Grafting toy power plants onto a STCAN / FOM Model Boat


More details on this were published in magazine Ships in Scale Volume XVII Number 5, pp.72-74 (Sept-Oct 2006) under the title "Hull Grafting a STAN 'RAG' Patrol Boat".

What on earth is a STCAN / FOM Patrol Boat?

The STCAN / FOM patrol boat was used as front and rear guard of river convoys during the French Indochina war. The type modeled here was 11 m long, not to be confused with a smaller 8 m long version of same name. The acronym is for "Services Techniques des Constructions et Armes Navales - Forces D'Outre-Mer". It became integral part of the techniques developed for River Assault Groups (RAG), described in detail by Col. Victor Croizat, USMC, in "The Brown Water Navy: The river and coastal war in Indo-China and Vietnam 1948-1972" (ISBN 0-7137-1272-4). They were later replaced by US-made ASPBs (Assault Support Patrol Boats).

A few pictures of the real boat are available on the Web:
Dinassaut by Nowfel Leulliot and Danny O'Hara

Life in a River Assault Group (RAG 23)

Luc Luong Hai Quân Viet Nam Cong Ḥa

unrecorded source unrecorded source, interesting mottled camouflage, probably South Vietnamese Navy

The Malibu toy and the Monogram kit

There are several radio-controlled toy boats like the "Malibu" that measure about 5 inches long. These are made in China and are sold for less than $15 in department stores and gas stations. Their steering is provided by "on-off" control of two contra-rotating propellers driven by greased shafts, reductors, and pager electric motors. For hydrodynamic reasons, it would be practically impossible to control such a small boat with a scale rudder. Power is supplied by a 120mAh 2.4V NiCad. The Monogram kit of the "RAG Patrol Boat" measures about 10" long at a scale of 1:48. Its hull comes in one piece, and assembly is straightforward.

Hull Grafting Procedure

  1. Remove all the screws from the Malibu toy with a small Phillips screwdriver; some may be hidden behind stickers. This will allow to pry the deck from the hull. Once inside remove a last screw that holds motors and battery clamped to the bottom of the hull.

  2. With a pen, clearly mark which motor is on which side, then carefully remove the whole electrical system, battery, receiver, wiring, and the two motors. The recharging pin is difficult to pry out; best is to snip the charging wires close to it, one at a time, ifnot you will short the battery, a bad idea.

  3. With cutting pliers or even kitchen scissors with round tips, cut the Malibu hull so that you extract the propulsive group with as much flange as possible on the front and sides, and keep the propeller "tunnels" intact. Take your time, as there is no way back if you trim too much plastic.

  4. If you have damaged the recharging pins, or cut them off as suggested in step 2, replace them with a 1/8" or smaller "mono" jack with a small housing, as found in Radio Shack or equivalent.
  5. Now turn your attention to the Monogram hull. By successive approximations, you have to cut into it just enough for the propulsive group to fit inside, coming from the outside. The propellers should be aligned with the rear of the boat. It is best to avoid sharp or pointy tools, as plastic may yield without warning, and use a small saw or a slow-spinning "Dremel" to do the work.

  6. Once you have attained the best match for the propulsive group and the hull, join them together using any white silicone sealant that clearly says "sandable" and "paintable". It is best to do this in 2 or 3 successive steps, allowing drying in-between. Sanding and fairing can be done with plain sanding paper.

    Outside view of grafting Outside view of grafting, prior to sanding.

  7. Also apply some sealant inside to absorb the propeller vibrations. Then put back in place all the electrical system you had removed in step 2, and make sure each motor goes back ot its original side. Replace the screw and holder that were removed in step 1. Hold down receiver and wiring on the bottom of the hull with electrical tape. Secure the antenna to the front of the boat, as far away sas possible brom the motors.

    Inside view of grafting Inside view of grafting, with motors back into place. The battery will nest between the two shafts.

  8. After charging the battery and a test run in a sink, checking for any leaks, let the boat thoroughly dry and finish the kit, with intermediate painting of parts as necessary. For the final junction of the deck and hull, use transparent pure silicone sealant, and the boat will be totally waterproof, in case it gets rolled by a wave. The only hole in the hull is that of the recharging jack, easy to plug with an eraser head or small wooden peg.

    Top view The recharging jack is clearly visible on the stern.

  9. All is left to do is spray-painting, some detailing, adding the crew, and heading for the local pond!

The Results

Front view Ready to go with three Vietnamese crew and one American "Adviser"; not yet the Vietnam war.

Side view Fixed weapons were two .30 and one .50 machine guns; some also had a light mortar on the stern.

Starting Patrol Patrol under way. The STCAN had good armor but was a little slow at 9 knots.

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