54" Bonzi Fountain build

[blackcat26]

Chris what size props did you end up with? Dia and pitch

[Rumdog]

Arent they lower than sufrace drive stingers already? You may just need bigger props..

[Make-a-Wake]

Hmmmmm, looks like they are setup as surface piercing drives.........can you fit 448's on there?

[ScarabChris]

I started off with some ABC props from OSE. They are 3 blade 45mm (abc-1816-10-50(3) which are the biggest diameter props that will fit. I might be able to squeeze 47mm props.

I also have some props coming from prop shop UK, they will be similar though.

IBut I am positive I put the drives too high, I had the hull bottom even with the propshaft. I only did this because Graupner describes this drive as such....

Suitable for medium-sized to large motor boats and motor-yachts. Designed expressly for surface-piercing propellers

If a fully submerged propeller is used, a smaller diameter must be employed.

I took that as a surface drive so I mounted it very high. Now I am reworking the transom and motor mounts so the cav plate is just slightly above the hull bottom by about 5 mm.

[ScarabChris]

Hmmmmm, looks like they are setup as surface piercing drives.........can you fit 448's on there?

You beat me to it! Your depiction is 100% accurate. By tomorrow I will be able to give it another test run with the drives at the "correct" hight.

[Rumdog]

Those props are TINY for those motors, and for that hull.

[blackcat26]

Not to gang up on you Chris but I think Rum is right. A lower pitch prop in a little bigger dia might help a little. 457's would be closer to par.......

[ScarabChris]

I don't feel ganged up on, no worries.

This is a hobby and I am building this boat on spec. There are no previous builds identical to this and no "right or wrong" way to do it.

This is trial and error and I'll have to keep tinkering until I dial it in.

On the props, I am not very familiar with the numbers such as "457" and "448". All I can tell you for certain is nothing bigger than 47mm in diameter will fit and its a 3/16 shaft.

[blackcat26]

Ok the 457 is an Octura x457. They come in counter-rotating and the 448 is also Octura, x448 not sold in counter-rotating. I agree about the testing til you get it right and it's easy for us to sit back and tell what's wrong after the fact. If we seem too critical at times we are only trying to help. Keep up the good builds my friend!

[ScarabChris]

OK the x457 looks to be a 57mm prop. Won't fit.

Lets see how it does with the drives lowered and I'll go from there.

And if I still need more prop, prop shop UK has 4 and 5 blade props that will fit.

[LarrysDrifter]

Sorry to hear about the drives.Hopefully,you can get the right sized props for it given what will fit.An x448 is a 48mm prop with 1.4 pitch as with all x series props.

[ScarabChris]

Nothing really wrong with the drives. I believe the main problem was the hight. I already took care of that. Props might be an issue but I don't think any prop would work with how I had the drives set.

If I stab the throttle the boat literally jumps out of the water. This tells me the props are biting and utilizing the power the motors are pushing. But as soon as the boat gets up they suck in air. The props just needed to be deeper.

I know a LOT about dialing a real boat with drive hight and props. I should have known better than to put those drives so high.

I should be able to get a quick test in by noon tomorrow. If I can get the boat on plane without massive cavitation then I can dial in the right props later.

[ScarabChris]

OK.......lowered the drives. It got on plane and was just gaining speed when that sound occurred! Stripped the gears in one drive!!

It was the input shaft gear and I did remove the shaft to put the U-joint so it could very well have been my negligence by not making sure the gears had a tight mesh.

So.....where does that leave me? Yeah I'm going back to the surface drives for this boat.

Its not just the gears. I think these motors are way to strong for them for starters and the drives are just not big enough for this hull and they don't allow for a big enough prop.

Even if I got the drives set right and they held up I think finding props to push this big heavy boat would have been an issue.

I will search out some gears or maybe I'll even buy another drive and use them on the 50" Apache with motors that are suitable for these drives. That hull is smaller and much lighter and I think that will be the scale build.

But for this Fountain.....back to the MHZ surface drives.

Oh well.......

[ScarabChris]

Got a lot done today, I would be ready to run it by Christmas Eve with the MTC surface drives but now I have no props. The props I originally got from Prop Shop UK for these drives are very nice, but they are for a 3/16 shaft. These drives are 1/4" shaft. So now I'm on the hunt for props once again.

LOL......this transom has had more holes filled than a Las Vegas brothel. I think I'll name this boat swiss cheese....LOL



But I'm not bad at small scale fiberglass repairs....


I had to cut the motor mounts out for the z-drive set up and build new mounts out of 3 MM carbon fiber. I thought the inside was going to look like crap but it doesn't look bad considering all this hull has gone through.


I ordered a dual rudder from Top Secret boats that should be here tomorrow. I think it will look and handle good with these drives. I think the original MHZ rudder was just to small, it didn't look right.

More to come soon.........

[Doby]

Zzzzzzzzzzzzzzzzz..........ZZZZZZZZZZZZzzzzzzzzzzz zzzzzzzzzzz..............

This build is taking to long.....................

Things are frozen up here and I need to boat vicariously through others.......

ZZZZZZZZZzzzzzzzzzzzzzzzzz....ZZZZZZzzzzzzzz...... ................