jan 2007 21:02:38 -0700 (Mountain Standard Time)
Subject: Re: [Star45] Deck rigging and such

Here is the list on the star 45 yahoo groups for rigging. I am using the following for my next couple of builds:
GBMY item #, description, qty, purpose
019, 3/8' alloy tube, 1, Jib boom
034, Hales single block, 2, main and jib sheets
146, tapered drain plug, 1, plug in transom
182, Z sheet hook, 2, sheet ends/boom attachment
202, large bowsie, 1, back stay/forestay with 80 lb Dacron, order small ones if using spektra
206, O-rings, 1, hold the Z hooks to the boom.
254, double block, 2, main sheet and jib sheet adjuster
255, sheet exit, 1, turning block for main sheet from under deck to above deck.
269, eye plate, 1, mounting for jib block.
272, 180 deg sheet lead, 1, turn around for jib tweaker
280, sheet hook, 1, hooks for backstay and fore stay.
282, tang, 1, attach lowers to mast.
907, rigging screw, 4 hooks, 2 packs, upper and lowers to the deck.

I also build my own chain plates, so I don't order them from GBMY. Don does carry them if you need them. I also like the Ludwig mast better than the bantock mast, so I ordered 8 foot masts cut to 69' from Larry Ludwig, the other 28' or so is the main boom. Last time I made all my own boom vang, mast fitting. This time I ordered them from Larry. You can use the bantock mast, boom, and fittings from GBMY as well. They are good stuff and I have them on my IOM.

The back stay crane is made from 1/16 (.063') aluminum that I bought at the local hobby shop.
John Fisher
photo's courtesy of "Larry Ludwig" at, Ludwig Mfg.


Star45 What is a hull ? Dave's construction categories, unofficial

Model Sail Boat Building, How To Build A Wooden Star45 R/C Sailing Model: What is a hull ? and construction categories
A composite hull:
a hull constructed of wood and covered with reinforced plastic (cloth impregnated with resin).

a hull constructed using a laminate (sandwich) consisting of reinforced plastic (cloth impregnated with resin) on two sides of a core . Core materials may be foam or wood.


Jib booms, radial jib fittings and vangs

The mainsail and jib on the Star 45 are self tending. That is they can swing from side to side as the model tacks without requiring the sheets to be tended.

Originally on the old model the jib was loose footed and did not use a jib boom (aka a jib club). The addition of a jib club allowed the jib shape to be controlled.

Like the main sail the foot of the jib will fly up is some type of vang is not in place. Typically a swivel is placed along the forward end of the jib boom and clipped to a deck fitting (aka jib rack).

Look at the jib as a triangle. The halyard pulling the head of the jib places a force on the jib swivel. As the swivel is moved forward and aft along the jib boom the leach of the sail has more or less ability to rise. The head of the jib also moves off center.

It is possible to find jib boom fittings that anchor the forward end of the jib to the bow and use a vang to control the lift of the boom. These are known as radial jib fittings. The jib stay attaches to the radial fitting. This has the advantage of staying taught against the back stay as the sails are trimmed,

The jib boom and swivel also pull against the back stay. Since the jib stay attached to the jib boom in this arrangement moves off center and is subject to varying wind forces the tension on the jib stay and back stay will vary.

The driving force of the sails is changed when the slot between the mast and jib changes. Finding the best spot for the mast and jib swivel/radial fitting adds the challange of setting up the sails prior to sailing.


Jib Tweaker VS Jib Twitcher

The Star 45 R/C Model Sail Boat - Builders Journal
A Jib Tweaker adjusts the length of the jib sheet.
A Jib Twitcher pulls the job boom wing on wing while sailing  down wind
Drum Servo with Jib Tweaker from Dave Ramos To:
Sent: Fri, 14 Nov 2008 10:23 am

The following photos show my set up for a drum servo and jib tweaker.

Hope this helps David Ramos, Chesapeake Performance Models
227 Main Street, Stevensville, MD 21666
From Dave M.

 Jib Twitcher:


Wood choices and AMYA rules for Star45 Class

Hulls may be planked using any number of types of wood, including thin aircraft plywood, cedar, balsa, etc.

The Star 45 is a terrific boat for sport sailing and family fun. If you want to race other Star 45's you should build to the AMYA Class rules.

Here are key 2006 AMYA Star 45 Class Rules,section 1.0 Hull:

1.1 The Star 45 Class establishes as their approved plans a set of lines and drawings as the approved reference and construction plans for the class. These plans are scaled and appropriately modified for the use of modelers building a 45-inch model of the Star Boat. Existing plans supplied by kit manufacturers, etc. are grandfathered. New molds, plugs and scratch built models shall conform to the approved plans and specifications.

1.2 Hull length will be 45 inches (plus or minus one half (1/2) inch overall. (NOTE: this does not include any chain plate for backstay attachment, or 1/4 inch bow bumper if used. However, if the chain plate is attached to the transom or overhangs the transom, it may not extend beyond the transom more than 3/8 of a inch.) Hulls may not be less than 11 inches nor exceed 12 inches in beam when measured at the widest point on the deck. (Rubrails are not included in measuring but will not exceed 1/4 inch of thickness/width.)

1.3 In the event of a builder choosing to scratch or hand build a Star 45 Yacht, the builder must adhere to the class approved reference and construction drawings, as obtained from the AMYA Ships Store, as in the builders ability. A second consideration in scratch building is to ensure that safe and sound building practice be maintained.

1.4 All hulls will be constructed of wood or fiberglass or a combination of wood and fiberglass and be a minimum of 16 ounces when weighed before attachment of the deck and keel. This weight must be verified by another member of the Star 45 Class using the Class Measurement Form.

1.5 Decks shall be constructed of wood, fiberglass or plastic laminate material.

1.6 All hulls shall be the standard hard-chine hull. Hulls may be built with a sheer at scale height or with a sheer no more than one inch higher than scale (when measured at the point of maximum depth of sheer.)

1.7 All fiberglass and wood hulls will have a name plate permanently attached to the inside of the hull so as to be seen when the hatch cover is removed.

1.8 At or before its first Sanctioned Regatta the newly built model yacht must be measured using, as reference, the approved measurement form and signed by not less than the owner of the model yacht and one other member of the class. This measurement form shall become, with the registration card, a permanent record of this model yacht.

1.9 The AMYA Star 45 Class recognizes and approves the molds and manufacturer and/or kit packagers of Star 45 molded hulls and kits in existence at the time of approval of these specifications. These sources will be approved sources for the class. New manufacturers will be directed to submit the first of their product to the Class Secretary for approval.

1.10 No maximum weight is specified, however, no yacht will weigh less than 12 pounds when fully rigged ready to sail. This means with all gear, rigging, sails, radio components, batteries and ballast placed and secured on board.

1.11 Bow Bumpers are mandatory for all class registered STAR 45 yachts. Bow bumpers are limited to three eight's of an inch (3/8") overhang. Bow bumpers shall be excluded in the overall length measurement, whether recessed in or otherwise attached to the bow stem. Bow bumpers must be of resilient fabrication to minimize damage to another yacht in the event of a collision.


Lester Gilbert on sail making for model sail boats

Model Boat journal

Lester Gilbert on understanding of sail making for model sail boats
Lester Gilbert wrote:
For anyone interested in sailmaking, I've just finished editing Larry Robinson's "Making Model Yacht Sails" (part 1 only) booklet and have published it as an "international" edition. I've done this, not to get rich ('cos this isn't going to happen to either me or Larry or anyone else connected with this enterprise!), but because I've spoken to a lot of sailors who want to make sails but don't know the "right" techniques, and who are being misled by incorrect accounts of how this might be done.

A sail block

(Illustration from Larry Robinson's "Making Model Yacht Sails")

From my understanding of sail making, there are two ideas I want to contradict.

The first idea is that you can make sails by accurately cutting a curve on a panel, and then attaching it (stitching, gluing) to another panel. Well, while you might be able to cut a good curve some of the time, your fingers just don't have laser accuracy in them to stick A to B and you'll hardly ever obtain reproducible or reliable results. (It might be possible to butt-join the curved edge to another curved edge with a little more reliability, but this doesn't yield what the Equipment Rules of Sailing define to be a seam. Such a sail couldn't be used in sanctioned IOM competition, though it would be OK in a development class.)

The second idea is that you can drape your panels over a "camber board" and get a nice shape that way. Well, let me be clear about what I'm knocking here. I take a "camber board" to be a length of curved surface, where the curve is like the surface of a cylinder. In this case, your panelled sail will have exactly the same shape as a single un-panelled sail and, if you wanted a three-dimensional shape, you've wasted your time (though the result certainly looks the part).

Larry's booklet is the only source I know which carefully explains the use and construction of a sail block. I am sure that this is really the only way (in your garage, please, not in some specialist workshop!) to make professional sails, to obtain reliable and reproducible three-dimensional shaping, and to be able to tweak and change your shaping as you learn about the whole business.

(Warning: Y'all should know I have ten thumbs and have never made a sail yet. What I have done carefully is to watch and talk to those who do, both professionally and as home builders, and measure the results. Making Larry's booklet available internationally is my way of telling you what I've learned.)

Bob Wells will be able to ship this within the USA, and I expect that it will also be available from Don Ginthner at GBMY. For worldwide sales, contact SAILSetc. Bob Wells' e-mail is "bob" at "", GBMY is "rcsailing" at "", and SAILSetc can be contacted through "sales" at "".

I've attempted an analysis of how blocks work on a new page, Sail blocks analysis, and have a new spreadsheet there to help.