First tunnel build

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Michael Villeneuve

Well-Known Member
Joined
Oct 12, 2019
Messages
87
Hey guys,
I need some advice on a tunnel build. It's my first ever build so bare with me.
For the floor of the center hull, should there be an angle on there or is flat okay? Basically I built my jig flat out of MDF but I was wondering if a flat bottom is okay to do?

Thanks for the help
Mike
 
Micheal,, the question is not fully clear.. having said this..Flat (Parallel) is NOT OK.. well.. at least the entire way. you can add a break OR.. run a positive AOA.. but it can not be parallel with the water.

So.. to answer.

The tunnel roof should have, at some point along its length, a positive angle in the direction of flight.

Grim
 
Last edited:
Grimracer said:
Micheal,, the question is not fully clear.. having said this..Flat is NOT OK.. well.. at least the entire way. you can add a break OR.. run a positive AOA.. but it can not be parallel with the water.

So.. to answer.

The tunnel roof should have, at some point along its length, a positive angle in the direction of flight.

Grim
Click to expand...

Sorry grim I'm new to this and am not too familiar with the terms yet.
Yes what I mean is the "roof", the part underneath the hull.
So next question then would be, could I be running a AOA all the way down the center?
Basically I'd be doing the "roof" of the center flat, but have an AOA once the sponsor are installed?
This way the center section would Not be parallel with the water.

Thanks
 
Yes.. your assumptions are dead on.. as long as its not flat (parallel).. or negative with the water

VS1 = 1deg..
Nemesis = 1/2 deg.. (however this boat has lift elsewhere)

The best angle is debatable!

Keep us posted.

Grim
 
Last edited:
Yes, use your flat MDF board for the center section which will make the roof flat (same as Dragon, VS1 and Nemesis). FYI Jerry Dunlap and others build a "rocker" into their center sections so the tunnel roof is not flat.

Mike is spot on about angle of attack (AoA). But that is set when attaching sponsons to center section.

Cheers
Kris
 
brad nichols said:
Are you building a kit
Click to expand...

No is I'm scratch building off of pictures and measurments I was given. I do have Plug for sponsons which i will be using but I'm building the rest from scratch. hoping it will all work out.
Currently have 4-5 small pieces left to cut then i will be gluing the center section together.

Mike
 
Alright so here is where I'm at now. Again this is my first ever build so i do restart a lot (3rd time now) . Forgive me for my lack of terms, I'm still getting familiar with all of it and I'm french so that doesn't help.
This is the center hull based off of pictures from a boat that used to run in my area.
The sponsons are in fiberglass. I still need to make sure everything is square and that the gaps and meeting points between pieces are not too big before I start gluing anything. I'm cutting most of it with a scroll saw which really helps and makes it faster but I'm still getting used to it. My next step i believe is going to be cutting out "indents" to glue stringer along the center, top and bottom edge to glue the floor and deck to.
If I'm skipping a step or missing something please let me know. I'm on my own for this so any tips or help is greatly appreciated.
IMG_20191115_221528.jpg IMG_20191115_221539.jpg IMG_20191115_221559.jpg
 
Looks great so far. Your transom will want to be about 2 or 3 layers.

How long are your sponsons?

Your English is much better than my French!
 
IMG_20191119_204645.jpg Thank you Kris!
So my sponsons are 26 inch long. as for the transom, i was thinking of adding a pieces of 1/2 inch plywood to the inner part of the center hull only. (where the engine would be bolted) Would that be enough or i need to reinforce the entire length of the transom?


Thanks for the input Brad. what type of foam would you be using for this? I will try to get my hands on some tomorrow.
 
I will let the other WOF guys answer the foam question :)

You only need to do the center part where the engine bolts to. BUT doing the whole length will help with rigidity of that whole part. A piece of hardwood on the front also helps IMO. Once the deck is glue on the whole thing will stiffen up nicely, leave it clamped to you setup/flat board for as long as you can while the glue dries fully.

Kris
 
Good morning Michael..
Looking good so far...the foam we speak of is a building insulation foam..XPS
extruded poly styrene....its sold at most any home improvement store....beaded foam will also work but a more work is required...the rear transom ..I would add 2x what you currently have..looks like 3mm currently....just glue 2 more and you will be good..the second pic...you can also see the transom thickness20190612_142758.jpg 20190713_172144.jpg
 
perfect I'll get to work on that today. I used 1\8 plywood for these parts so I will add 2 more to the transom today.

Thank you guys, it makes it much easier when you can ask question and get tips on a forum.

Mike
 
Any time ...
You can also reference my "j.d. wof tunnel build series...I just finished the boat and need some warm weather to try it out...just ask away.
Iam interested in the fiberglass sponsons in you pic....who and where did those come from...
 
Robert, I will be reading your build thoroughly, congrats on finishing It. Up here the lakes are starting to freeze so I wont be able to test anything until end of April!
As for the sponsons, I got them from a guy in my area that used to work at my late grandfathers hobby shop. he used to build a lot of boats for our local club. His name is Francois. He made those years ago and built only 2 boats with them but they were the fastest boats around. He was nice enough to give them to me. as he said, it's going to be a lot easier for me to make the sponsons from those molds and get them spot on instead of scratch building them.
 
The Pink or Blue foam works good But the white is a lot lighter and not as dense from Lowes or Home Depot. You will have enough for 10 or more boats, maybe go by a construction site and ask as the re mite be a piece in the garbage.

Brad
 

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