Some years ago I visited the Liverpool Maritime Museum and noticed a model of HM Coastguard cutter 'Vigilant'. This was an attractive static model, but one that seemed to have the potential to be made operable.
After some research, determined the vessel was a derivative of the Dutch Damen Stan 4207 patrol boat. There are many pictures of this type of vessel in the liveries of several countries on the net. However, after numerous inquiries searching for plans or drawings, was advised they would not be available as long as this was a current production vessel.
Thus decided to shelve the project and continue with building other models concluding with HMS Beagle, my previous blog. This was in the hope that eventually a lead on drawings would arise.
Last winter our Club was invited to tour a Canadian Coastguard 'Hero' class vessel which is berthed locally. The tour reawakened my interest in a patrol boat model, particularly as the 'Hero' class is another Damen Stan 4207 derivative.
My search for plans was initially unsuccessful, but a Dutch contact made inquiries directly with Damen and they kindly set him a set of sheer lines, sections and GA drawings. These contained enough information to develop a set of model plans.

After examining the Damen drawings, decided build to a scale of 1:42, giving an overall length of just above 40'.
Discussing the project with local enthusiasts established that a model of the Hero class had been built recently, but by working from photographs and that a similar style patrol boat had also been constructed. Experience from these projects showed that both weight and stability were critical.
The actual vessel does not draw much water and has considerable top hamper. These features have an effect on stability. Did not want to increase the hull depth, although this is a well proven technique to help address these issues. Concluded it would be necessary to build lightly and to keep the weight low.
To help control stability, plan to make the complex mast structure as light as possible using aluminum and styrene sections and then make the hull stabilizers operable, as in the real vessel. These should help offset any tendency for extreme heeling in manoevers.
Have considered slinging the ballast/batteries under the hull to increase righting moment and will make provision for this during construction. This feature will not be activated unless trials show it necessary as it adds a non-standard feature, even if it is below the water-line.
Efforts to minimize weight will also determine the battery type, construction techniques and materials.

From the Damen sheer, lines and section drawings developed building plans.
Decided to use a traditional 'plank & frame' construction style for the hull, which should suite both the hard chine design and help minimize weight.
Most readers are familiar with this type of construction, so in future will only describe features introduced to recognize specific hull design details or those added to achieve lightness with a low centre of gravity.
The basic framework was straightforward; decided to build the hull frame and then fit the sheathing (between keel and chine) first. This would create a definite hull form where all the electrical equipment could be trial positioned and installed, but still allow reasonable access. The upper planking (from chine to deck) will be fitted once this is complete.
The Daman section and sheer plans show only a limited number of sections, in the interest of lightness, decided to build the hull framework using only bulkheads corresponding to each section. if the hull proved flimsy these could easily be increased.
Due to the shape of the keel laminated the rear portion using 1/8' ply and wood strips. As the hull has a definite sharper keel section towards the bow, eliminated the wood strips to achieve this.
Used ¼' sq. bass wood strip for the deck level and chine strips and a rudimentary stiffness check of the frame showed a satisfactory result. The limited number of sections is probably assisted by the hull shape which is has a considerable length to beam ratio, with sections transitioning smoothly. Tried to use ¼' balsa strips for the deck strips but found they were too brittle, even when soaked in ammonia. Decided the potential weigh saving was not worth the trouble and reverted to basswood.
All the hull section and keel assembly was fabricated on a building board with cutouts corresponding to the section positions to locate the bulkheads and ensure squareness.

The lower portion of the hull frame was covered with one piece of 1 mm marine ply. This requires considerable manipulation to fit around the propeller tunnels. This was done by gluing the skin initially to the keel and then slowly working out to the chine. Between each manipulation of the ply skin it was clamped and glued in place with a two part epoxy. The process is time consuming, but the adhesive strength makes it worthwhile. The ply sheet can be made to follow the section contours by heating the ply with a heat gun which melts the ply internal adhesive and allows the sheet to take up the desired shape. One of the more unusual features of this vessel is that the chine strip is visible between the upper and lower hull sheathing. Not only is there a definite horizontal surface, the upper surface protrudes beyond the edge of the hull sheathing to form an integral spray rail, see pictures. A length of 1/16 x 3/8 basswood strip was inserted into slots cut into the bulkhead sections. This was then glued to the top of the chine strip to reproduce the shape. Once the upper sheathing is fitted this will be trimmed to the final dimensions.
Usually with a frame and plank hull I reinforce the joints with glass fibre tape and fibre resin. Decided to try a different approach; had a tube of construction adhesive at hand which would stick well to a blanket. Ran a fillet of this alongside the keel and then around the areas where the chine strips meet the sheathing. This turned out well, both reinforcing and sealing the joints. it is also much quicker than the glass fibre approach, probably lighter and less messy too.
At this stage added a section of steel coat hanger bent to follow the contours of the bow. This is to protect the bow in an inevitable contact with the pool side. Located it with epoxy resin and faired into the sheathing.
As the areas behind the bow and in front of the transom will eventually become inaccessible, ran liquid glass fibre resin into them to seal and strengthen the joints.
To assess attempts to control weight; measured the weight of every major component that will be installed in the finished model. On refection, the conclusion was fairly obvious. The batteries, motors and bow thruster are significantly the heaviest items. Relays, servos, ESCs and Rx will have very little effect on the overall weight of the model. NiMh batteries are around half the weight of similar capacity sealed lead acid cells and will be used. This type of battery is slightly heavier than more expensive NiCad etc.

After filling irregularities around the lower hull sheathing and smoothing them out, tried a trail installation of the major electrical components. These all seemed to fit in quite well, so decided to cover the lower portion of the hull with glassfibre cloth and resin.
Once this was dry and initially rubbed down, installed the propeller shafts. Another modeler once recommended fitting the outer shaft tube into a sleeve that goes through the hull skin. Decided to try the approach and would recommend it to others. it splits the alignment of the shafts into two operations; plan and horizontal alignment and then shaft protrusion. it does make it much easier. installing the shafts still requires meticulous measurement and checks so the shafts are parallel in all planes.
Had earlier fitted the motor mounts as they are necessary to ensure correct shaft alignment. The mounts are made of aluminium sheet cut and bent to shape. This was bonded to the inside of the hull.
Mentioned in Blog 2 that an option to hang the batteries or ballast beneath the hull to increase righting moment would be installed. All my models are mounted for display on trunnions fitted into the keel. Decided these points would be ideal for screwing in threaded rods onto which the batteries or ballast could be hung. Shaped wooden blocks were fitted to the base of the hull. These straddle the keel and are at the forward and rear mounting points. Drilled through the blocks (and keel) and installed captive nuts. Beneath the nut fitted an automotive style wire connector into which a fly length of wire had been soldered. See picture of assembled and fitted front mount. These wires will be linked to main power distribution point when that is located. if not required the wires can be clipped off.

Fitted the bow thruster casing, this also requires very careful measurement and location before gluing in place. A brace was added to firmly locate the thruster as the adhesive dried.
Reinserted the propeller shafts and trial fitted them. The motor couplings were installed along with external sleeves to hold them rigid. This enabled the motor and mount assemblies to be aligned. Found that leaving the upper hull sheathing off helped eased this operation as can measure and use straight edges in both planes.
The next items to install were the stabilizer fins. Made the fins out of styrene sheet bent around a brass rod, the gap was filled with epoxy adhesive. This holds the rod in place and gives the styrene the requisite aerofoil shape. The rod slides into a brass sleeve to allow the fin movement. Fitted the sleeve into a wooden reinforcing strip glued to the hull inside face. Took care to ensure the brass sleeve inner ends terminated above the water line. Described this rudder building technique in my HMS Beagle blog and can report it works equally well for stabilizer fins as for rudders.
Fitted rudder horns onto the brass shafts inside the hull and made up a linkage using old bicycle spokes. Thought this might be difficult as the two stabilizer shafts follow the contour of the hull bottom and are inclined towards each other with an included angle of around 140 degrees. By bending the linkage to replicate the contour found the movement remains free.
One of the rudder horns was then connected to a servo to operate the fins. As the servo is mounted parallel to the keel top and the fins are inclined, during operation there is a force that tries to slide the rod out of the servo horn. This was overcome by using a threaded portion of rod through the horn fitted with a nut to hold the rod in position.
Not sure if the fin movement should follow that of the rudders (the sense is opposite, but do they move through the same arc at a similar rate?). To allow corrections the stabilizer linkages were made adjustable. The first test sails will show if any are needed.

The twin rudders were made out of styrene strip and brass rod, which slide into brass sleeves in the hull.
The rudder horn movement is severely restricted by the rear hull RIB well. The rudder posts are adjacent to the inner wall of the well precluding fitting a rudder horn that allows free rotation. To overcome this fitted the rudder horns facing out board from the rudder posts. The adjacent bulkhead had been recessed to allow the horn to swing freely into it.
The rudder linkage rods were fed forward to a set of cranks and then linked together. The cranks were then joined to a servo with a short link. The intermediate cranks were introduced to allow free rudder horn movement. The RIB well can now be completed as the rudder mechanism works.
I use the same Tx with various linked Rxs fitted to several models. To avoid confusion over control sense it is important to ensure all Tx movements remain the same. Thoughts currently are to control both the stabilizers and rudder servos with the same Tx lever. This means the linkage must allow one of the servos to be reversed, which in this case should be the rudder to retain consistency with other models.
Unsure of the degree of stabilizer fin movement relative to the rudder so procured paired, and also mixing servo wiring harnesses to experiment. Each linkage has adjustment capability, so the results of sailing trails can be incorporated.
As had now resolved the rudder movement issue decided the sterngate, which is behind the RIB well, could also be made operable. Perhaps one day will also make the RIB operate!

Gave the sterngate some thought and decided a strategically located bell crank and linkage would transmit sufficient servo travel to open and close it. This would also allow limited access to the servo and linkage to assist in any eventual repairs or servicing. A mock up of the installation confirmed this. Transferred the dimensions and layout into the hull and installed the sterngate frame. This moves correctly as the servo is stroked.
Could have now moved to sheath the outside of the hull and fit the deck. Decided it would be better to install all the electrical components first and then do a trial run of every function in case any issues arose. This proved wise, many minor adjustments had to be made to bulkheads and structure to allow control rod and wiring.
Once everything was installed, connected the components as appropriate and powered the various systems up.
The rudder, fin and motors all worked as planned. The fire hydrant pump and the bow thruster were also fitted. The direction (polarity) of these components is important so the wiring was colour coded to ensure correct final fitting.
Once all was installed and operating correctly, weighed the partially completed hull recognizing that with the major components fitted the weight would not be too far off the finished weight. it weighed in at about 6 lbs, so estimate when the hull is fully sheathed and painted it will be around 7 lbs. This does not include the superstructure and lighting.
This was an opportune time to photograph the interior installation and some pictures are attached. The wiring was deliberately left loose so it could all be removed and reinstalled when the hull sheathing was complete.

Removed all the internal components and wiring, then painted the inside of the hull with a light grey paint.
The upper hull was sheathed with 1mm ply from the spray rail to the deck. The construction adhesive used to reinforce the bottom sheathing worked so well, used it entirely on the upper. Applied a generous amount to the faying surfaces, then squeezed the excess out and smoothed it into a fillet shape. The forward hull sheathing was left oversize as the drawings show the hull side contours extend up beyond the deck to become plated bulwarks.
Once the upper hull sheathing was complete, fitted a series of brass rod stanchions to the foredeck to support both the upper hull sheathing and a section of styrene used to extend this sheathing up to the top of the plated bulwark, as shown in pictures. Have found the stanchions idea helps when butting one thin sheet to another as it reinforces the joint.
After the adhesive had cured, the plated bulwark upper edge was gently filed to the correct contour and size. The hull sheathing was covered in glass fibre cloth and resin, which was lipped over the bulwarks and then carried down the inside face to deck level. This adds immeasurably to the stiffness and robustness of the bulwarks.
Have always thought hard chine hulls would be easier to make than round bilge ones. This one has proved the opposite, perhaps the raised bulwarks, operable sterngate, RIB well and chine rails have added to the complexity and account for the challenges experienced.
The hull has now been covered in glass fibre cloth and resin with the interior painted. This was an opportune time to fit everything and check operation before the rubbing down and finishing was started. Any further modifications could thus be completed without damaging the finished model. All the components were refitted and the operation rechecked.

The weather is still mild in Canada and our local boating pond has not yet become an ice rink. Decided it would be worthwhile to check the ballast (to be sure the hull was not too heavy, thus rendering it scrap), then assess performance and the operation of the fin/ rudder linkages.
The day dawned windless and bright, ideal for a test sail. Lowered the hull carefully into the water and checked the waterline against the marks added from the plan. To my immense relief, both bow and stern rode above the waterline marks. The stern rode higher than the bow. This was reassuring as the bow already contains most of the final features, but the stern requires engine air intakes, the RIBs , cranes and other finishing details. As these are added the stern should sink lower, raising the bow.
Although the 2 x 7.2 X 5000 mAh NiMH batteries fit snugly on both sides of the keel they can also be moved towards the stern to help obtain correct levels. This means the final balance can probably be achieved by moving components and not adding ballast.
The moment of truth! Powered the model up and was pleased by the operation of the fin/rudder combination. in hard turns, if anything the hull inclined into the turn; nevertheless it was stable. This suggests that operating the fins and rudders at the same ratios is close to correct. Using a servo for each mechanism simplifies the linkages and internal congestion of the model.
The speed of the model far exceeded any semblance of scale, making the controls sensitive and unstable. Currently have the batteries connected in series, will modify to parallel and hope this should give a close to correct performance.
This experience was similar to my HMS Beagle model, which is considerably heavier and bulkier. As the power trains are virtually identical, the reduced voltage should be near correct.