12ft Tunnel Build

**ice_spy** · 03-23-2014

Hello BRF members,
thought i would post up the build of my new race boat.
I purchased the sport c tunnel hull plans from Bob @ DillionRacing.com , also the cockpit plans for a fully enclosed cowling.
Constructing with 2 sheets of 3mm & 7 sheets of 6mm okoume AAA marine ply with radiator pine for all other lumber. 'West system' epoxy resin for the glue.
Trying to build as lite and strong as possible, racing the 25hp class here in Aus, with a goal to race in the 112klm Bridge to Bridge. record stands at 75mins.

Stock Mercury / Tohatsu Seapro 25hp restriction plate removed with advanced timing same as 30hp.
Mercury Racing chopper II 18p and Powertech through hub 14p.
Running a jack plate, hot foot, cable drum steer and a small nose job for higher running.

Approx 18hrs into the build, working with imperial measure has been slowing me down but im getting there with only weekends to work on it.
I have changed the shape of the sponson outer decks and gunnel strip also flattened the bow ramp angle on the tunnel floor. The motor board will be set back further aft, allowing me to extend the rear cowling and move the cockpit further towards the bow.

Might see if i can sneak a night or two in the garage this week

**Chairman** · 03-24-2014

Nice looking start on your project. If it's alright with you, I will "steal" pics off this thread as you post them and create a page for your build in http://www.dillon-racing.com/customerboats/ on dillon-racing.com. I'll let you know when the page is online. Bob

**ice_spy** · 03-24-2014

Plumbed up a level chipboard base to true the hull on. This will also make a good movable work bench when I put a top, some legs and caster wheels on it.
So far no permanent screws, staples or nails have been needed. Just epoxy and quick clamps.
Used a lazer pointer to check truness and straight edges.
Just need to check diagonals to see if it's all square before I go any further.

**ice_spy** · 03-24-2014

Bob, that would be great thank you. Please do.
I just hope I don't get the bug and want to build more ! I'm already dreaming again. Hahaha.

Really enjoying the build so far.
Week nights after work i think will become a regular activity

**Chairman** · 03-24-2014

"Boatbuilding Disease" is generally not fatal. "I-Wish-I-Was-Building-a-Boat Syndrome" is far more dangerous -- it will eat you alive.

**ice_spy** · 03-26-2014

Although I have read the construction notes several times, I still managed to detour from the suggested stages. For instance I still have to mark & cut out the transom bulkheads and sponson bow ends.
I want to build all areas at once, forgetting to closely following Bob's extensive notes have cost me time and mistakes. For instance cutting away too much from bulk heads 4 & 5 which I will now have to strengthen again. Also the third stringers that end between stations 4 & 5 i deleted, will need to be added back into the bulkheads.
I have decided to print out all notes and place into a folder so I can be more consistent with following important steps throughout the build.

Today I marked and cut out most of the halving joints for the tunnel stringers, although not in the plans, I have flattened the tunnel floor and added extra halving joints to give a little more strength. I'm going to need a long straight edge to keep the tunnel sides perfectly flat before I can fix the tunnel floor down.

**ice_spy** · 03-29-2014

Finished all the tunnel batons with halving joints across all the beams. I therefore had to router out some drain holes for the water to flow aft. I actually used 18mm (3/4") batons the entire lenght, so I will be using the router again to mill them down towards the bow to save some weight. Plywood floor is attached now also, however I ran out of light to take a photo.
I also placed my base/ work platform on some legs with caster wheels at each corner. So I can now stack my timber in the platform and move it around on the wheels.
Will get some more pics tomorrow

**ice_spy** · 03-30-2014

Put the rear section of the floor on this morning with a 3" wide scarf joint. Also placed 2" spray rails on the inside of the sponsons. Put a plywood bench top on my work bench/ tote trolly/ timber rack as resin was dropping all over my stacked timber. Added some more bracing to it also. Didn't seem like I got much done today but really I haven't stopped ! Can't wait to get stringers on and finish the bottom of the hull so I can flip it over

**ice_spy** · 03-30-2014

Spray rail and you can see how I've flattened the floor in this pic, although hard to see, I have curved the tunnel floor slightly towards the bow starting from bulkhead two