Baldwin Racing
This Pit talk article is going to show you how I go about building a V-hull boat. I have picked the Tornado only because that is the boat I have just built and was able to take pictures step by step as I completed it. You can however still use this article to build any boat of your choice.
I hope this helps those new comers that would like to start building their own boat. It will illustrate almost every step in detail. Once you have read through this article you should have no problem building your own boat. This boat is very advanced and has all the little things that can make it the world champion boat. Some items that are installed need not be done in the beginning but I advise you that if you are to get serious about this sport you might as well start right.
Take note that I make everything that goes into the boat besides the Motor and Radio. In this article I bought the Hull and Deck from Prestwich Models as I must give credit to Dave Marles for designing fantastic boats. Unfortunately not everyone is able to do this as you require a fair amount of tools to manufacture the components. The tools that I used in this process are as follows:
If you would like to ask me any specific questions just E-Mail me. I am also open to suggestions as I do not prophesy that I know all. Good luck in your building and happy reading!
Before I start building anything into the hull and deck, I first make all the main components that normally have to be epoxied into the boat. I do this before, so that I can install the components in batches to save on epoxy and to enable me to plan better in the process of putting the boat together. All the other little goodies that go into the boat are normally made as and when required in the process.
This shaft housing is made from stainless steel tubing 9mm in diameter. My shaft is made from stainless steel 6.4mm diameter rod and is machined to fit bearings on each side. This shaft thrusts at the engine side. I weld plates on the tubing to fit it to the hull with two stainless steel bolts. I then weld a lubrication pipe onto the tubing to enable me to lubricate the bearings easily once it is built.
The rudder shaft is made from 9mm stainless steel tubing that is welded to a 1.5mm stainless steel base. The steel tube is machined to ensure that it stays at 90 degrees and then gets bushes put in the tube to allow for a good fit on the rudder shaft. The length of the tube is subject to your radio box height but I make mine 40mm long. Normal silicon tubing is used to seal the rudder at the top of the shaft. The servo lever arm pushes against the silicon and is thus used to keep the rudder in place. The rudder shaft is made either 5mm or 6mm in diameter.
The trim is a little more involved to manufacture. There are 5 main components namely the trim plate, cam, cam housing, rubber mount and rubber housing. The rubber mount is an off the shelf item that you buy. The size I use is a 4mm thread with a 15mm diameter rubber. The trim plate is a 6mm thick aluminium plate that is put in a milling machine and machined to a wedge shape. That is 6mm on the one side and 1mm on the other side. The size of the plate is to your discretion but I recommend that you make it approximately 40mm wide and 50mm long. The cam housing is made from aluminium and turned in the lathe. The entire height of this housing is 32mm high. A 12 mm hole is made in the middle but stops just 2mm from the bottom of the housing. At the bottom a 5mm hole is made to allow the cam shaft to protrude to enable it to push onto the trim plate. The cam itself is made from 12mm stainless steel rod. I Mill an angled slot into it as indicated in the picture. The slot is made 3mm wide and then I machine a 4mm screw down to 3mm to hold it in position as well as to allow it to slide in the slot. I then drill a 5mm hole in the middle to allow a 5mm shaft to go through it. The shaft is what pushes onto the trim tab to lift it. A rubber seal is put onto the shaft to seal it from the water. The rubber housing is basically just a cup that goes around the rubber.
I use a header tank that was designed by my father in 1983 when I just started racing. I used it in the first international event in Braunschweig Friendship Regatta and came first in B class with 64 laps running a 6,5 cc motor at the time. At that time I also only had a 2 channel radio. This tank really works and enables me not to worry about my mixture as it stays the same throughout the race. The design is similar to a normal toilet cistern that keeps a certain amount of fuel in the bowl at all times. This design then allows a constant pressure as a result of gravity feed to the carburetor. You cannot get better than that. It also makes the carburetor less sensitive due to lower pressure.
This picture shows you the bulkheads that I make by putting a layer of glass cloth on each side of a sheet of spheretex. This gives good strength with very little weight. I use the same thing for my radio trays.
These are all the components that get fitted to the deck before it is joined to the hull. I use 4mm bolts and nuts for all the places that need screws.
This picture shows you most of the parts that are used to complete the boat and be able to run it. The tank is not here but is shown later when it is made. It is now time to start putting this stuff together.
Before you start with any cutting you should identify your dimensions based on the plans that you are using. The standard dimensions issued for the Tornado hull when purchased are indicated above. If you are not building a Tornado you should get those dimensions before you carry on any further in your building.
The hull is cut to allow for the drive shaft to go through. It is also cut to allow for the trim tab. The hole for the rudder shaft is also marked and drilled. The dimensions are normally supplied with the hull when ordered. These dimensions are different for every boat. I sand the areas where I will be putting epoxy with some rough sand paper before I position any of the components in the hull. I spend some time on the shaft as I feel that this is the most important part to get right. The shaft is put in the hull with an extended shaft approximately 1 meter in length. This allows you to clearly see if it is straight or not. I do not put any angle on it. I put it in straight. Not a little to any side. If you really want to angle your shaft to one side then you must angle it to turn the boat left. Never put it in the other way. I do not bother to measure the angle of the shaft from the boat as I only measure the point at which the prop touches the hull and the engine side of the shaft is installed as low as possible. What ever that angle is, is the angle.
The shaft is aligned straight with the rails of the boat. I put NO angle on the shaft. Some boaters put up to a 3 degree angle but I have found that that causes more problems than good. The shaft is put in as low as it can go. I normally put the biggest prop I think I will use and then place the shaft so that there is approximately 1 mm gap between the prop and the bottom of the hull. I install all the parts that I intend to epoxy at one time. This is shown in the picture. Contrary to many boat builders I do not install the motor mountings at this time as the shaft alignment is important for me to get in and set first. Once the shaft is dry I will install the engine mountings. I do this to ensure that I do not move my shaft once I have aligned it. If the motor is installed with the shaft it gets in the way when you want to align it.
I use aluminium tape to hold the trim in place while I epoxy all the parts in. I also use it to seal the bottom of the shaft, so that when I epoxy the shaft in, it moulds the correct shape at the bottom of the boat at the same time and I get no dripping of epoxy from the shaft.
As you can see the parts have been epoxied in and the engine is now ready to be fitted.
Again contrary to all boat builders I do not install 4 rubber mounts. This again is a Baldwin trade mark where I only use 2 engine mountings as indicated in the picture. I use a rubber coupling which is the same as the engine mounts to hold the engine in line with the shaft. This design allows free movement of the motor to self align the motor and to reduce energy dissipation into the mounts. The engine alignment to the shaft also becomes less critical and you are able to fit the engine very easily. I have deliberately installed a motor 10mm skew to the shaft with this design and run the boat in a race to test it and found no problem. I now know that if its 1mm or so out it will give me no problem at all. I have been using this design for more than 12 years without a problem. Believe me, it works.
When I fix the engine mounts I also install the water pickup. I only use 1 pickup, again contrary to other belief's. But it works as you have more than enough cooling. Some fastening hooks on the left hand side of the boat are installed as indicated in the picture. These hooks are used to tie down weights on the inside of the boat. It allows you to then vary the weight and not let it be seen from the outside. The hull is now ready to get the deck fitted.
The deck is marked with a marker where I want to cut out the Engine,Tank and Radio hatches.
I then enforce those areas with Carbon Fiber cloth, one layer to make it a little stronger. Before I cut anything I grind a slot in the area where I want to install the hinge for the engine lid. The hinge is then installed. Once that is dry, I use a miniature cutting disk to start the cut. I then complete the cut with a hacksaw blade. I then install all the clamps and bolts to hold down the lids.
The picture shows the bolts that are installed on the deck before it is joined to the hull. I make a little compartment in the nose to hold the header tank. This is done on the deck to ensure a good seal is made as once the deck is joined it is more difficult to work there.
Well that's all for now folks. PART 2 will carry on from this point (Step 4 - Joining the boat). I hope this information has been informative and given you ideas.
Compiled in September 1997 by Gary Baldwin
Last Updated on 29 December 1998
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