Warren built his modified Laker SC12 in Mackay, North Queensland, Australia.

"This boat races in the 25Hp open hull class, which includes both tunnels and mono hulls. The only restriction is standard 25hp motor. Weight is very important, and when you weigh 90kg (198 lbs) it's a considerable disadvantage racing someone at 60kg (132 lbs)."

"We have 6 of these 25hp Class boats in our racing club. We regularly travel 7 hours to Bundaberg, South Queensland, where there are 12 boats in the class to compete with. This group is very competitive. There are 2 Plywood boats in this group, and I would say they are the Fastest."

Here, the lines of the altered plans are transposed over the original plans.

"The original Laker 12 is 3.73 meters long, but I wanted a boat 3 meters long. I reduced the width between tunnels to 1 meter. I also wanted a boat to have good acceleration, so I made the tunnels deeper to reduce any drag on the tunnel floor from spray."

"I did buy the 3 meter Mini Tunnel Plans as well, but I really liked the Laker shape, so I decide to alter the laker plans."

"Looks like it will fit a man and his dog (Aus. Slang). This is my grandson, the driver -- fearless."

"My first attempt at a scarf joint I used an electric planer to join the tunnel sides together. The hardwood marine ply dulled the plane very quickly. I later made a jig that I could use the power saw, much neater cut. I found the scarf joint to be the most challenging part of the whole project."

"After redesigning the bulkheads, I replicated them out of waste MDF (easy to cut into shape) and positioned them at each bulkhead station, then used string lines to check the profile along the hull. I decided to include a low-speed spray rail instead of the side and deck ending in a point."

"I made the bulkheads full length, one piece the full width of the boat. This made it easier to get the tunnel sides and bulkheads square, and I was able to check the profile before gluing."

"I lightened the bulkheads using cutouts. I checked the bulkheads into the tunnel sides and slid the frames together."

Tunnel battens in place.

"Cut the tunnel plank out making sure it was square then slipped it into position. I found this process secured all the bulkheads in position and square. Glued it together from here."

"I was concerned the nose was too sharp, but with a bit of force I was able to bend the battens to fit.

"I just followed the construction notes from here and completed the bottom."

Sponson battens installed.

Most of the boats framework, with all the bottom battens installed.

And just like that, the bottom is planked up.

"Turned over ready for coaming and Deck."

"Planning the seating, dash, and throttle pedal. A lot of discussion with the driver about the height of coaming. Again, stringline to determine the shape and width."

"Decided on a flat surface on the top side of coaming. My idea is that the flat surface may just help with aerodynamics."

"Trimming the deck plywood with a router to get it to match the coaming perfectly so there is no gap between the deck and coaming."

"No Join over tunnel sides."

"The seat is incorporated into the bulkhead mid-section. Unfortunately, it had to be relocated during fine tuning on the water."

"Also left a cut out in the coaming to allow access to pedals and steering drum."

"Motor Board. Just used epoxy and 2 dowels to attach to the coaming. Installed cleats later."

"Top Down. Good view of the access to the pedals and steering drum."

"Primed and sanded, ready for painting."

"The topcoat."

"Jackplate and steering."

"Finished the build. Now comes the hard part of trimming it on the water. With no hydraulics on the trim and height on the motor, its quite time consuming. Had to change the position of the seat and jack plate several times. Still experimenting."

"I estimate this boat at 200kg (440 lbs) fully rigged, without driver. Even though I tried to be conscious of the weight building it, I reckon it needs to be lighter for our class of racing. I have used lighter plywood than recommended in the plans and it has performed well so far.

"The boat mainly races on smooth water in dams and rivers, but it can get choppy when windy. The boat relishes the wind, helps very much with the aerodynamics. It bogs down in calm water with no lift. With no hydraulic trim it's no F1 at cornering, however if you take the corners wide you don't need to take your foot off the pedal which is an advantage coming out of the corner."

"Running a 25hp Tohatsu and Winrace prop, currently 55 mph."

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