Advice for buildin aluminium hull.

[M0RYAK]

There are two beams that are welded to the stringers. For lowering of rear part the engine I will removing welding and move ahead each beam about 4 ". Additionally it give me possibilities use hull jack (if I will not welded center stringers). How many stringers should be free?
Distance between stringers 7".

 

[M0RYAK]

Off course for first I will try to tune the engine engle.

 

[Slidin Gator]

Moryak,

All I can say is "Holey Crap", you built a stout hull, way more runners (fore/aft T bar) than normal, but she should take a beating. What is the hull thickness?

The major flaw you made is the bracing that your Engine stand is mounted too. I call them bulkheads. You should not have welded the Port/Stbd beams to your runners. If you had bolted connections you could tune your hull.

When you did all that welding, the bottom of the bulkhead beam sucked up, causing the hull to "dome up", making it higher in the center than the edges, giving you the porpoising issue. You want a very little bit of outward balloon on the hull. Too much balloon and she runs on the nose (bow) it does not take much.

I think you need to figure out how to shape what you have, it's gonna take some force and heat. Aluminum is tricky if you are not experienced.

 

[M0RYAK]

The hull thickness is 2mm. It is reason why I instalsted beams. I wanted have stout hull.

Before any action I would check the bottom with a straight edge or string line.

If I correctly understood your advice use the two t-bars (runners) port and stbd for bolt connection with beams (bulkheads).

I was read many posts at this sait about hop.... I founding information about shifting of engine's stand ahead to 2" give good effect.

I have rear part of stand 7" from transom.

 

[Slidin Gator]

Center of hull in stern perhaps 2-4 mm (1/16-1/8”) bubbled out/down vs port/stbd rails is the goal for shape. How you get there is up to you.

 

[M0RYAK]

Center of hull in stern perhaps 2-4 mm (1/16-1/8”) bubbled out/down vs port/stbd rails is the goal for shape. How you get there is up to you.

Good! Noted.

If possible provide inforrmation about distance from transome to rear part of stand on your airboat.

Thanks!

P.S. 2 mm is so small that I could lose attention during construction.

 

[M0RYAK]

I checked the bottom geometry from inside. There is a "dome up" (about 4-5mm) between bulkheads and before 1st bulkhead.

 

[M0RYAK]

My friends ended the season of duck hunting, week ago.They were very lucky.

 

[M0RYAK]

During the short vacation I had some walking.

[youtube-video]https://youtu.be/6C5ykHTC6dQ[/youtube-video]

[youtube-video]https://youtu.be/JpEb-RFMu_o[/youtube-video]

 

[M0RYAK]

I made two hull jacks and cut the first bulkhead, but didn't solve the porpoising problem. Perhaps they incorrectly placed. Need to reinstall the first behind the fuel tank or make third. Unfortunately very restricted with time.

 

[M0RYAK]

Over the past month, I have made several updates to my airboat.

 

[M0RYAK]

I mounted the battery switch.

 

[M0RYAK]

I painted the hull and rigging.

 

[M0RYAK]

New place for the fuel tank for shifting one from bottom to engine stand.

 

[M0RYAK]

The rudder system was improvements.

 

[M0RYAK]

The grass rake and the passangers seat for summer.

 

[SWAMPHUNTER45]

Looks good !

Your weather should be getting very nice now are you planning to go to different regions with the boat this summer?

 

[M0RYAK]

Looks good !

Your weather should be getting very nice now are you planning to go to different regions with the boat this summer?

Thanks!

In this year the weather is strange (windy, rainy during all may), But summer will very hot usually temperature is about 40 degree celsius.

I made this airbot for my present region Astrakhan aria, Delta of river Volga, but it's big water locations I will discover it long time, an airboat gives big possibilities for it. I am at my work and will come back to home after two months.

 

[SWAMPHUNTER45]

Look forward to seeing video from your part of the world.

Stay safe

 

[M0RYAK]

I have a good news. I found the reason of hopping, the bottom had rising from the aft bulkhead to the transom about 5 mm. I installed the wedge between poly and the transom 4mm for all transom width and plus 4 mm at middle part (total 8 mm wedge at middle). The result was fantastic. The airboat no hopping, the speed is about 40 mph. I reverted the engine angle to first position, the airboat runs still good.

I workd with my airboat all month like a crazy, I had many trial runs, I used difference wedge, etc. but now I very happy.


I created some videos for check running up. Any remarks is welcome.

[youtube-video]https://youtu.be/Y01PDPMKkdI[/youtube-video]

[youtube-video]https://youtu.be/4NSZQ4pFDnw[/youtube-video]