Kep's 21 Freebie Outrigger PDF template drawing

[Niklas Edlund]

I just made a new blogg and uploaded some detail shots of one of my 2009 spec Kep's riggers.

-> http://ne-stuff.blogspot.com/2009/05/keps-21-09-pics.html

And if you missed the other "first-test-of-09-blogg", here's that link...

-> http://ne-stuff.blogspot.com/2009/05/first...keps-21-09.html

 

[Ron Zaker Jr]

I just made a new blogg and uploaded some detail shots of one of my 2009 spec Kep's riggers.
-> http://ne-stuff.blogspot.com/2009/05/keps-21-09-pics.html

And if you missed the other "first-test-of-09-blogg", here's that link...

-> http://ne-stuff.blogspot.com/2009/05/first...keps-21-09.html

Very nice craftsmanship! Oh and maybe unwrap that FASST RX, they like to breathe.

Ron Jr

 

[Niklas Edlund]

I just made a new blogg and uploaded some detail shots of one of my 2009 spec Kep's riggers.
-> http://ne-stuff.blogspot.com/2009/05/keps-21-09-pics.html

And if you missed the other "first-test-of-09-blogg", here's that link...

-> http://ne-stuff.blogspot.com/2009/05/first...keps-21-09.html

Very nice craftsmanship! Oh and maybe unwrap that FASST RX, they like to breathe.

Ron Jr

Thanks Ron, So far no heat issues with my FASST receivers but then we dont get too high temps over here.

 

[dwilfong]

well after fighting with my rigger and putting it aside for a time to re group. I finally got it up on pipe and running strong with a H7 to day. This is my first rigger and wow it felt great when it got on pipe and lit up.

Ended up putting a used MAC 21 in it with a speed master carb, got the 3280 pipe at 7 3/4 so far.

This is going to be a blast to mess with now. The fun has just begun.

David

 

[Niklas Edlund]

well after fighting with my rigger and putting it aside for a time to re group. I finally got it up on pipe and running strong with a H7 to day. This is my first rigger and wow it felt great when it got on pipe and lit up.

Ended up putting a used MAC 21 in it with a speed master carb, got the 3280 pipe at 7 3/4 so far.

This is going to be a blast to mess with now. The fun has just begun.

David

Sweet.

Twentyone's can be head-scratcing for sure before you get the hang of it.

/Niklas

 

[dwilfong]

well after fighting with my rigger and putting it aside for a time to re group. I finally got it up on pipe and running strong with a H7 to day. This is my first rigger and wow it felt great when it got on pipe and lit up.

Ended up putting a used MAC 21 in it with a speed master carb, got the 3280 pipe at 7 3/4 so far.

This is going to be a blast to mess with now. The fun has just begun.

David

Sweet.

Twentyone's can be head-scratcing for sure before you get the hang of it.

/Niklas

Well found the weak spot in my build already. Used carbon rods and tube for the booms. The rods came lose in the sponsons.

When I built the sponsons I just drilled a hole and epoxy them in.

To fix I am cutting a 3/4 square hole and inserting a 3/4 hard wood block in the hole. It will fit on the top surface and go all the way to the far side.Then I will drill the hole for the rod. Be strong like bull now.

Can adjust the position of the rods in the sponsons so I will not need so many shims now to make the top flat. Will also sand the bottom to get the attack angle closer to what I want.

Head-scratching more like head- banging on a brick wall :blink:

I'll get it if it's the last thing I do :angry:

Building from scratch is so much more rewarding than going with a boat that is already figured out you learn more by making all the mistakes.

David

 

[Niklas Edlund]

Hi David,

What kind of foam did you use as cores in the sponsons?

/Niklas

 

[JeremyEdge]

How much would someone charge me for the matrials and the build of this hull.And would any one on here do this for me.

Thank you,

Jeremy

 

[Jim Caldwell]

I've never had any luck just epoxying the tubes in foam either. Now I always run them all the way thur and sand them flush with the outside and I've already crash tested it and it works!

 

[dwilfong]

Hi David,

What kind of foam did you use as cores in the sponsons?

/Niklas

Niklas

Used some of the pink foam that I got from Boris same stuff in Lowe's. Got some blue from a job sight last week going to try it on the next build.

Doing it with the blocks will add some weight but it will never fail again.

David

 

[dwilfong]

How much would someone charge me for the matrials and the build of this hull.And would any one on here do this for me.

Thank you,

Jeremy

Jeremy

Believe me if I can build one any one can. This was my first boat build and it is not as hard as you might think.

Check out Niklas build tread and study it. It was very helpful with the build.

David

 

[shoboat]

Boat Builders,

Just another idea on sponsons: try contest balsa wood

and drill it out to lighten it up and then skin it with

1/32" ply or 1/16" ply whatever you are comfortable with.

This does make very strong and light sponsons. Another

idea that works well if you are using foam is to piece

a section of wood front to back in the center of the sponson

so the boom tube has more support in the middle of the

sponson.

David,

I would start with 4 degrees AOA on your front sponsons and

adjust from there. I run 4.3 degrees on some of my 21 hydros

and with the correct strut adjustments it does not blow off the

water at 70 to 80+ MPH. I think an H-7 is a lot of propeller to

start with on a new 21 hydro. H-4,H-5,and H-6's are better to

start with in my opinion. Octura 1445's and 1450's are great

places to start also, as they launch well and throttle very well

off the corners. I just caution you on too much cup, as it does

kill RPM in the engine and pipe set up. I was recently out

testing a new 21 hydro at 86 MPH with a 1650 with very little

cup and about the same amount of C.O.B. pitch.

Thanks For Reading Fellas,

Mark Sholund

 

[Niklas Edlund]

Hi David,

What kind of foam did you use as cores in the sponsons?

/Niklas

Niklas

Used some of the pink foam that I got from Boris same stuff in Lowe's. Got some blue from a job sight last week going to try it on the next build.

Doing it with the blocks will add some weight but it will never fail again.

David

Thats the issue with using expanded polysterene as cores - there is almost no strength in the foam so to speak. As soon as you get some sort of force applied on the tubes or turnfin etc the foam can colapse. Its just a shame that the right stuff foam cores are not so easy to get hold of. The right foam for outrigger sponsons is cross-linked PVC foam such as Divinycell H80 (H60 can be used also) and Airex C70.75 (C70.55 can be used also) - same material different manufacturer. It's an outstanding material to be used for foam cores. Its many times more expensive then polysterene but what does that matter when you spend hours making your sponsons, right?

With these foams its perfectly ok to epoxy in the carbon rods - thats what I do. And when you get the hang of it its easy to use CA glue and kicker and you can skin a pair in much less time then with epoxy.

If you "must" use expaned polysterene foam (such as roof insulation) I would strongly suggest you add additional strengthening pieces around the tube holes and turnfin mounts etc or continue with the rod/tube all the way through on the outside of the sponson. The "only" strenght in that type of sponsons comes from the plywood surrounding the foam.

 

[dwilfong]

Boat Builders,

Just another idea on sponsons: try contest balsa wood

and drill it out to lighten it up and then skin it with

1/32" ply or 1/16" ply whatever you are comfortable with.

This does make very strong and light sponsons. Another

idea that works well if you are using foam is to piece

a section of wood front to back in the center of the sponson

so the boom tube has more support in the middle of the

sponson.

David,

I would start with 4 degrees AOA on your front sponsons and

adjust from there. I run 4.3 degrees on some of my 21 hydros

and with the correct strut adjustments it does not blow off the

water at 70 to 80+ MPH. I think an H-7 is a lot of propeller to

start with on a new 21 hydro. H-4,H-5,and H-6's are better to

start with in my opinion. Octura 1445's and 1450's are great

places to start also, as they launch well and throttle very well

off the corners. I just caution you on too much cup, as it does

kill RPM in the engine and pipe set up. I was recently out

testing a new 21 hydro at 86 MPH with a 1650 with very little

cup and about the same amount of C.O.B. pitch.

Thanks For Reading Fellas,

Mark Sholund

Mark

I started with the H4 you did for me and it jumped right up on it. So I had a H7 and said lets just see. Well it didn't jump right up on that one! messed with the needle and it came on pipe to my surprise and lit up. WOW what a rush it was screaming and looked like it would speed up in the corner's. But if it fell of pipe it would take time to get back on.

Just getting the hang of the boat right now.

Tried a grim racer 42x66 and it liked it staid on pipe.Also liked a 1640.Have a 1445 and 1450 to try. Will try the 1650 also and see what happens.

Right now just want to get it stable so I can break in the RS-7 sleeve I got from Stu.

When I get closer I get with you to do a prop.

David

 

[shoboat]

David,

1650 is going to be a lot of propeller for that set up.

The H-7 just needs a little less cup and about 1 mm reduction

and you should be alright. The 40 and 42 mm are a little small

for that set up.

Thanks,

Mark Sholund

 

[Neil LaGarry]

Niklas,

Back when the Dumas Hawk was the hot rigger the Styrofoam core was softer. The same white stuff that comes inside any shipped box ,TV radio,electronics . It was used on the rear sponson 1/2" thick When the epoxy cures rock hard.

 

[Niklas Edlund]

Niklas,

Back when the Dumas Hawk was the hot rigger the Styrofoam core was softer. The same white stuff that comes inside any shipped box ,TV radio,electronics . It was used on the rear sponson 1/2" thick When the epoxy cures rock hard.

Yes, but the styrofoam is not so good of a core anyway - at least if you dont strengthen the stress areas.

If you put enough force to it it will brake inside your sponsons and its very hard to repair.

Another problem (I think) when doing rear sponsons - if you use a too soft a foam its tricky to sand the pointy noses on the sponsons as there is so much give in the foam. That is also the case if you use H60 or C70.55 - they are slightly too soft for small sponsons... I would do as Mark suggested, use some strengthening "wood" pieces or use balsa as cores (if you cant get hold of Airex C70.** or Divinycell H** foams). At least the rear sponsons could be made of balsa entirely and only the lower part skinned to get the edges square and sharp.

H7: yes, thats a lot of proeller for a Kep's rigger with rear sponsons and exposed running gear. If you would use a rear ski then its a completely other ball game though. The 1650 is way too much also. The normal Sholund props we use with our well trimmed Kep's riggers is H6 with about 3.4-3.6 cup.

Mark: The Kep's Freebie would be running really light on the front with 4 deg AoA - at least in race waters. But if you run on your own on flat water it could be set-up with 4 deg I would think (but we never test them like that). I haven't measured it lately but I think around 3+ deg is more what the Freebie is best raced at. My latest version do use more built in AoA on the running surfaces though without being too much.

 

[Neil LaGarry]

Niklas, yes I see your concerns over stress. Here is a old Hawk. Where the sponson is made of balsa, the 2 small blocks that hold the boom tubes are made out of balsa .The outer skin is 1/16 birch ply

 

[dwilfong]

The repair was not hard at all. Cut out a 3/4" square piece with the boom centered in the middle with a razor knife. The top of the piece was the top of inside sheet of the sponson. Then used a box cutter to cut the foam all the way to the far side. Then took a 3/4" mahogany stock and epoxied it in and cut off flat. Then took carbon fiber sheet and covered the in side surface of the sponson. Drilled new holes and epoxied in the old rods. This should tie the turn fin and boom tubes together real nice.

After seeing Marty's boat run and talking with him. I am going to try 3.2 on the right and 3 on the left for the AOA. With the tops flat. This repair gives me a chance to fix bad placement of the tubes from the original build. Have a better under standing of the placement and what it will do.

David

 

[dwilfong]

Niklas,

Back when the Dumas Hawk was the hot rigger the Styrofoam core was softer. The same white stuff that comes inside any shipped box ,TV radio,electronics . It was used on the rear sponson 1/2" thick When the epoxy cures rock hard.

Yes, but the styrofoam is not so good of a core anyway - at least if you dont strengthen the stress areas.

If you put enough force to it it will brake inside your sponsons and its very hard to repair.

Another problem (I think) when doing rear sponsons - if you use a too soft a foam its tricky to sand the pointy noses on the sponsons as there is so much give in the foam. That is also the case if you use H60 or C70.55 - they are slightly too soft for small sponsons... I would do as Mark suggested, use some strengthening "wood" pieces or use balsa as cores (if you cant get hold of Airex C70.** or Divinycell H** foams). At least the rear sponsons could be made of balsa entirely and only the lower part skinned to get the edges square and sharp.

H7: yes, thats a lot of proeller for a Kep's rigger with rear sponsons and exposed running gear. If you would use a rear ski then its a completely other ball game though. The 1650 is way too much also. The normal Sholund props we use with our well trimmed Kep's riggers is H6 with about 3.4-3.6 cup.

Mark: The Kep's Freebie would be running really light on the front with 4 deg AoA - at least in race waters. But if you run on your own on flat water it could be set-up with 4 deg I would think (but we never test them like that). I haven't measured it lately but I think around 3+ deg is more what the Freebie is best raced at. My latest version do use more built in AoA on the running surfaces though without being too much.

I put the ski on with the rear sponsons but it was bouncy in the rear in rough water so I took the ski off. I am going to try a v shape ski set up with a small flat in the back and see what happens.

David