new guy looking for ideas

[3cells]

Hey Corky,
Thanks for the input! The terrain down here is mostly sand, mixed with occasional oyster-beds and gators, so I'll just run it as-is, see how it works. I'm just finishing up the dings in the sides, repairing the glass on the edges under the t-rails where the rivets all either ripped through the material or expanded the holes so much the T-rails were detached. Next are the new stringers, using 1x4 spruce, some primer, & finally some epoxy paint. Then I get to the rigging! hope I can get it back out on the water quick when I actually swap hulls. There's still some trout in our area, and the wife really wants to try flounder gigging at night!

[3cells]

latest progress,
holes repaired, gussets reinforced, stringers replaced, hull stripped and refinished, new transom rail, new anchor u-bolt up front, & rebuilt the standing deck, with scuppers. just need to recoat the inside. Had to stop for a couple months, as our band tours till Sept. when I hope to have a new prop, & build the rigging, Much as I hate working fiberglass, this has really been gratifying!

P.S. Almost forgot, new motor, Generac 32 HP V- twin, thanks to a tip from yamahauler!! Going direct drive, will see how she runs, keep you all posted when I get back in Sept!!

[yamahaulerG1]

Looks good and light weight. I likeThe way you did the front deck so the water will go out the side instead of in the boat.

[3cells]

yeah, with as little flotation (none) as these things have, I want every advantage I can get! I also added some poly non skid granules to the finish on the deck. I'm thinking of filling in the spaces between the stringers with expanding liquid flotation foam, then decking over with something light, but I want to run her first to see if it can handle the extra weight. Thanks again for the tip on the generator, wish I could be working on it now, but we're on the road till sept. we're up in Anchorage Alaska right now, close to barts neck of the woods, (kinda, if you have an aquaplane) Cheers!!

[Corky]

Nice work. Looks great !!

[3cells]

It's been a while, life gets busy, projects get delayed, etc. etc. but here's the latest!
I'm tired of making all this stuff out of steel, and watching it dissolve in a year from salt water. So, after some research, I bought an Arc Pig HF converter/stabilizer, & an Argon tank and regulator that enables my old Forney stick welder to do a passable imitation of a tig welder. Now, I'm on a learning curve to make passable imitations of Tig welds... It's definitely an art form, fortunately, I'm good with a grinder! I couldn't afford stainless, so the new rigging is schedule 40, 3/8" (ID) aluminum, which is comparable to 1/2" EMT, in size and strength, and is lighter. I'm loving being able to fab aluminum and stainless, here's a couple pictures. I'm giving up on the Rockwell JLO/ Cuyuna on the heavy fiberglass Jon-boat. I'll probably sell the hull, and make an aluminum build later on, to put the JLO on. I'm hoping the generac 992 will be able to get 2 of us and this rebuilt fiberglass air-boat hull on top of the water.

[3cells]

more of the rigging

[3cells]

now I'm working on the motor, made some mounts out of SS bolts and old tire material, seems rock solid. Does anyone know how much of the factory shroud to leave on? I'm leaving the front with the fan/magneto cover in place, to utilize the forced air cooling to the heads, and thinking of maybe some scoops for the sides, as I'm going to be sitting directly in front of the motor, blocking airflow.
I wonder if I'll need to change the main jets, since I've removed all the governor/regulator/circuit board stuff in favor of just the bare bones magneto ignition, and the start/on/off switch, I had to remove a solenoid that shut off/ controlled the fuel flow to the main jets.
Also, any ideas on exhaust? The exhaust ports face the blade, so space is critical, I made a couple SS manifold flanges with 90 degree ells, and have a couple 12" straight thru mufflers,( more like the old glass packs) that I'm thinking of welding directly to the ells, pointing to the sides kind of like dragster straight pipes, does this motor need more back pressure than this? The mufflers have 0 resistance, minimal baffling

[3cells]

also... been saving the coins for a prop, the guy I talked to at Comp. aircraft is steering me to a 4 blade 48" old style ultra prop. It seems kinda small. I know Yamahauler is using a 3 blade 52" on his direct drive generac 992. I'm basically doing the same setup, but on a heavier fiberglass hull, also direct drive. The generac tops out at 3600, so I hope I can do without the reduction, Any ideas on size and blade numbers?

[3cells]

redneck motor mount

[3cells]

the old Forney with converter, works well for what I'm doing. The manual that comes with the Arc Pig is hilarious!

[3cells]

This is the only original shroud I'm leaving on,(red part visible on front) I removed the wrap around pieces on the back/prop side for more exposure, less restriction. It also holds the choke and start switch, & keeps the magneto/fan protected. Unfortunately, it's directly behind my seat, with about 4" clearance. I'm concerned about airflow. The onboard fan was designed with stationary use in mind & I'm hoping it provides enough. I'm considering adding some discreet scoops on the sides, funneling air to the back/prop side of the heads.

[Corky]

Good work...That exhaust is close to the front of the prop in it's current form..Probably too close..Not too many choices on what can happen there...Either split them and route them away on each side or get that cross tube in closer to the engine which might generate some heat around the back of the heads...I've seen them done both ways..
The small air deflectors might not be a bad idea to help redirect some airflow over the head's fins if you think that shroud isn't going to get it done...

[3cells]

Thanks for the comment corky! Funny you should mention split exhaust, I just finished fabricating 2 stainless elbow flanges to do just that! I have a couple straight tube type silencers, that I might weld directly to the ells, still trying to find out if the motor needs some back pressure, or if I can go that direct, any ideas? I also wonder if the end of the exhaust needs to extend beyond the blade tips if there's nearly a foot of space between. possible negative effect of heat or vapors? I'm going with an ultra prop carbon fiber, so it would seem to be impervious, but I don't know for sure, I should probably ask bob at comp aircraft, he's been really helpful.

[3cells]

more progress, getting the cage formed

[3cells]

fake prop, for checking clearances

[3cells]

3/4" expanded foam PVC for the seats, seat backs, and standing deck, I'm tired of wood and steel decomposing in salt water!

[3cells]

so... it's been a while, yes I'm slow, and life gets ridiculously busy! but, I finally have this beast working, and working well! I've almost dumped it twice, in the process of learning the difference between an airboat, and a fanboat. But it's a nice problem to have! A huge thanks to all you folks that have been not only helpful, but downright encouraging, especially Yamahauler for the tip on using the big generac v twin direct drive. Now, on to some pictures!

First is the side view, on the trailer, I finally got the seats covered. And the critical (extremely!) rudder pivot and placement figured out, (the pivot was too close to center at first and on my first experimental run it went full lock to the right at full throttle. At that moment I was;
A: really glad the water was glass smooth as I went pogo sticking sideways up the Suwanee, (the locals were probably amused)
B: really glad I kept the center of gravity as low as possible.
C: really glad to have a nice wide hull
D: firmly convinced some guardian angel types did me a solid!

2nd picture's the front view, showing off the nice inexpensive, but really bright LED headlight for night running, and the bracket I made to avoid the inevitable foot to light connection, (where the light loses). I'm really glad I added non skid to the gel coat on the front deck, and the drainage holes and curvature have already proven well worth the hassle. Original front deck was flat, no scuppers.

3rd Picture, looking at my slightly lumpy, but functional rudders and cage assembly. The fan cage and rudders are a modular unit, 6 mount points for stability, Undo 6 bolts, disconnect the steering cable, and the whole assembly lifts off. I'll probably re make the rudders in the future, I've gotten better at TIG. I'm using a single Morse cable control for steering, It gives you 3" of usable travel & it's working fine. I intend to add a second cable in the near future in a pushme/pullyou configuration, for just a little more security, and it will probably let me lose some slack in the steering.

The recommendation at comp aircraft was a 48" 3 blade original ultra-prop, Yamahauler was running a 50 or 52" prop at 12 degrees, on the same motor, before some tuning mods and was pretty happy with the results, so I figured why not experiment a little. I ordered a 54" 3 blade with 10 degree pitch blocks to start. you can always shorten the blades, and pitch is easy to change. 3600 is the max rating on this motor,and as she sits now it tops out at about 2850. I really am OK with the performance right now, I presently have more boat than pilot so I'm waiting till I'm more comfy with controlling this beast before undertaking any engine mods. It takes a while to get up on plane, but once you're there, you can back off and cruise at about 3/4 throttle, in deep water, no headwind, minimal waves. Me and the wife and gear are probably around 300 ponds payload, and if I have trouble getting up on plane moving some weight up to the standing deck helps.
You can see the double, high output bilge pump outlets. I installed these after my first introduction to the famous following wave, we didn't sink, but it took me 20 minutes to bail out all the water!

4th picture,
closer view, other side. you can see the gas tank & battery placement, I might move the tank down to the floor to lower my COG, but I need to keep the battery high and dry, salt water can kill a battery in a blink, and I'm still insecure about that back wave. I put the headlight/running light/mast light switches, and all connections in a nice watertight latching junction box (clear top) I found on Amazon. Ran all the wiring inside PEX. One of my remaining fixes is to get some 1-1/4" stainless flex for the exhaust, without having to ship it from England, I haven't had much luck finding any, seems like most exhaust flex in SS starts at 2" and bigger, for cars. The mufflers could be quieter, but after 1/2 throttle the prop noise kinda makes it irrelevant.
I wish there was a mini-airboat hands on training academy locally, would save me lots of grief! Biggest complaint I have right now is controlling this thing at slow speeds, and docking. A nice gradual throttle down keeps water out of the back, but this thing is so short at 12 Ft. as soon as the power is off, it just swaps ends, awkward!! Folks on the dock probably don't want to see a horizontal Cuisinart approaching, so I shut down a nice distance from the dock, jump up on the front deck with a paddle, and paddle the last few feet in, it's easier to control the spin from the front.




Other than that, I'm a happy camper! You have no idea how gratifying it is to realize you just skimmed across a mud flat with 6" of receding tide, (at night) that would have glued your previous boat in place for at least 3 hours till tide change!
Cheers!
Questions, comments or suggestions are welcome! As soon as finances permit, I want to build an aluminum hull about 2' longer, same motor and rigging, might help with the carousel effect. At that point I'll have to move to a different part of the forum!

[Corky]

That's a good looking rig there..... I'm glad you're out there having fun with it...If the water coming over the transom is your main concern you could possibly add a splash tray back there to keep the majority of it from climbing the back...Nothing fancy since your future plans are to build a new hull... But again, great job on the build I'd be proud too !!!

[3cells]

Thanks Corky!
My previous rig was very stable in the water, and heavy, and gave me a top speed of 6 MPH. By comparison, my Navionics app recorded my late night/low tide / mud run 2 nights ago at 24 MPH. Most folks wouldn't think much of that, but for me, a 300% increase in top end is really taking some adjustment! Blink or twitch and it feels like you could end up in the next county, or worse, especially at night! The guys with the big-dog v8 rigs that top out at 50 or 60+ are totally incomprehensible to me!
Thanks again for the encouragement, and the priceless advice from experience!
This picture is from my first experimental run on the Suwanee river, a couple months back, hadn't finished everything, just wanted to test the float/balance & steering.