Step by Step Building a hydroplane / MRC is up and running

[blueskyracer]

Basically the areas I have to sand is where stringers attach to the coaming walls and such where there is epoxy squeeze out. Dave is right and what I do is glue on these stringers that attach to the side walls first and make sure all the cross ribs butt up tight in the coaming wall holes to these stringers. The big planning and sanding areas are in the sponson where you have to shape the edges to the matching sponson angles.

Way earlier I said and showed everything getting leveled and squared. It is a criticle step. I do block sand the last couple feet before the bottom just to make sure any high and low spots are gone and to rough up the surface for good glue adhesion. I use a very strait 2x4 with 50 grit paper glued to it. I have two different lengths for the step in the bottom.

[DeanFHobart]

Carbon Transfer Paper

Yo,

Carbon transfer paper in large sheets is available from Glen-L Plans in California.... you can order on line...........

Black Transfer Paper 2 foot x 16 foot.......... $7.95.

Good Luck,

Dean.............................................. ...................

Yes I know the plotter is good, but unless you have the toothed wheel to keep the paper registered, especially on long plots it can slip and the paper is also affected by changes in humidity.

You are right, I checked office depot and office max on line for carbon paper, no luck. However, I buy an amazing amount of supplies and tools from Amazon.com, and the carbon transfer paper in rolls looks especially useful if you scroll down the list. It is a pain to line up a row of letter size sheets for long lines and the carbon can be used over and over again.

http://www.amazon.com/s/ref=nb_sb_ss...x=carbon+paper

http://www.amazon.com/s/ref=bl_sr_ki...dtextbin=SARAL

[Bill Huson]

yep . . .

Would it be just as easy to cut and plane all your stringers at one time prior to installing them ? If you cut all your cross frames, and stringers at once, the heights and widths etc will all be indentical. Then if it is off after installing, it means your level and straight is not correct, or the cross frame holes in the cockpit are not cut out correctly. I found that if you are not using pre-cut from the lumber company, this works well. Get your jig and table level, and then square everything in the jig and double check level. If you plan 3/4 x 3/4 stringers all at once to get final dimensions, it should all be perfect with no additional sanding or planning needed.

But by all means, do it the way you want, that is the fun in building a boat. You tweak the build to suit your style. There is no wrong way to build it, just your way.

Did all that - ran all my stringers through a surface planer. But after attaching them there was always 1/32" drift or whatever, so I used the router. Others use a sanding block, like I did before the router, or just slapped it together and did the ol' stinky-stone deal later on.

I mention the router jig `cause the Montana crew may go into multi-boat production and any time saving power gizmo would come into handy.

[Mini Max]

I would suggest that you not run battens through a planer. Its a little academic because many small shops don't have one.

The feed roller will crimp the top fibers because the pressure is set up for a wide board not to slip. I have seen small battens come out the planer like a banana. The wood aircraft construction rules so state also.

[blueskyracer]

I say whatever works for you is good enough. It just needs to be flat for the last 2 to 3 feet.

[blueskyracer]

I mention the router jig `cause the Montana crew may go into multi-boat production and any time saving power gizmo would come into handy.

Thanks Bill for the thought but business is so slow that I don't think it will be a problem for a long time. According to a lot of posts on HR outboard racing is doing a slow death. But we are going to have fun till the end.

[blueskyracer]

these are the photos showing the angles on the sponson that I am planning in for the plywood along with my two sanding blocks. With the tunnel within a tunnel you need two different length sanding blocks.
If you notice the squiggle lines I put on the stringers I sand with the blocks till they start disappearing and then I know it is flat all the way across in that spot.

[daveracerdsh]

Stringer wood

What kind of wood are you using for stringer material? Can't tell from pics.......

[blueskyracer]

What kind of wood are you using for stringer material? Can't tell from pics.......

Most of it is Engleman Spruce Lodgepole

[blueskyracer]

Here is the latest progress. All angles are cut and the plywood first sheet has been test fitted. Note the angle in the leading edge of the plywood for the second sheet. Also have finished the mold for the laydown ramp.

[blueskyracer]

few more

[blueskyracer]

I would like to add that we just sold our first set of plans overseas to a nice guy in Sweden. Yes they were C Mod plans! He sent pictures of some of his work and it is fantastic. He cuts out parts with a waterjet. There is not anything he can't cut. Hopefully I can get him to post some on this forum.

[Mini Max]

I might suggest you do a test on the length of the plywood scarf you show here and earlier. A 12:1 used to be standard but commonly now 8:1 is the norm.

The Gouegeon's sells a "scarfer" which is a jig that secures to a skill saw for cutting scarfs. I used to have a jig for my shop that allowed me to cut scarfs on my table saw running the plywood on end. If I remember correctly the angle is 7 1/2 degrees to get 8:1

I also had a scarfing table like the one I googled here below except that the table end had a box under it with a grainger car wash vacuum motor attached. The top surface at the end for 12'" had small holes drilled. When the saw was turned on the vacuum also started and held the plywood flat while cutting. http://slipperlaunch.net/scarffing%20jig.htm

Chris Hodges (f-1 capsule inventor boat builder supreme) built a couple boats for me some years ago. He must have thought I was queer for trying to rub his head to gain some of his Mo-Jo. His scarf glue - clamping jig used cheap hydraulic jacks in a row for clamp pressure. I never did ask him how he was cutting them, but the results were flawless.

[blueskyracer]

This post is to show that it is not that hard to build a boat and not scare folks away. Scarf joints can be done easily by hand if you take your time and for the 3 required for a boat a fortune for tools and the space required to store it is not necessary.

On the scarf cut make sure to set it up so that the angle is like in the picture so that water flow cannot ever catch the edge.

[blueskyracer]

Here is some of Martin's work over in Sweden. And to think the stuf in Black is only the jig work!!