Build thread: Cozy F1 T800 33" tunnel

[Dirk Jan Cozy]

I see a lot of nice hulls / setups here and I would like to share my latest F1 tunnel design and build.

I love to build wooden boats and this is my latest. It is my second F1 tunnel design; 7 years ago I built the Cozy F1 Tunnel 22.6".

I build and run my boats for fun, no racing. However I want my boats to perform, so I try to build them light and fast

I designed the hull In Inventor:



Cutting the ribs by hand, old school




Making the mid section with lowered bottom, just like the real F1 Tunnels:



Next to the Cozy F1 22.8" tunnel:

I hope you guys like it. I will post the next steps soon.

 

[Shane Bastick]

great build, nice looking tunnel and love the old fashioned way of building all by hand, as I mostly build this way too, lots of frames to cut out there,

look forward to more of your build thread

Shane

 

[brad nichols]

Is it all balsa constrution?

 

[Marty Slater]

dam cozy sure glade you came around!!

 

[Dirk Jan Cozy]

Is it all balsa constrution?

Hi Brad, the ribs are made from light plywood and the plating / bottom is from birch plywood. The longitudinal sponson ribs and the transom are made from birch plywood as well.
The entire hull will be laminated with glass cloth. Keep an eye on this build thread

Update: construction of the mid section continues



Lowered bottom:

Sponsons loosely attached for the overview:



Plating the sponsons. I use paper templates for making the shape. On the outer edges I keep the plating oversized and I sand it down.




The sponson ride pad angle (I think it is called deadrise?) Is 8 degrees. I wanted the hull to corner well. My 22.8" Cozy F1 uses an angle of 14 degrees. It runs very stable in a straight line, but cornering is not it's strongest point. I'm Trying to make some changes to see the result and increase my knowledge about these hulls!

The deck and tunnel section will smoothly transition into eachother; I like the clean look of it More to come next time!

 

[Dirk Jan Cozy]

Next build steps!

Plating the sponsons:


Applying glas cloth to every surface of the hull:




Adding the top of the mid section. Foam core is added as well here.

Making the servo plate from birch ply:

 

[Rob Pols]

Netjes gebouwd Dirk, complimenten, waar heb je de tekening vandaan ?

Groeten Rob.

 

[Dirk Jan Cozy]

Bedankt Rob. Ik heb de romp zelf ontworpen / getekend.

English: thanks Rob. I designed / drew the hull myself.

 

[Kris Flynn]

Stunning build so far Dirk!

 

[Carl Van Houten]

I built the Savage from full size prints just as he is doing back in the days of the pen plotters. Seeing your build brought back good memories. Great job! Thanks for sharing.

 

[Dirk Jan Cozy]

And we continue:

Reinforcing the transom with double plywood. Epoxied the nuts for easy mounting of the outboard.
Making a fillet around the extruded bottom with thickened epoxy:

Extending the back of the hull, just for looks



Laminating the hull bottom with glass cloth:

Determine steering linkages and servo position:

Attaching the sponsons to the hull by using a jig / template for correct alignment:

Carefully clamping the sponsons to the hull:


Next update will be plating the deck, more glassing and starting with the mold for the cockpit cowl.

 

[PaulSluce]

Yep another nice build Dirk

 

[Dirk Jan Cozy]

Thank you for the positive replies guys. Here's the next update.

The setup I'm going to use is as follows:
SSS 3674 1650kV motor
Turnigy Marine 120A esc
4500mAh 6S lipo
TFL large outboard leg V2
443 prop to start with



Complete drive weight is 590 grams / 20.8 ounces.

Filling the sponsons with foam and sanding it down:

I made a paper template for the deck plating. It will be applied in 1 piece:

Following the template, the deck fitted like a glove. It is made from 1mm birch ply:



Bottom of the hull. It is fully glassed and partly sanded, hence the spots that are shown.

Again using the deck template for cutting the 50 gr/m2 glass cloth:

And laminated onto the deck. Not in 1 piece this time, that was just too difficult

Next update: cowl mold and painting. I thought to include the cowl mold here, but I had too many photos to show still. Hope you don't mind

 

[Jerry Dunlap]

Just saw this amazing build. Sorta makes me feel like a slacker building out of foam.

JD

 

[Wasted wages]

Dirk, awesome build... very sharp and clean lines...

Two questions, What type of wood are the ribs, and how did you cut them out ?
Jig saw ? Xacto knife?

And what type of pour foam do you use in the hull?

Looking forward to seeing the final hull.
Really like the glass over wood construction method!
Any plans to release the prints or in kit form?
Thanks!

 

[XtremeRcBoats]

Very impressive and very fast built

 

[Dirk Jan Cozy]

@Wasted wages: the ribs are 3mm low density plywood, indicated I'm the diy store as 'for indoor use". Weight and strength is in between balsa and birch ply. I use this wood for many years for my home build hulls and I like it a lot. It is very cheap as well.
I cut it with a hand jig saw. As in the first post, I cut the ribs slightly oversized and I sand them down to the actual lines. It is a lot of work..

The foam is hard foam, cut from a plate. I did not use curing foam from a gas can. These foam boards are used for brick wall isolation and can be found in diy stores.

I noticed that the glass over wood is not very common here. Or at least, it looks to me that many Tunnels here are just sealed with epoxy, without the glass.
I wonder how do you prevent the wood from cracking over time?
I made a rigger and a hydro without glass and they both started to crack. Glassed both of them lateron

I will share the plans for free. I just have to touch up the design on some details.
Releasing a kit would be very nice, but I don't have the tools or contacts to make that happen.

@XtremeRcBoats: thanks I started the design 15 months ago and the build 12 months ago The hull ran already, but is currently waiting for a repaint.
In a few more posts, I will be up to date with the actual build status.

 

[Wasted wages]

Thank you for the reply Dirk!

After seeing several riggers broken in half at the radio box/ motor section, I have been glassing the hull for reinforcement. The thin glass cloth works well on the exterior and heavier weave cloth works well on the interior box to add strength. Your foam work looks nice,and I know exactly what type of foam board you are talking about.

Thanks for the tips!!

 

[Marty Slater]

hay Jerry you are not the only slacker around here!

 

[Grimracer]

MARTY!.. get back in the shop!..

Tite work Dirk!

Grim