I built a 36"Aerokits Fireboat in the UK in 1970, left it behind on emigrating, and built the larger version in Australia in 1974. That one had a 10cc Veco 61 engine in it which would be just about Impossible to operate anywhere now so the glow plug engine was removed and a Turnigy brushless motor and LiPo batteries successfully installed recently to make a fast, quiet and reliable boat.
I bought the Perkasa kit recently on eBay to make a change from many long years making model steam locomotives and traction engines. This is an older but complete kit, with the ply cut with dies rather than laser cut which I assume Precedent use currently. Because the die cut method was then (I don't know the age of this kit but maybe over 20 years?) limited to 3mm ply, several bulkheads and the keel have to be laminated to produce the 6mm thickness required. This introduces an Immediate problem because the resulting 'laminate' is not particularly straight, and the keel extremely flexible. The design of this boat is quite different to a fireboat on that it lacks the two cabin sides which make the fireboat such a rigid and easy structure to build - the fireboat having in the main, thicker bulkheads also.
To keep the keel straight during construction I have clamped a heavier section of straight timber to the keel with the bulkheads resting on a flat building board. The lead weight is off my dive belt and was used to hold the front down initially.
More later.....

These pictures show the structure with the longitudinal stringers on. For such a large structure it looks more like an aeroplane than a boat and as it stood then, is quite flimsy. Why bulkhead 9 (4th from the transom) is made so weak and fragile I don't understand as the top of it could have been left in place and cut out by the builder at a later more rigid stage. if this structure is compared with say, the Dumas Boats PT109 model, you will see what I mean about flimsy - the Dumas boat looks positively 10x as strong!
The three turbine exhausts on the real boat are a distinctive feature but the Precedent kit only supplies precut ply discs to represent exhaust covers, which of course are laid down onto the rear 'shelf' when the boat operates. My boat will be well and truly operational so I wanted to see up the turbine exhausts, not block them up with covers. Three jet pipes were made from plastic pipe fittings and the transom cut to accept them - the pipes are of course blanked at the inner end...... Three 'angle Iron' rings were also turned in PVC pipe fittings to suit.
The last picture shows the first ply skin being glued on. My 46" Fireboat was glued together with Aerolite 306, remember that? (younger readers can yawn here...) but it has recently shown signs of coming apart in places - it was built in 1974 after all - so this hull is being assembled with 30 minute epoxy and I hope it lasts as long.

Last post I compared the KD Perkasa construction to the Dumas Boats kit of the PT109, and I thought that if only a few people would have seen this for themselves some pictures were necessary.

This is an old kit bought on eBay that my son is currently building. Dumas are an American company still in existence and this kit is currently available. The boat is about 2/3 the size of Perkasa (33" long compared to 49.5") yet have a look at the construction which is completely different and in my opinion will build a stronger and stiffer boat.

The Perkasa has a fairly complicated front end - nothing like as simple as the Fireboat - and transitions from the planar shapes of the main plywood skins to a sharply curved, complicated shape which will eventually be carved from balsa blocks. The transition starts with narrow strips of ply which the instructions say to butt joint and glue together. I have added 1mm ply strips behind each of these butt joints to add reinforcing but also to make sure they join together without 'steps' in height. Thoughout this construction I've also added 1/4" square reinforcing wherever I can.

The photo's show my slow progress. The balsa blocks have been added, carved and sanded to shape and then the whole front underside coated with body filler and sanded smooth.
The balsa is in a very vulnerable position and very likely to suffer dings in use, so I am coating the whole front end with two layers of 3/4 oz fibreglass cloth and epoxy resin. This process is new to me, although I've repaired fiberglass canoes in the past but not then worried too much about the finish. This time I used finishing epoxy which was made more 'spreadable' by adding metholated spirit to the emixture. it evaporates before the epoxy hardens but makes it more 'runny' and easy to spread.
It was a relief that it hardened well and sanded easily to remove any drips. The excess fibreglass cloth also sanded off easily.

The hull ended up with a single layer of fibreglass cloth and epoxy over the whole thing, and three layers over the balsa at the front. I don't want the balsa end grain showing through in the future. The superstructure received two layers over the balsa bits also. I have never fibre glassed a model before but I found ¾ oz fibreglass cloth is very forgiving and will readily accept being fitted to quite complex surfaces. if it is too complex a shape and you end up with it folded up or overlapping itself, don't worry because when it's all hard it sands flat very easily.
I used Z-Poxy finishing resin (www.zapadhesives.com) instead of fibreglass resin and found it very nice to use, even if thinned with meths it certainly went hard enough to sand after leaving overnight. On the flatter surfaces of the hull I spread the epoxy with discarded playing cards to leave little excess on the cloth. if you sand too hard you can easily go through the cloth so it's best to lightly sand and fill any open weave with filler.
The superstructure parts really didn't fit that well but after adding some packing and opening out some slots it all went together. I really don't want to see any evidence of balsa or balsa to ply joins in the future, hence the attention to covering it with fibreglass, which left a nice hard surface.
Motor was aligned and installed as shown, and the boat now has a home-made rudder and water scoop installed. I bought an 18 inch prop shaft but cut 1.25 inches off it before it was epoxied in place to get the motor near the centre of the hull.

Most of the painting completed and down to fitting out. The transom flap has been added - not hydraulically operated as in the real thing, but angle adjustable anyway. The transom shelf was originally made removeable - a ply back behind the balsa curvature allowing it to bolted on through the two stay anchor points. it was however bolted and glued in place because it would probably be used as a handle to pick the boat up out of the water... The exhaust flaps are fixed in the open position so at least the turbine exhausts will be open in operation.
Some fiddly bits are now taking my time, like fixing a servo under the Bofors for rotation, and another, modified to continuously rotate, attached beneath the radar scanner. I purchased an electronic servo slowing device which was a disappointment since its operation was slow but jerky in one direction, then rapid on the return! Most unrealistic unless you were to apply it to a plane's undercarriage retract - which is what it was meant for. The continuously rotating radar can be slowed to a stop or speed adjusted simply by using the trim on its R C channel.
Paint was simply aerosol cans from a hardware store, which unfortunately were only available in gloss. However, the same paint supplier sold satin finish clear acrylic spray in aerosols too and his has done a good job.

Perkasa now finished and maiden voyage completed, build time a bit over five months. Radar rotates and lights work, and Bofors rotates under radio control. initial trials showed that the prop shaft inner had been made out of some bent stainless and it whirled alarmingly at speed, making a horrendous noise. The shaft is quite long and with bearings around 18 inches apart it is very flexible, and the bend when it was stationary just got worse as revs increased. Straightening was found to be Impossible but some Improvement was obtained with a mid-position, pressed in, Teflon bearing, and the terrible rattling/vibration noise was reduced by replacing the rear brass bearing with Teflon. A new inner shaft has however been ordered.
With the same motor and batteries as my 46 inch Fireboat and no extra ballast, the Perkasa weighs about 600g more, but its performance seemed to be slightly faster. This boat does have a 5mm larger propeller but still it only drew around 55A maximum. At high speed it lifted noticeably at the front so after the first run I have added some 300g of leaded vinyl - taken from an old X-ray gown - placed under the Bofors. The hull shape at the front is much more successful than the fireboat in keeping water off the deck at slower speeds, but the hull becomes dead flat at the rear making this a real planing boat capable of high speed. With a single motor and a fairly big prop I found considerable torque reaction, and on the first run I couldn't trim the boat to run straight, it just wanted to turn right. The rudder was adjusted quite a bit to overcome this, but I suppose that's not much of a price to pay if the alternative was contra-rotating motors and props, or three props like the original!
😎

Nothing completes a model like adding some crew to drive It, so at last I have added five scale figures from the Battle Crafts range and painted them a tasteful navy blue.