Building a MM – Micro Magic V2 Almost-Ready-to-Sail Assembly Guidance

Introduction 1 (merge with Intro 2)

This post explains the building of a Micro Magic almost-ready-to-race model yacht.

The contents of this introduction will be merged with Introduction 2 when this post is completed.

Assembling a Graupner V2 almost-ready-to-race (ARTR) Micro Magic model yacht is a reasonably straight forward project for those who have built model yachts in the past. “Non-modelers” may be a challenged – but it is certainly doable. PMYC members have access to other members who have building experience.

 The Graupner MM Manual makes the point “This item is not a toy. …. Assembly…. must be performed by experienced modelers….”  I think Graupner is overstating the matter. That said, the detail in the Manual is sparse — I think that’s an understatement.
This post has two perspectives. One is what I have named “Casual Sailing”.  The other is “Racing”. The Casual Sailing topics are, essentially, a reflection of the Graupner instructions. The goal is to get a boat in the water and sailing. The Racing topics modify the Casual Sailing procedures to reflect modifications that will make the boat easier to sail and go faster in a race. The post is not consistent throughout on this dividing because the idea evolved while assembly was underway.
My immediate focus is to complete the assembly and the Casual Sailing instructions. Upon completion of the Casual Sailing instructions I will return to the Racing info.
The Racing sections will be focused on the changes to the Casual Sailing instructions. Those changes will have to be modified by the input one receives by studying the several articles covering the building of a Micro Magic from a kit and the creation of a fast racing Micro Magic.
This post has become larger than I anticipated at the beginning. I am noticing that it is loading a bit slowly. I am going to divide it into multiple posts with an appropriate indexing at the beginning of the first piece.

The boat assembly and the Post content development are ongoing.

Please read these next few paragraphs (July 2017)

I am documenting the assembly of the boat as I do the assembly. So, if you are thinking about or already committed to the assembly of an MM ARTR, come back regularly. I don’t spend all of my time on this assembly or writing. So, the assembly project that I estimate will take most people 10 – 15 hours may extend over  weeks for me.

You may find this tedious reading. However, I assure you, that if you have to figure all of this out as I have done you will feel like you are building the kit from scratch — another challenging project. Be patient and work through the steps. The labor savings and resulting build quality will be worth it.

Call me (520-461-6473) if you want to discuss the topic. Or, email me.


Introduction 2 (merge with Intro 1)

This will be the beginning of the Post when the boat is completed

Mid-June, 2017, the Pima Micro Yacht Club purchased two Graupner SA  MM ARTR (Almost-Ready-to-Race) boats. These boats are constructed by the manufacturer needing only final assembly. The idea for PMYC to buy a kit  was a hedge against a repeat shortage of MM’s experienced this year and to make it possible for persons new to the Club to easily obtain a boat that they could be sailing  relatively quickly.

The Graupner SA instructions are minimal. So, I decided to assemble the PMYC-purchased boat. And, will sell it when the boat and documentation is done. The focus of the build is  lot of research is going into this build. My sources are the multiple writings of MM gurus. The more significant of those writings are listed in the References Section below. I strongly recommending looking at all of them. My writings have drawn heavily on the content of these documents plus my experience as a model yacht builder going back to 2010.

The Manual notably lacks details and what information is there can be difficult to interpret unless you can examine a finished boat. This Post supplements the Manual, providing the desperately needed detail. It contains two perspectives on the assembly. One, to build the boat by the instruction (vague as they are). I label these sections “Casual Sailing”. This is a boat that can be assembled rather quickly and will make for a fine casual sailing experience. The second perspective is racing. I label these sections “Racing”.  This is the same boat but with multiple extra and sometimes time consuming steps, but will result in a boat that will be capable of being competitive – within the range of your boat handling skills and racing expertise. If you only interest is the casual sailing then use the label info. only.

As I said above, the focus of this post is primarily to help non-modelers. I have tried to give the guidance in a way that requires the least amount of purchases of tools and materials. If you are a modeler and/or have many, many tools, use the guidance to help yourself pick out the right tool or a better material based upon your experience.

Beyond the contents of this Post you can ask PMYC members for advice. And, be sure to look carefully at other boats for fitting-out ideas. A particularly good source is Jerry Robertson, Bill Brown and myself.

The emails for these PMYC members are:

A link to this Post is on the menu at the top of each page on the website (Assemble a MM V2 ARTR) so you can easily find it. It will be updated as I go along with pictures and narrative. As I am writing and assembling, I am thinking about assembling a package of “stuff” (I don’t really know what that might fully mean at the moment) that could be purchased along with the boat to make the assembly easier — removing most of the need to make yet another run to the hardware store.


Remember to read the Summer 2017, #188, issue of Model Yachting magazine. Several articles appear there that are of particular help in the assembly project. This issue of Model Yachting is a must have if you are to be a Micro Magic racer. Or, you can read the articles on our website.

In the writing, references to Mike Eades or Greg Norris are references to these two documents. Otherwise, I will identify any alternative source associated with these two gentlemen.

If you do not receive Model Yachting magazine, please support model yachting in America by joining the American Model Yachting Association. It costs $35 annually ($5 fee for the first year). The magazine is worth the price.

Here are two more highly relevant links for Micro Magic sailing:

A Caveat

I am not a professional writer. I am a fast typist. In my case that can lead to spelling errors, (finger movement errors). I proof read my writings regularly and my wife does some proof reading. But, after that I know that some grammar errors escape detection. I hope you will be tolerant. The key question I regularly ask myself is “Does it communicate?”. If the answer is “Yes”, then I have done my job reasonably well. If you would like to comment or add to the narrative, please Leave a Reply at the end of the Post. When I finish the project, I plan to spend more time on editing the material and adding more images.

Materials Needed In Addition to the Box Contents

The following is a list of items, in addition to those in the box, that you will need to do the assembly — prices are approximate where given. For my own convenience, I looked up item prices on the Internet. So, the numbers I give may be a bit low compared to local stores. For what I want to accomplish here they are good enough.

  • Stand Assembly
    • two wood blocks (2″ x 6″) to stabilize the stand-ends during assembly – get them at your local hardware or lumber store for free from their castoffs. – $0
    • Thin CA (3 sec. set) – $6.
    • Thick CA (30 sec. set) – $5. (Note: when using thick CA, you can instantly make it set by sprinkling Baking Soda on it. It makes the surface rough but does the job.)
    • Wood screws size: xx phillips head (for securing the stand ends to the wood blocks during assembly)

      Carpenters Framing Square – 8″ x 12″
    • Varnish or paint to protect wood – optional (krylon Clear Interior/Exterior spray – $5.)
    • A simple carpenters framing square 8″ x 12″ (See pic on right) – $5 – borrow it if you don’t have one
    • Drill to drill holes in the ends so that they can be stabilized during assembly.
    • Phillips screwdriver – borrow it if you don’t have one
  • Hull
    • Sheets – Tufline XP 15# – replaces the lines that come with the kit.
    • A small amount of 1 mm plastic sheeting to build a mounting platform for hte screw eye for the jib sheet. See the xxx figure.
  • Rudder
    • Allen keys (hex wrenches) – 1.5mm and 2.5mm. If you do not have a set of these keys, you can buy them at Ace for about $1.00 each.
  • Sails
    • Sail Tape or Sail Patch Tape – approx. $23 for 3″ x 15′, enough to strengthen the luff of the MM sails for 60 boats (3″ x 3″ piece). This could be part of a “PMYC MM Building Package” NOTE: I have enough to support the build of a dozen boats.
    • Sail Numbering Tools. I have access to my wife’s quilters cutting mat and transparent grid tool. It made the number application process easier. If someone in your household does quilting your have an immediate leg up on the sail application process.  Check around your neighborhood for a quilter. For reference the two products shown are made by Creative Grid and Crafty World (look them up on the Internet). The grid is 6″ x 12″ and the mat is 24″ x 18″. The mat is a bit pricey for this one project. So, the same carpenters square identified above would work as well. Use the grid that is in the sail material to help align the numbers.
Crafty World Quilters Cutting Mat
Crafty World Quilters Cutting Mat
Creative Grid






What’s in the Box?

Pieces & Parts

The Manual – four languages
The Box
Outstanding Paint Job. Notice the glare on the hull.
Rudder and Keel Spacers
Keel and Keel Bulb. The Keel has to be shortened a bit for racing. I’ll come back on this when I install the keel.
This is what you will see when you remove the box cover.
Rudder push rod and rudder post installed
Mast positioner and Jib sheet exit .
Sail sheets – ready to go


Micro Magic ARTR interior - everything is installed
Servos, sail servo arm, rudder push rod and power switch – already mounted. Interior is very neat and clean.
Servos, sail servo arm, rudder push rod and power switch – already mounted

Hull and More are Already Assembled

The hull, mast and keel com  completely assembled.  This is a step that allows you to skip about 10 hours of build time compared to building the kit. The completed items include:

  • The sail and rudder servo platforms are in place and the sail and rudder servos are installed and the arm connecting the rudder servo to the rudder in the cock pit is installed.
  • Keel box is in place
  • All deck fittings are installed
  • Deck is glued to hull
  • Rudder tube extending from the bottom of the hull to the top of the deck are installed
  • The keel is assembled
  • The sail sheets are installed. Note: the sheets are replaced for racing — and that I did change them in accordance with the Racing section below.
  • The mast and boom are assembled, including stays and jib topping lift
  • The sail and rudder servo arms are installed
  • the boot for the rudder push rod is in place
  • The rudder servo to rudder push rod is installed
  • Hull and deck are painted – and the job was well done
  • The sheets are in place. The jib sheet routing in the boat was changed. See Jib Sheets section below.

Note: you must provide the receiver and battery. This will be covered further along in this post.

First Impressions

My first impression upon opening the box is that Graupner does an outstanding job of providing a ready-to-sail product. Everything in the box was secured and neatly arranged. There were multiple packets of parts. The most impressive part of the package was the hull. It has a gleaming white painted finish that was obviously done by someone with a paint gun and skilled; not a spray can. The finish is smooth and dust-free. It was not until a few days after I opened the box that I removed the canopy. I was surprised at the neatness of the interior installation which included the servos and the power switch. If one does not particularly care to build a boat this is a great solution.

If you want to see the boat I have let me know. Unless you are strongly motivated to build, this is an excellent way to get into MM sailing.

Jerry Robertson and I agree that this boat is more fun to sail than the Victoria.

How Long Does it Take to Complete the Job?

I will do my best to keep track of the time to get this project done – not including the writing.

  • Build stand – 1 1/2 hours including applying a coat of varnish/paint followed by a light sanding to smooth the post-paint rough grain.
  • Install rudder – 1/2 hr.
  • Install keel – 1 hr.

MM Class Measurements

The items in the list reference the Class rules paragraph number. Link to MM class rules:

Micro Magic Measurements

Item Rule This Boat
2.1 – Minimum weight of sail ready boat 860 gm
3.2 – Axis of rudder from inner back-side of keelbox =210 mm  205 mm
3.4 – Bottom of lead ballast to the hull <=135 mm 137+ mm
3.9 – Leading edge of keel to front tip of bulb => 25 mm  38 mm
3.10 – Weight of the keel assembly including spacers 380-420 gm  415 gm
4.10 – distance from the deck to top of mast <=780 mm
 4.12 – Middle of mast-positioning slot to the jib boom deck connection  =176 mm  176 mm
 Mast diameter  5-7 mm  5/6 mm*
 Boom diameter  >=4 mm  4 mm
 * Top and bottom of mast are 5mm, center is 6mm.

Note: The MM V2 ARTR boat may not adhere exactly to the Class Rules.  See Blue items in table above. The following paragraph is from the Micro Magic Class Rules: (Jerry: that’s the boat in this article)

From: Micro Magic Class Rule – 2017

Recommendation concerning the Ready To Race (RTR) boats.
These boats, entirely built by Graupner, like the Graupner 2014.HOTT or RFH (Ready For Hott Version), may not be 100% class-conform. Their keel may be a little too long and slightly overweight. Also the position of the jib and rudder may be different a little bit.
Nevertheless the organizers of a Micro Magic Regatta are advised to accept these boats to participate for the time being. This is very important for the growth of the class. Exclusion of these boats could mean that new MM-sailors with such a boat are not allowed to race, and this is undesirable.
July 2017 – Since this addition to the rules was made the manufacturing has been moved to China. The Chinese boats will be available in the USA in mid-August (Graupner estimate in June 2017).


Step 1 – Assemble the Stand (MM 7)

Assembling the stand was one of the more frustrating task I

Stand showing the wood blocks and carpenters square in place
Stand showing the wood blocks and carpenters square in place

have executed in a long time. It was not until I had moved well along with the assembly when I realized that the cross planks connecting the ends are all

slightly warped. I’m sure that there is an easy solution but I don’t know what it is. Maybe Jim Haines can improve this section when he builds his boat. So, the challenge is to either find a way to strap it all together before you glue or fight the twisting or make new pieces. Not knowing another way I chose to fight.

I used small wood screws to attach the stand-ends to the wood blocks to temporarily stabilize them while I worked. Then one at a time I added the cross pieces fastening them with Thin CA. After I completed the assembly I removed the screws then went back to the joints with the Thick CA. With four slightly twisted cross pieces, the resulting assembly was inevitably also twisted. The good news is that the boat on the stand puts all four corners down on the table. so, in the end, it’s not a big deal.

Finally I put a coat of clear finish on the stand to protect it from moisture. That process caused the wood grain to rise. But, a light sanding with fine sandpaper made smooth surfaces.

After assembly, put the black thin strips with the sticky back on the tops of the end pieces to serve as a smooth surface for the hull to rest on. I found that one piece served both ends. So, I have a replacement piece. The challenge will be keeping track of it over time.

Here is a Comment submitted about the stand on July 1.

The wood stand issue that Jerry Walker points out here may be common to many MM boats either in either kit or ARTR form. I opened my own ARTR package only to find that two of the horizontal plywood braces for the stand were in bad shape. The braces are made of a thin (0.5mm) solid wood core with a single layer of nearly paper thin wood laminate on each side. The laminate on one side of each brace was delaminated nearly completely from the core. I attempted to re-glue the laminate to the core but it ended up a floppy, twisted mess. I would suggest buying a sheet of plywood at the hobby shop and making your own sturdy braces to replace the faulty Graupner parts. Don’t waste your time on re-gluing.

The wood stand issue that Jerry Walker points out here may be common to many MM boats either in either kit or ARTR form. I opened my own ARTR package only to find that two of the horizontal plywood braces for the stand were in bad shape. The braces are made of a thin (0.5mm) solid wood core with a single layer of nearly paper thin wood laminate on each side. The laminate on one side of each brace was delaminated nearly completely from the core. I attempted to re-glue the laminate to the core but it ended up a floppy, twisted mess. I would suggest buying a sheet of plywood at the hobby shop and making your own sturdy braces to replace the faulty Graupner parts. Don’t waste your time on re-gluing.

Step 2 – Hull

This step does not have an equivalent in the Manual. It is included here because, for racing, a change is appropriate.

Casual Sailing

Battery Strip




Mike Eades recommends changing the main and jib sheet materials. Mike recommends a 50# test line. I recommend the 15# TufLine XP line. A spool contains 300 yards, enough to do more than a few boats. I have used this product on two Victoria models for three years without visible wear or breakage. A big benefit of this product is its high flexibility. The sail positioning will never be influenced by a stiffness in the sheets.

It is easier to make this change now as it will be tedious once the mast is on.

Make the new sheets the same length as the original and reuse the bowsies. (Jim Haines is experimenting with a smaller bowsie. This post will be updated to reflect his experience.)

For this project I changed the sheets.

Jib Sheet Routing

Note the orange rectangle in the center of the figure. The color is to draw attention to the area. A 1/8″ screw eye was embedded in a piece of plastic cut out of the unused keel spacers. I made a groove on one side of the piece, put the screw eye threads into it and cemented it to hte vertical piece shown in the figure. This screw eye serves as a turning point for the sheet coming off of the servo arm and makes its way to the cockpit and a bowsie adjustment. The line running from the screw eye through the photo date in the lower right corner is the sheet going to the cockpit.

hhfghfg fig. of drawing

Figure xx. Routing of jib sheet from bowsie adjustment in cockpit to the jib. See the nearby figure for detail about the screw eye turning point on the keel box.

Remember those extra keel spacers? we have a use for a piece of one of them.

Step 2a – Install the Rudder (MM 8)

Casual Sailing


The instructions, Page 8-20 are a little hard to follow. But, it is just three parts; the rudder, a spring and the arm. The push rod post has already been added to the rudder arm — see the right side of the page near the Allen key for this assembly. You will need a 1.5 mm and a 2.5 mm keys in the future to make adjustments to the boat. If you do not have the two Allen key sizes: 1.5 mm and 2.5 mm, you can get a set of metric keys at Ace, making sure that the two sizes ares included. You will need these two keys in the future to make adjustments to the boat. The 1.5 mm key also fits the post on the rudder servo arm in the boat.

The rudder shaft is steel and will rust. Simply use petroleum jelly to grease it. And, periodically, remove the rudder, clean the shaft with steel wool or kitchen cleanser and replace it, renewing the grease. I am not going to lube the shaft until the end, in case I have to remove the rudder during the rest of the boat assembly.

Connecting the Servo and Rudder Arm

The positioning of the rudder push rod oat the two ends needs a bit of explaining. (See Rudder/servo connection image . Notice that the connector on the servo end of the rod is in the last hole. The connection is on the inner hold on the rudder end.

Rudder/rudder servo connection. Use outer hole on servo end, inner hole on rudder. The hole will have to be enlarged a bit to accommodate the post. The rudder arm is not tightly attached. See the text about the solution.

If you do not use these two hole positions you will find that the rudder arc is narrow and that the boat does not turn easily. If you have a transmitter with a Travel Adjust setting, then also adjust the travel so that you get about a 45 degree travel on each side of neutral. If you do not know how to make setup changes on your radio contact a local hobby shop (In Tucson contact Hobby Town on E. Speedway.). As a last resort, read the transmitter manual.

See the next section for dealing with the hole in the rudder-end control arm.

Rudder arm post not secure on my boat

In the process of moving the connector post to the inner hole in the rudder control arm, I noted that the threaded lock nut fitting on the underside of the connector on the rudder arm was not tight – and could not be tightened without binding. Worse, the nut could not be threaded on far enough to engage the locking portion of nut. My solution was to drill out a small indent in the bottom of the arm – enough to allow the lock nut to engage the threaded post. Be very careful with the drilling. The bit tends to bind in the soft material of the arm and could go all the way thru – then time for a new arm.


a. Rudder Tube Protruding from bottom of Hull

I ground down the metal rudder tube protruding below the hull so that the rudder fit closer to the hull. You may have to shave the top edge of the rudder slightly to make it fit the hull shape.

Step 3 – RC Transmitter/Receiver

a. Transmitter

If you already have an RC transmitter, you are likely not interested in this section. If you do not then keep it simple by looking around for a used transmitter – Spektrum’s DX6i’s or later are easy to find and cost under $100. Or you can obtain a new HobbyKing Orange Transmitter for about $65.

You can view  this radio at the HobbyKing website.

HobbyKing DSM2 Orange Transmitter.

b. Receiver

Used rc receivers are more difficult to find. but, no worry. You can purchase a HobbyKing Orange R610V2 DSM2 6 channel receiver for under $10.

You can view this receiver on the HobbyKing site.

HobbyKing OrangeRx R610V2 Lite DSM2 Compatible 6CH 2.4GHz Receiver w/CPPM

c. Battery

AA Battery Pak(comes with the boat) – comes with the boat. Adding replaceable Duracell AA batteries yields a weight of 110 gm.

The simplest battery solution is to use the AA battery pak that comes in the MM box. You can use Duracell Alkaline AA batteries that can be found everywhere. Don’t forget to check out Costco’s for their own label or the Duracell’s. Their prices are usually lower than anywhere else. Simple (non-rechargeable) batteries will power the boat for at least a dozen outings of 2 or 3 hours each. The Duracell AA battery at Costco has the part number MN1500. My estimate is that this is a 1500 mah battery; plenty for the MM.

You can also use rechargeable NiMH AA batteries with the battery pak. Of course, you will need a charger. Talk to other sailors about this topic. It’s too much to cover here.

If you want to lower the weight you can use a

800 mah AA 5-Pak – powers the boat for, at least, several 3-hour outings. Weighs 64 gm.

rechargeable AAA NiMH battery pak of about 800 mah obtained on the Internet or from Batteries Plus. This will get you multiple several hour outings on the pond. The 5-cell pak, shown in the nearby figure, is charged weekly after 3 hours on the pond in about 10 minutes at a 1 amp charge rate.

You can get an even lower weight by using a LIPO. rechargeable pak. The weight of a 7 V Battery is about 57 gm.

Step 3a – Install the Boat Receiver and Test

Casual Sailing

The receiver



Set the Travel Adjust on your Transmitter for the Aileron Channel to give you a 90 degree rudder travel.


Step 4 – Install the Keel (MM 9)

The MM instructions, Page 9-20, do not identify the spacers needed for keel installation.   You will use the narrow spacers. Discard the wide ones.

The keel fits very tightly inside the keel trunk. The first step is to sand the keel box a bit with particular emphasis on the immediate opening at the hull. It appears that paint has gotten inside. Also sand the keel insert until the fit is snug but not tight. Never force it in, as this could blow the keel box apart, and that is a very difficult repair.

Use a 1/8″ drill bit to open the deck hole a little to allow passage of the screw. There was paint in it making it a bit too small for the screw on the top of the keel.

The keel will be centered in the slot. This means that only the narrower of the spacers will be used, one on each

Keel insert with standard narrow spacers and extra spacer new keel
Keel insert with standard narrow spacers and extra spacer new keel

end of the keel insert. See Fig xx. Retain the wide spacers for possible use elsewhere. Sand the spacers to remove the mold marks. Glue both in place with CA glue. Note the length difference.  This build concluded here with the keel able to rotate fore and aft. by about 3/16″ pivoting on the screw at the deck. No good. I added a 1″ long spacer on the aft side of the insert approximately 3 mm thick (fore and aft).  The keel fits snugly now. The screw prevents motion at the deck. Note the image showing the keel with the box spacers and the additional one immediately above the keel fin.

Insert the keel into the trunk until it won’t go further. Move it back and forth until the screw comes out of the hole. The screw will be sticking out of the deck by about a 1/4″.  Put the washer and nut on the screw sticking out of the deck and finger tighten it.

Notice that the forward edge of the keel is recessed in the hull by about 2 mm. That is expected with the MM.

The keel is installed. The topic of the angle of the keel bulb to the water line will be revisited at the end of this post. Meanwhile its time to move on.

Step 5 – Check the Alignment of the Keel and Rudder

Casual Sailing

Any misalignment of the rudder and keel is of no consequence.


At this point in our assembly, you can check the alignment by putting the boat on the stand and then sighting between the keel and the rudder. This boat’s keel and rudder are slightly out of alignment. Note: my own MM, #180 has the same condition — built from a kit. The is an item that needs to be investigated with the MM gurus. I put it on the Finalizing Items list at the end of the post.

Step 6 – Prep the Sails

Casual Sailing

The jib is ready to install on the boat. The main sail has holes in luff for the metal rings. Install the rings – with the exception of the top one (the top ring is above the jib mount fitting on the mast). For consistency place all of the rings in the same direction. With the rings installed you can insert the mast into the rings. Add the top ring. See the Racing section for another aspect of the ring placement.

Adding sail numbers and your home country are your choice. If you want the numbers, see the Racing notes below.


Main sail attachment points


Add numbers and country letters

Having numbers on your sails is mandatory for participation in racing. However, for Club racing (only our own members) though numbers are mandatory you are not required to register your boat. Usually, any unique number among those in the local fleet is acceptable. That said, I strongly recommend registering your boat with the Micro Magic Class. By doing so you are supporting the work of the Class.

So, register your boat and put the sail number on the sail. Putting your numbers on the sail before it is on the mast is much easier than after it is on the boat. Get your sail number by contacting the Micro Magic Class Secretary. Send your sail number request to  The sail numbers are three digits. You can request a specific number though there is no guarantee of its availability. Ask for several numbers. Or, in my case, I asked for a number with sevens and ones. I got #717. This is a number that is easy to put on the sail. You can pay by check or PayPal (perhaps some credit cards).

Putting the numbers on the sail is tedious but not difficult. The greatest challenge is to end up with the numbers evenly spaced and more or less parallel to the water. See the Figure of my sails. I will give the dimensions I used for your convenience.

Number and country positioning on the sails
Number and country approximate positioning on the sails
Jib with numbers near foot of sail
Main Sail with numbers near middle of sail. USA letters not on yet.
Example – Sail and numbers template taped to cutting board. Use Sharpie to draw the numbers on the sails

Now for the number positioning on the sails. The size of the numbers and letters on the sails are specified in the “Locating The Numbers on the Sail” in the Reference Section near the top of this Post. The document referenced provides an exact size template for the required lettering, the MM logo and the numbers 0 – 9. The MM Class rules do not address the detailed placement of the sail numbers on the sail.

The MM Class Rules state:

The mainsail must display a class provided sail number and country designation…. Letters and numbers should be of a good contrasting color and completely filled in.

It is conventional to place the numbers on the starboard side of the sail above those on the port side.  The placement of hte numbers is identified in the “Locating The Numbers on the Sail” link in the Reference Section near the top of this Post.

Noting the comments in Greg’s article, I measured the above-deck part of the mast. It is about 28 5/8 “. With the boom and mast installed on the boat the distance between the top of the boom and the bottom of the mast head crane is 5/8”.

Step 7 – Mast & Main Sail

Remove the two pieces of tape from the mast. We’ll sort out the use of the strings later.

The total mast length is 31 7/8″.

Casual Sailing

a. Mast

Jib (short sting connects to the top of the jib), fore stay string (attaches to the deck at the frront of the boat.), topping lift (attaches to the aft end of the jib boom.

The three mast pieces have been connected (above the jib attachment point and the bottom 2″ of mast)  and the mast head crane and jib/topping lift attachment point have been installed. The long string from the end of the mast head crane is the back stay. The long strings attached to the jib attachment point (the strings extending to the left of the mast) are the topping lift (string connects to the aft end of the jib boom) and the jib fore stay (string connects to the deck at the bow). The short string attached to the jib attachment point is the jib halyard — attaches to the top (head) of the jib sail.

b. Sail


Step 8 – Installing the Mast and Main Boom


Do you want to be a competitive sailboat racer?

Everything that has proceeded this section has been focused on getting your ARTR boat in the water. The details of making the boat as fast as possible are not addressed. This section addresses those topics that improve rules compliance or boat performance. THESE ARE NOT NEEDED UNLESS YOU ARE A SERIOUS RACER. If you are serious about the racing, you will likely be better off building your boat from a kit.

  • As you have already read in the Class Measurements section, the MM ARTR is not totally compliant with the class rules. Compliance with Rule 3.4 is straight forward. Shave the top of the keel insert to get the measurement in compliance. Establishing compliance with Rule 3.3 i. will require removal of the rudder tube and resetting it. That is not difficult but will require some redo on the construction and will be a bit tedious.
  • There is another matter that is important to MM performance. That is the angle of the keel to the surface of the water. When this keel was installed after the spacers had been inserted, the bulb was pointed downward by a couple of degrees. Greg Norris’ “Building a Micro Magic” article appearing in the Summer 2017 issue (#188) of Model Yachting and on this website (  addresses the topic of the preferred angle of the keel bulb relative to horizontal in the section titled “On to the keel fin and bulb and rudders”. In that section, it is desirable to have the front of the bulb angled upward between 0 and 3 degrees. Given that the keel on this current boat is already built we cannot exactly follow Greg’s instructions. My approach to assessing (and fixing) the bulb tilt are presented in the “Bulb Tilt” section at the end of this post.
  • Wet sand the hull using 400 and 600 grit wet or dry paper.

Keel Tilt

This section was referenced in the earlier “Install the Keel” section. The purpose of this section is to address the subject of the tilt of the keel bulb and to explain how the bulb tilt was estimated and what was done to correct it. (Its original tilt was front down. The desired is the front tilt up 0 – 3 degrees relative to the rear of the bulb.

I placed this section at the end because unless you want to participate in inter-club regattas this topic is not of great importance. For PMYC club racing any disadvantage it may represent could be offset by good sailing and racing skills against all but the fastest boats.

Before getting into the details I have included the words from an email I sent to Greg Norris along with his response.

June 30, 2017 Jerry wrote to Greg Norris:

In you’re Model Yachting article you state that the mark on the bow “…just above the round area at the bottom of the bow”. However, the picture appears to be showing the mark near the bottom of the round area. To me this is where the mark needs to be – at the water line at the bow. That is exactly where the water line on my boat is.

June 30, 2017 Greg responded:

So, in light to moderate air I place the battery so that the transom is just kissing the water at rest, and I now make my keels with the bulb cant at 2-3 degrees upwards, or 87-88 degrees as you likely measure it.

What is truly optimal in a MM is however unknown.  Optimal bulb cant in a towing tank with an IOM is 3 degrees, with 0-2 degrees being very similar, but anything over 3 degrees upward or any negative (downward) can’t being much worse.  I know of no testing in rc boats in waves or under actual sailing.


  1. Put keel in boat and gently tighten the nut.
  2. Put a pencil mark at the bottom of the round of the round area at the bottom of the bow.
  3. Put boat in stand on a smooth table.
  4. Position the boat on the stand until the distance between the mark on the hull and the table and the bottom of the center of the transom are equal.
  5. Measure the distance from the front and back tip of the keel bulb — the hypotenuse of a right triangle (130.5mm).
  6. Measure the distance from the front and rear tips of the bulb to the table.
  7. Subtract the two values. Hopefully, the front value will be larger than the rear. This is the Opposite side of a right triangle.
  8. Calculate the angles using a calculus calculator such as One angle will be approx. 88, the other 2. You want the larger angle to be between 87 and 90 degrees.

After all of this be sure to read Greg Norris’ Summer 2017, Model Yachting article. or, read it here:

Finalizing Items

  • Shorten the keel according to the manual on Page 9-20
  • lubricate the rudder shaft
  • Remove the text at the top of the doc.
  • Neaten up the images at the beginning of the doc
  • Snug up the keel nut.
  • Keel/rudder slightly out of alignment.

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