Setting up the GTM 'SNARK' Pickle Fork Hydroplane

Setting up the GTM 'SNARK' Pickle Fork Hydroplane

by Ernie Lazenby

The following is information as to how I got this boat to work. I do not accept any responsibility in the event of boat failing to work as expected. I can only say that what I describe works. It is likely other people have other methods and may even be able to improve on what I have done. That being so then spread the word. Refer to the photographs where necessary

For maximum speed I opted for a surface drive system. Experience dictates that this is the best drive system.

   

Power Graupner Speed 400 motor 6 volt version

Cells 7 x Sanyo 800 AR

Prop Octura X431 plastic

Hardware Octura .098 cable into a 1/8th stub shaft running a vertical bracket fitted with 2 x 1/8th lead teflon bearings.

Rudder stainless steel, shaft is 2mm stainless running in 2 x 2mm bushes.

All brackets are made from aluminium as is the motor to shaft coupling

The centre of the prop hub is set very slightly above the line of the sponsons and on my boat the prop is angled very slightly downwards.

The sponsons have been fitted with ride plates made from lite ply to provide sharp edges for the water to break clean.

Position of the internals

The motor is mounted slightly off centre to the right when viewed from the transom. The front of the motor is 120mm from the transom.

The RX is on the right hand side approx. 30mm forward of the transom. The micro servo is on the left side towards the rear corner. The speed controller goes well up front in the centre of the boat. The cells are split into - 4 for the left side of the motor and three for the right. The cells need to go quite well forward to produce a COG approx. between 150-160mm forwards of the transom. The driver has been filled with foam and glued to the superstructure. A turn fin is required for the right hand sponson. This fin does not need to be big nor should it be otherwise it will cause drag. This boat drives very well and is suitable for a beginner or experienced racer. It turns well and is suitable for racing similar size boats. The above set up will give a run time of slightly more than 5 minutes 30 secs.

At the time of writing the boat was to be tested a Graupner 480BB race motor, this has now been done with speeds that approach 30 mph