3rd boat. flat deck 3-point hydro
 

I'm calling this operation:speed or bust.

Building this to be silly fast, so I'm using my Thunder Tiger .46 Pro on a Jettstream to power it.
3/16" birch 5-ply plywood, and some 1/8" birch plywood for the sponson/tub skin.
14" wide, 20" overall length. Sponsons are 2"w X 2"h X 9" overall length. Tub is 4"w X 17.5" X 1.5" deep at transom

I mocked up 1 hull but deemed it too big for the .46 - It was 18"w x 24" l so I made a smaller one. here's the two side by side:
Attachment 2237046
This is where I'm at right now; The foam is only temporary, but gives an idea of size since I dont have the sponsons cut from the plywood yet. As pictured with the foam, The hull weighs 1 pound 9 1/4oz. Its one ounce less without the foam. I'm hoping for less than 4lbs RTR, but we'll see. Going cheap on this one.
Attachment 2237047
Attachment 2237048

I should have the sponsons made today and get everything sanded and glued together. I have some mods to make to the engine stand, but I hope to be ready to glue later today.

RE: 3rd boat. flat deck 3-point hydro
 

I got mine in Depron ( 6mm ). I laid 1/32 ply on the top for strenght. The bottom of sponsons has 1/32 ply and the bottom of tub is also 1/32 ply. I used thinned epoxy on the ply for waterproofing. I have no water rudder but made an airrudder and used piano wire from servo to airrudder.. I haven't had it out as the hot weather, storms and rain and now moss. Always something. I sand the depron and used latex house paint which they say doesn't eat foam, wait and see.

RE: 3rd boat. flat deck 3-point hydro
 

The foam sponsons are only there for pictures. My final sponsons will be made of plywood. Probably 1/8" or 3/16" for the sides and aft parts with 1/32" for the skin on the bottom. My work area was inundated with sun so I quit working on it for awhile.. All I really have left to do is finish the radio box up front and make the sponsons and tub supports to get the control cables laid out.

This boat is water only. I think its an injustice to run a hydro on land. I'll be happy with 50mph on the water but I wont know for awhile. I think I'm on-par with coming in under-weight.

RE: 3rd boat. flat deck 3-point hydro
 

Getting closer to assembling it. I still have to make the servo mounts and run the control cables but its just about ready for epoxy. Without the sponson/tub skin on, the hull is about 2lbs. This thing should scoot pretty good with my TT .46, that is if it doesnt sink.

http://i153.photobucket.com/albums/s...IMG_0051-2.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Looks great! Tie a balloon to the top, won't sink,LOL!

RE: 3rd boat. flat deck 3-point hydro
 

Nice one.. I dont think balloons will play into my scheme here. I'm really thinking this thing is not going to float on its own with my .46 and pipe/full tank of fuel. It doesnt weigh more than 3.5lbs with running gear on it but I might have to make some modifications to the engine platform to give me more adjustability with where the engine sits to allow some weight transfer.. I think I'm going to get the control cables and servos mounted and then skin the sponsons/tub and float it in the bath tub and start piling weight on the engine stand and find out when enough is enough and find out whats going to work. A little trial and error and I might get this thing running.

RE: 3rd boat. flat deck 3-point hydro
 

How about contacting Self-Inflicted or even looking at his site and info he has typed cause you've put your heart into this project. You can't stop now, i said so,LOL!! ?, are you by any chance going to use pink foam inside the sponsons and cover with 1/32 ply? Why i ask is, years ago i built a 25" Cat of Jay Turner and used pink foam inside sponsons with 1/32 ply and worked great. That's when nimH were in play and added weight but i was a novice and only one boat site around at the time. Trial and error and just reading everything available to gain knowledge. Well, have a good day. BTW, Jays sponsons were 25" long and 2 1/2" deep and wide.

RE: 3rd boat. flat deck 3-point hydro
 

I'm not putting foam in the sponsons. They will be fiberglassed on the inside so they will be water tight. Hollow sponsons weigh less. The foam would only provide floatation if the sponsons/tub weren't water tight. Incidentally, I haven't put much effort I to this one. The overall design has proven to work well and go fast ( SI 3 boats ). I just dont have the money to buy one of his kits. ( I'm on that forum too ). This is a throwaway so if it doesn't float or go, I'm not out anything but time and free material.

I'm going to add 1/2" balsa strips for skin support in the sponsons and tub. I have to make modifications to the radio box to fit my hitec 645 servos, battery pack and Rx.

The 1/8" plywood I have wont make the bends necessary on the sponsons so 1/32" is the ticket. I'll have new pics up later today.

RE: 3rd boat. flat deck 3-point hydro
 

Sounds good!

RE: 3rd boat. flat deck 3-point hydro
 

Got a good chunk of the hull epoxied together. Servo mounts are done, radio box is halfway glued. Engine mount/center tub is curing right now. Once its cured, I'll mount the servos to run the control cables. Since I'm using Hitec high speed 645mg servos I had to enlarge the radio box a little bit to fit the big servos. I have had really good luck with these servos, So I'm slowly collecting a pair at a time for all of my cars (steering) and my airboats.

New pics will be up later.

Off to the hobby shop for some chunks of balsa, thicker fiber cloth, and a few other misc. items to finish this one. I am really hoping I can get it on the water to test next weekend.

RE: 3rd boat. flat deck 3-point hydro
 

Getting there...
http://i153.photobucket.com/albums/s...R/IMG_0060.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Picture of Depron

RE: 3rd boat. flat deck 3-point hydro
 

))))))))

RE: 3rd boat. flat deck 3-point hydro
 

Nice SI3-E. I would have bought an SI Kit if I wasn't broke. I'll probably order a .60 sized kit and put a pair of engines on it. I was gonna get a Jett 56lx for another project but I might settle for a pair of .40's or .46's.

For now, I'm gonna keep building hulls for my TT .46 until I get to 50mph or better. The TT is the fastest turning engine I have right now.

RE: 3rd boat. flat deck 3-point hydro
 

I like the Minnesota cut-outs on each side of the motor stand. BTW- i'll be reading the postings on your progress. I'll be in and out as i have lattice to put around deck and finish a Mono called Arpro 1, i completely revamped it.

RE: 3rd boat. flat deck 3-point hydro
 

I love Minnesota. It might get cold and snow, but its like no other place on earth.

Got the servos mounted, and have the cables ran the way I like. I dorked it and ended up breaking one of the clevises so I have to go pick up a pack of them tomorrow.
http://i153.photobucket.com/albums/s...R/IMG_0062.jpg
My own rudder creation. I used parts from an Aquacraft rudder assembly, and a couple pieces of brass. I made a similar rudder for my flatbottom and it works pretty well.
http://i153.photobucket.com/albums/s...IMG_0064-2.jpg
Here's the bottom view with the servos mounted.
http://i153.photobucket.com/albums/s...IMG_0066-2.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Actually it's a lot like parts of northcentral Russia, but I digress. That's a cool boat, and I am anxious to see it run.





.

RE: 3rd boat. flat deck 3-point hydro
 

This is going to be a mean machine !  :)  Bring it on!

RE: 3rd boat. flat deck 3-point hydro
 

I have never been to Russia, so I wouldnt know but I will go out on a limb and say Russia doesnt have nearly as many lakes as we do in Minnesota... nonetheless, I like it here.

Looking forward to posting videos of this little bugger running. Hopefully it runs better than my last hydro build.

I really hope so. Since my last hydro looked far better than it ran, I hope this one runs better than it looks since I'm scrimping in the "looks" department. I'm emphasizing light weight and high power. We'll just have to see if the TT has what it takes.

I am waiting to hear back on another engine - a SuperTigre S45 ringed. If I get it, I'll have another engine to build for......

RE: 3rd boat. flat deck 3-point hydro
 

Inside mating surfaces are glassed. I used 2oz cloth and Pacer Z-Poxy finishing resin to do the work. I didnt glass the entire inside because I'm trying to stay weight conscious. All I was really shooting for is a little extra strength and to keep the inside watertight. Next I'll add some balsa strips to the inside edges of the tub and sponsons for skin support. Once thats in, I'll skin it. I want to give the resin overnight at the least to cure before I sand it and put the balsa in.

Here's a pic..
http://i153.photobucket.com/albums/s...R/IMG_0339.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Almost done.. All thats left is mount the engine and fuel tank, antenna and radio switch, and skin the tub/sponsons.

http://i153.photobucket.com/albums/s...R/IMG_0342.jpg
I added a little "flair" with some American Cherry strips on the outside of the radio box and engine stand. This brings the wood specie count up to 3.. Once the skin is on, I'll start getting some polyurethane on it. Hoping to do some testing over the Labor Day weekend.
http://i153.photobucket.com/albums/s...R/IMG_0345.jpg

RE: 3rd boat. flat deck 3-point hydro
 

More pics of the progress. Just need to install the fuel tank and solder the cables and I'm done. Well, I have to seal it up with a few coats of finish but otherwise this is RTR. as pictured minus the fuel tank and fuel its RTR and weighs 4lb7oz. A bit heavier than I anticipated but it should still run out better than my Rigger. The sponsons are a bit oversize from my original plan, 1/2" wider and 1/2" taller. I think its gonna rip pretty decent. Engine is turning a 9x7 apc at 16,550rpm or so, and with another gallon of fuel it might see 17,000rpm. Got a few mods in order to free up another 1000rpm but that'll have to wait til winter.. I'm ready for some fun!

p.s. Dont mind the cat... she wouldn't leave me alone. [>:]
http://i153.photobucket.com/albums/s...IMG_0068-1.jpg
http://i153.photobucket.com/albums/s...IMG_0070-1.jpg
http://i153.photobucket.com/albums/s...IMG_0072-1.jpg

I left everything loose so I can pull it apart to finish it which I'll start tomorrow. I figure if I can get two coats on it a day for the next 4 days it should be good enough to tear it up Saturday. The finish I'm using for the last 3-4 coats will leave a nice flat finish which is pretty slick too. I am hoping to be seeing 45mph or better but would be happy to get a speed that'll actually register on the gps, and not have the gps laugh at me. (not like my rigger which ... goes 1.63mph.)

anyway.. I'll have pics with finish down in a couple days.

RE: 3rd boat. flat deck 3-point hydro
 

Don't mind the cat.LOL! Here's something that's funny. We have cats and we just put 2 sisters asleep at 19 years of age. Well , wife went to ARL and saw this white cat and come to find out it was raised by a man put he gave up and ARL got it. Well i was laying in recliner and up jumps LILLY and lays on my chest and touchs lips and marks my nose and fllows me all over. Ok, i was working on a boat and up she comes and puts both front paws in boat and looks at me as to say , lets get it done.I about fell off stool laughing so hard, i about split a gut. When i get busy, and really don't want her around like gluing or soldering in progress, i start the drill and she's gone. Sounds mean but burning hair doesn't cut it and epoxy in cats hair or paws doesn't help. Man it looks great!

RE: 3rd boat. flat deck 3-point hydro
 

Thankfully, Lucy my white persian stays out of my hair when I'm doing anything except taking pictures. Quite convenient. Anyway, everything is done on the boat except getting the clear coat on. I got the first coat on the whole bottom of the hull. Once its dry I'll coat the top. I hit the top and sides of the engine mount, and radio box cover also. Pretty much going to be one of those coat a side, dry, flip and repeat. I'll do that all week and try running it on Saturday. I certainly hope the effort pays off.

RE: 3rd boat. flat deck 3-point hydro
 

Great, i sand the bottom with 2000 wet/dry black sandpaper with water and sand lenghtwise and do make it slick. I just dip paper in a cup of waterand sand and dry with a towel. Man it sure does look nice. Now if you look close at the last picture of bottom, it looks like its ready to burn water. Just got that LOOK>

RE: 3rd boat. flat deck 3-point hydro
 

What I do to make it slick is use Commercial waterbase floor finish in a satin or matte sheen. When this stuff dries, its like a sheet of ice. Its nice and slick, no sanding required.

Now that I have some finish on it, the colors really pop now. The cherry and and antique maple looks really sharp against the birch. This boat I kept all of the edges pretty sharp. The only taper is on the rake of the tub and sponsons. The trailing edges of the tub (transom) and sponsons all have sharp edges on the bottom. I canted the trailing edge of my sponsons on the outrigger I built, but I dont know if that has any hindrance on performance since the engine doesnt make enough power to get the heavy rigger on plane. I think that one might need a .61 that'll turn some better rpms than the .46 can do.

I tested all of the radio functions before final tear-down and everything is adjusted to work decent first run. I only worry if the engine is too heavy and sinks the back end too much. Once I get a few coats on it I'll float it in the bath tub and see where it sits. I'll probably post new pictures then.

RE: 3rd boat. flat deck 3-point hydro
 

Albeit a few minor servo adjustments, this thing is RTR. I only put 5 coats of clear polyurethane on it.. It could probably use more but since I dont even know if its going to run I didnt want to waste more time and add more weight. I didnt have a chance to weigh it, I'll do that tomorrow.

http://i153.photobucket.com/albums/s...IMG_0073-1.jpg
http://i153.photobucket.com/albums/s...IMG_0074-2.jpg
http://i153.photobucket.com/albums/s...IMG_0075-2.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Pretty sharp!!!!!!!!

RE: 3rd boat. flat deck 3-point hydro
 

Thank you! I did a float test in my big jet tub and the back end sinks. I think if I hand launch it with a little throttle, it should stay up on top. If I get time over the weekend, I will shim the engine forward a little bit and see if that makes a difference. (I dont think it will change much) Hopefully it'll stay up and run out. I have my fingers crossed.

RE: 3rd boat. flat deck 3-point hydro
 

I hadn't posted the results of my initial test - FAIL. Through a twist of fate, I sanded the marks off on the engine plate of where I wanted to position the engine and forgot about the whole CG balance thing. Long story short - engine too far forward. nosedive. flip over cartwheel style. Made some adjustements to the engine stand, added styrofoam under the fuel tank shelf for a little extra floatation and the reslts so far are much better. She floats on her own, and the transom sits higher though still under water when sitting still. I tested the boat in the grass again with the engine shifted back and I'm much happier. Before, the back of the boat would lift off the ground when under power, now she scoots level and much easier I might add. I might try testing it out at the pond later today if I get time.

New pictures:
This is actually the rudder blade from the flatbottom that I modified a little bit. The solder joint between the rudder shaft and the blade was about 1 1/4" long, which made the boat "dance" side-to-side so I shortened the joint to 1/4"-3/8" instead. I already made this mod to the blade on the SICopy.
http://i153.photobucket.com/albums/s...R/IMG_0347.jpg
http://i153.photobucket.com/albums/s...R/IMG_0348.jpg
The rudder on the boat. (I am going to put a different rudder on this thing mounted higher when I can afford a speedmaster. rudder..) I used a nylon screw in the rudder bracket for a break-away.
http://i153.photobucket.com/albums/s...R/IMG_0353.jpg
Full Frontal
http://i153.photobucket.com/albums/s...R/IMG_0351.jpg
I need to find a tiny Minnesota Wild hockey sticker to put under the Minnesota cutout.. :lol:
http://i153.photobucket.com/albums/s...R/IMG_0350.jpg
I don't normally like stickers on my rides, but I couldn't help these two..
http://i153.photobucket.com/albums/s...R/IMG_0352.jpg
A sort-of bottom picture
http://i153.photobucket.com/albums/s...R/IMG_0356.jpg
Engine/Fuel Pump. (I added a return line because the regulator on the pump couldn't be dialed back enough to prevent the engine from flooding. Added benefit is the mixture doesnt change much from full tank to empty tank except for air bubbles at very low fuel levels. )
http://i153.photobucket.com/albums/s...R/IMG_0349.jpg
http://i153.photobucket.com/albums/s...R/IMG_0354.jpg

This engine is a little picky on fuel tank placement. I could probably get the engine to run fine without the pump and keep the tank below but I like the more consistent fuel mixture. I need to replace the O-rings on the Low speed needle valve before I re-test it, The low end and midrange was a little temperamental the other day.

RE: 3rd boat. flat deck 3-point hydro
 

tim...just studying your set up for a 3 point hydro...i am about to embark on this type of airboat myself...i have a tt60..what length and width would you suggest..looking at your hull size i was thinking of 18 x 24 ..keeping in mind the kit of selph is 29" long..i alsowish to make the engine mount slide back and forth so i can adjust the cg .. i think that is very importent i have a big swamp buggy and i cant adjust the cg without putting a heap of lead on it...it drags its rear end along puts the rudder mount under water and that slows it down to much...your thoughts much appreciated...bob

RE: 3rd boat. flat deck 3-point hydro
 

I am so sorry I never saw this post, Bob. Which SI3 is 29" long? The .25 size?

I have a BSB now as well, mine being extremely bow heavy. It needs to be torn down and rebuilt.

RE: 3rd boat. flat deck 3-point hydro
 

I decided to dust this thing off and tear it down to rebuild it so it will float, and maybe even run yet this year. Its been on the shelf while I run the snot out of my Kamikaze's.

Tore the skin off the bottom to make the center tub deeper, to aid in floatation. 1/32" plywood removed:
http://i153.photobucket.com/albums/s...R/DSCN0695.jpg
Balsa stringers added, making the transom 3/4" deeper than it was before, with a lighter taper to the bow.
http://i153.photobucket.com/albums/s...R/DSCN0697.jpg
Stringers glued on, and bulkhead spacers added, all balsa.
http://i153.photobucket.com/albums/s...R/DSCN0699.jpg
New Keel skin, made myself from 3/4" American Black Cherry. 4 strips 3/4" wide, 1 strip 15/16" wide. I used 4 small strips of cherry and epoxied them to the 5 strips to make one sheet out of it.
http://i153.photobucket.com/albums/s...R/DSCN0704.jpg
The skin strips are 1/32" thick and the 4 support strips are 1/16" thick
http://i153.photobucket.com/albums/s...R/DSCN0705.jpg
http://i153.photobucket.com/albums/s...R/DSCN0706.jpg

Waiting for the epoxy to cure, and I'll upload pictures of the skin on the hull.

RE: 3rd boat. flat deck 3-point hydro
 

Bottom skin is on and curing. Couple pics of the modification. The outside of the tub will get a thin skin to cover and seal the balsa.
http://i153.photobucket.com/albums/s...R/DSCN0707.jpg
http://i153.photobucket.com/albums/s...R/DSCN0708.jpg
http://i153.photobucket.com/albums/s...R/DSCN0709.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Here is the bottom skin and the little skirt sort of thing I used to cover the balsa. I just used a leftover strip of cherry.

http://i153.photobucket.com/albums/s...R/DSCN0711.jpg

RE: 3rd boat. flat deck 3-point hydro
 

tim...good to catch up with you...i am also well under way with a small 3 point...i am very happy at the moment..the only real change i made was i inverted my tt46pro and made my eng tower to slide back and forth so i could adjust the cg o the boat...i have a 31inch dumas swamp buggy..i had a 60tt on it and it went great..i put a tt90 on and it went very well but it did go with its nose in the air...that kit has no provision to move the eng tower to change the cg...i bought the 60 pland of ceph and hope to start the large size soon..but i wish to try the small one first..lookin for anty problems..i have a boating friend who is into hydro racing big time( not air boats) and he has been helping me...i will put up some pics soon as i get organized..i have been away for a whle ..now its time to get back into it....bob

RE: 3rd boat. flat deck 3-point hydro
 

Good to hear from you, Bob. Glad to hear you're building. My TT 46 is a great engine. I had mine inverted on another boat with a fuel pump but it didn't like that very much. It runs better without the pump and upright.

I'm going to test float my 3-pointer tonight. I'm really hoping I don't have to chop the engine stand down to save weight, but I will if needed. The stern sank some before, and in some of the update pics above, you can probably see why. If it floats on its own well, I'll pile weight on until the transom drops below the water line to see how big an engine I can run on it. Hoping the Enya 30ss works just right.

RE: 3rd boat. flat deck 3-point hydro
 

Some more progress on my failed 3-pointer... Cut the old engine stand off and made a new one to mount in its place. The new one is a couple ounces lighter and has a small amount of adjustability added to move the engine fore or aft a little if needed.

Bottom skin with 2 coats of resin and 2oz cloth, and polyurethane on top for a smooth and slick finish.
http://i153.photobucket.com/albums/s...R/DSCN0715.jpg
New engine stand, with Enya 30SS mounted up.
http://i153.photobucket.com/albums/s...R/DSCN0714.jpg

RE: 3rd boat. flat deck 3-point hydro
 

Love the timber work mate, keep the pics. coming!

RE: 3rd boat. flat deck 3-point hydro
 

Thank you kindly, Oz! I've been working on this thing here and there. Since it will float now, I'm swapping electronics from another boat to maybe test this thing out. I have the servos installed but I have to fashion a way to cram a 4-cell Rx pack in the cramped radio box. If I can get the radio box buttoned up and find my spare fuel tank, I will go to the pond for test runs. A re-maiden if you will. I need to find out if the engine will have enough thrust to pull it. The boat weighs 2 pounds 14 ounces RTR so I hope I get 3-4lbs of thrust minimum from the .30 engine. My .29 is 2000-3000rpm stronger on the same prop than the .30 but that's running a full tuned pipe. I don't think this hull will take to the long pipe because the hull is so small. (20"L x 14"W). I also have a mousse can I'm going to modify to use as a muffler that's half the weight of the .46 muffler I currently have on the .30.

More pictures will come later.