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Performance Modifications for the Thunder Tiger Victoria

by A. J. Moritz

ALL RIGHTS RESERVED, NO PART OF THIS DOCUMENT IS TO BE REPRODUCED IN ANY WAY OTHER THAN FOR PERSONAL USE, WITH PRIOR APPROVAL FROM MPI/MCI.
ALL MPI/MCI PATENTED DESIGNS, PRODUCTS, OR SYSTEMS EXCLUDING OEM SHALL NOT BE REPRODUCE FOR MASS PRODUCTION AND/OR RESALE. IT IS FOR INDIVIDUAL USE ONLY.

It is my belief that the Thunder Tiger Victoria and the Victor Model Products Soling 1 Meter are both excellent kit boats. Any AMYA club can use them to establish a new fleet.. These boats offer simplicity for new skippers who want to compete in true one design sailing but have minimal technical boat building skills.

The following methods and ideas for improving the performance of the Thunder Tiger Victoria are based on many sources and the author's personal experience. In most cases they can be applied to any R/C yacht class. One primary source for reference is Bob Wells' Manual for the East Coast 12-Meter and Optimizing the East Coast 12-Meter. These books are a must for every R/C skipper's library and can be purchased from Bob at 102431,3702@compuserve.com or 206-232-9036. In addition, Rod Carr has written informative articles on the Victoria, which were published in the July '96 and June '97 issues of RC Boat Modeler Magazine.

Below Deck Modifications

The recommended double purchase arm setup is based on the Futaba S-125 sail winch servo. The benefits of this system are as follows:

  1. Improved and precise control of sheeting
  2. Offsetting jib and main sail ratios
  3. Increased battery charge life cycle
  4. Better performance in heavy air sailing

I recommend using Nichido battery packs, and I prefer the 600 ma, 6.0 volt flat pack. This type of battery pack can be purchased from Tower Hobbies (#SANM007), or from any local R/C hobby store. A 6.0 volt NiCad flat pack weighs 3.9 oz. and should last most of the day. For the radio board, use the cut out mounting board that came with your Victoria kit. (rudder and sail winch servo mountings). But do not build the complete R/C mounting box, instead use two 1/4 inch sq. wood beams (spruce or basswood) to support the radio board inside the hull. (See Figure 1.)

At this point, do not epoxy the beams to the hull bilge sides. Do epoxy or screw mount the beams to the underside of the radio board. I prefer screw mounting so that the board can be removed if there is a problem with the servos or other electronics.

Figure 2 outlines arm fabrication. For blocks use either the PekABe single blocks (#515), or the KDH blocks (#K1391/19). Both are precision German-made blocks that incorporate ball bearings. Use of a block system is strongly recommended because it will significantly reduce line friction and increase battery life.

Mount the winch servo on the radio board and temporarily energize it via the receiver so that it can be operated when the transmitter is turned on. Go to a close hauled position and mount the arm assembly on the winch. In the close hauled position, the arm should be close to the centerline of the boat (bow to stern). Move the radio board assembly (board and beams), forward, until the end of the main sheet side of the winch arm has a minimum 1/4 clearance from the keel shaft pipe. When this clearance is established, glue the radio board beams to the bilge sides of the hull with 30 minute epoxy. To assure proper adhesion, make sure you rough up the area where the beams come in contact with the hull with sand paper.

For sheeting and all other rigging, I recommend using Spectra line. Spyderwire is a brand carried by Wal-Mart. Use a minimum 50 lb. test line. Smaller diameter line could get fouled in the block pulleys. Sheet routing is shown in Figure 3. The jib sheet is routed from the foredeck on the starboard side of the mast step and passes through a small diameter hole drilled next to the cleat. Use the through deck fitting from the kit that was originally intended for the Stern hatch cover (# BJ0126). Use the cleat located next to the aforementioned fitting for jib sheet travel adjustments. The jib sheet is then routed aft through the block on the jib side of the arm and back forward through the jib sheet deck fairlead to the jib club.

The main sheet is tied to a bowsie (adjuster) and looped through the shackle holding the block to the main side of the winch arm. After the bowsie is secured, route the main sheet through the eye screw (optional third block), which is attached at the cockpit bulkhead, bring the sheet back through its block on the winch arm and finally through the main sheet fairlead to the boom. The bowsie is used for main sheet travel adjustment.

Above Deck & Mast Rigging

The above deck rigging is a principal part of any class sailboat, full scale or model, and proper spar rigging is essential for high performance.

I recommend the use of alternative spars for your Victoria. The mast, main boom and jib club (spars), from the Victoria kit are heavy gauge aluminum. While the kit spars are of good quality, they are just too heavy. The main reason for using alternative spars is to minimize weight aloft.

Refer to Figure 4 for recommended mast rigging.

Spectra line is recommended for rigging your new spars. Spectra is considerably smaller in diameter line than Dacron or other equivalent lines. Therefore, to assure that the bowsie adjusters will not slip, use a minimum of 50 lb. test. There are different styles of spectra. The recommended type has a woven texture in lieu of a slick finish. The textured type is preferred because it lessens slippage.

Use the following sequence when tuning your new mast.

  1. Attach the forestay, and lower shrouds.
  2. Using a mast alignment device such as mast alignment calipers, balance the mast using the lower shroud adjustments. After the desired balance is achieved, attach the upper shrouds and snug them up equally.
  3. Site down the mast from the top. If the mast is untrue, make minor adjustments on the shrouds and backstay.
  4. Note the mast bend. There may be excessive bend due to backstay tension. To counter this bend adjust the tension on the jumper strut shrouds via the small sliding sleeve located on the top of the jumper shroud attachment point at the mast head. The goal is to keep tension on the jumper shrouds to generate the desired mast bend!

When tuned properly, lighter spars will help your Victoria to point higher due to the improved righting moment. In other words, due to the weight savings aloft the boat will be less tender when sailing up wind and, therefore, capable of pointing higher.

Four mast fittings are required; Mast head crane, jumper strut, spreaders, and boom gooseneck.

  1. The mast head crane can be fabricated from several types of material. Aluminum is preferred, carbon fiber is another good choice. Make sure when selecting a material type that you consider weight vs. strength ratios.
  2. Jumper struts are an essential part of the mast shape control. A basic jumper strut is shaped like a "Y" in which the trunk of the "Y" is inserted into the mast and the two arms are shroud guides.
  3. Spreaders can be fabricated from any lightweight material that assures strength. A preferred choice is a solid carbon rod with aluminum end cap guides for the upper shrouds.
  4. Gooseneck assembly is what attaches the main boom to the mast. The gooseneck should be strong and light. Aluminum is an excellent material to fabricate the main assembly. Ideally, the assembly includes fixed rotating points for the boom vang and boom.

The engine that drives your Victoria. or for that matter, any sailboat, is the sails. Because of the scale of the Victoria, the desired sail shape should encompass minimum camber (draft) so that an overpowering effect does not occur.

Some model boat sail makers cut their sails in paneled sections. Each panel's seam has a pre-determined camber (curve) cut into it. When two panels are joined, the draft (camber) is built into the sail. When too much draft is used, the sail becomes too full, and the result is overpowering. Due to its low ballast to sail plan ratio, the Victoria is not forgiving, and it is the author's opinion that when the wind velocity is 5-7 mph and above the Victoria is overpowered with typical paneled sails.

In the author's opinion, non-paneled sails with a predetermined luff round (curve in the luff) are an acceptable alternative to paneled sails. In high winds, non-paneled sails enable the skipper to have better control over the desired sail shape. Thus, when the wind velocity is high, adjustments can be made to adapt to the particular wind conditions. Therefore, the author believes that for the Victoria, a flatter sail plan will offer improved performance as opposed to paneled sails. This observation is based on the Victoria's scale as mentioned above. Larger scale model boats usually have improved ratios to work with, i.e., a longer water line equals better stability and higher ballast to sail plan ratios.

The flowing suggestions are recommended for rigging your sails to the spars.

Insert a jib stay (30 lb fishing leader wire or 50 lb spectra line) through the luff pocket of the jib. Both the jibstay and jib sail tack are attached to the jib club, see Figure 5. The other end of the jib stay is attached to a line (spectra) with a bowsie installed for tuning adjustment. A separate line is tied to the jib head and should include an adjustable bowsie as well, see Figure 6. The jib clew is attached to the jib club where an adjustable outhaul bowsie is installed. Tie a small loop from the sail clew to the jib club, see Figure 7. Some skippers prefer to have a jib topping lift to control jib twist as a function of tuning for different wind/wave conditions, see Figures 6 and 7.

For the main, also follow the above procedures for the clew attachment. For the luff attachment, several different methods can be used. The author recommends using either small loops tied around the mast or what is commonly referred to as the jack line system, see Figure 8. For the main tack, tie a line to the tack eyelet and then route the line down from were the sail tack and boom gooseneck is located. Insert a bowsie for down haul sail tension adjustment, see Figure 9. At the main head, tie a line at the sail eyelet and secure it at the mast head fitting, see Figure 10.

To attach the jib & main sheets that are routed through the fair leads on the deck (see Figure 3), use small fishing fast lock snaps, attached to the ends of the sheets, see Figure 11. Use a square knot when attaching these snaps, but before you do, secure them so you can determine the initial set point for sheet travel length. For the spar side attachment (jib club & main boom) use split rings or small washers, attached to a 6" or so length of spectra with an adjustment bowsie. The snap lock fitting and split rings can be purchased at most any fishing supply stores.

Set your sail winch so it is in the close hauled position, and attach the sheets to the adjustable bowsie line on each boom. With the rig in the close hauled position, adjust the split ring bowsie line so that the end of the jib club is pointing to either port or starboard shroud. This jib club set point is usually an excellent way to develop the slot effect when going up wind on a close hauled tack. Depending on the type of sails you have, further adjustments to the split ring bowsie line may be required.

Editor's Note: This article is a part of an on-going series on performance modifications for the Thunder Tiger Victoria, for further information contact Maritime Product, Inc. they are listed on the Vendors Page

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