Great to hear you got it running well. All that hard work paid off! Looks great.

thanks,
it's been a bit of a sruggle but you guys have been very helpful and supportive

Did a run today that was cut short by radio issues … turns out I’m a Hitech Electron 6 victim. If it’s too hot outside these rx’s just freak out.

Hasn’t been an issue before with my gliders, but I guess the interior of a boat on a summer day in Barbados is a bit much for them.

Just wanted to ask a quick question:

Do single motor boats this size ever drive straight?

I’ve been able to compensate for the torque roll a bit by moving my batts around. With my current setup the boat lists severely to the left at rest and low throttle settings. As a result in these conditions it wants to go left all the time. So I trim right.

However at 3/4 throttle and above I’ve noticed that I still have to drive the boat out of the torque roll .. a chunk of left rudder at full throttle is needed to keep her upright and on track.

Like you guys know I’m new to boats, is this normal?

The test of a well trimmed sloper, is just releasing the sticks and watching her go straight and true. You put an engine in the mix and things get a bit tricky.

So do you drive your boats thru the throttle band .. or have I built a wonky boat?

Without countermeasures, a single prop boat will always suffer from propwalk, depending on the type, propsize, set-up, etc and will not run straight.

When the propshaft is positioned off center, or a few degrees off center, most propwalk issues are gone, once the boat is on the plane, with a little rudder input sometimes.

Your boat most certainly isn't wonky, it's simply a small boat which has too much power installed.
There are limits to each design, your's appears to be riding on the edge (and beyond)...

Regards, Jan.

Thanks for the input Jan,

I must admit I was on the verge of shelving this boat, ordering a new motor and ECS and starting construction of a twin-engine cat or mono … might still do that.

But I’m quite interested in this thrust offset you mentioned … I figure I’ve come this far so I’d really like to get this boat to the point that I can comfortably hand the controls to the wife, daughter or some of the children who come down to the pond and beg to drive the boat.

How much offset are we talking about? I assume looking from the back of the boat,
I want to move the drive shaft over to the right … correct?

It’s a pity the drive will have to be pulled out again.

Here’s an idea I’ve been thinking about. Right now the 1/8” prop shaft is 2.25” long and the stuffing tube extends 1.5” from the transom. Effectively the drive shaft passes thru the transom about 1/8” or so. I built it this way so I’d have a good bearing surface for the drive (keep it nice and true) and also to minimize the chance of having water come up the stuffing tube.

Do you think I could shorten the drive shaft to say 1.5” that way I’d be able to bend the stuffing tube at the transom to experiment with offset and drive angle. Mind you, I’d only have 3/4” of drive shaft supported by the stuffing tube and the wire might bind if I bend too far.

I’d really appreciate some input … recommended offset angle and a bendable wire drive stuffing tube?

PS: right now all 8 cells are on left side of the boat and she still wants to roll right.

Jan, it being a V hull would you offset the driveshaft, or angle it to the side a bit? I thought that the driveshaft should exit the hull about 1/8'' up from the keel. Is there a better way to do it?

I’m looking forward to Jan’s comments as well …

My drive is centered 1/4” above the keel … the exit hole in the transom would have allowed an 1/8” height but it was 2:00 a.m. on Sat. morning and I was having a hard time getting the tube nice and low but still at 0 degrees … I got lazy and said good enough.

Anyway the speed and stability increase with the 0 degree shaft are amazing …. All I can say about the video I posted is … it was only half throttle!

I don't know if my words will be worth a plug cent but here goes. Ok, reduce the motor size by 1/3 , next make stuffing tube extend to 2 1/2" by soldering a sleeve and inserting one size bigger to slide over the exiting stuffing tube and the extention to make 2 1/2" and solder. Slant stuffing tube and including motor at a angle toward toward the right 1/4" from motor to prop by using at ruler and felt pen and draw a line and keep the strut area parallel with the keel. Now for me a balanced 632 prop that is modified in shape but 32mm kept in tact!

Thanks …

Just so I understand .. the prop should be about 1/4 off centre, if the stuffing tube is extended to 2.5” from transom? Or @ 6 degrees … I didn’t use my trig … just did a quick drawing.

I’m hesitant to increase my shaft length though … I’ll have to build a new rudder standoff if I do that.

I'll definitely do the shaft offset ... just want a consensus on how much.

You will find some boats have the strut extended to 4" and the rudder offset to the right 1 1/2" and rudder at 1 1/2" from transom. The boat i'm referring to is Dick Crowe's El Lobo II with just about those figures. That boat was a national champion and with the rudder at that distance didn't create a vortex between the prop and rudder cause they were far enough apart. I got pictures from Dick Crowe himself which show the distance i mentioned. With all due respect, all info i type can be backed up and verified plus have all info John Finch's made in a 4 page document. Also a lot of articles can be found in RCBM mag. by John Finch on speed secrets for monos and hydros. Ok, in all honesty and all the work you have put into your mono, you could have bought a wooden El Lobo II kit for $60.00 and put that high rpm equipment in and be done with it. Yes, i know, i did the same and after 30 homemade boats, i had to make a decision to cut costs. I have a good dozen plans. Ok, one more , AZTEC models is going to carry a revised version of the Mutineer which will have a higher deadrise so the boat will have less wetted area and higher speed. I haven't heard from Allan of Aztec in a couple of weeks but kits are due up!

Retaobcr

Thanks for the input ..

I’m not trying to be difficult and I don’t doubt the validity of the information you provide.

Yeah I could go out and “buy” an established design, but that’s not what appeals to be about modeling. I like to research, design and build my own stuff … granted I might be “reinventing the wheel” but this approach makes me happy.

I use this forum to gain input from people who “know” boats; this guides me … that’s why I ask questions.

How long is the El Lobo, my boat’s only 15” long.

El lobo II is 22" long. This is my last post as Ridgewalker called me insane with a young and low mentality and ignorance. I told him something doesn't work, so i cannot use the site from that embarassing remark cause my advise would be useless! i love the boats. I lost a micro-bullet with geardrive and a neo motor on 8 cells and a esc of rc hydros when one cell vented. The cover blew 10 feet off the boat and sank. That was a $400.00 unit and could not find it again. Good luck! No replies!

Seems egos are being bruised around here lately ... I definitely don't want to add to the tension. Lets remember this is a hobby we're suppose to be having fun.

On another note, any further suggestions on offset angle and the "bendable" drive?

allaboutcustom ... you started building yours yet? I'd love to have someone to compare notes with!

I'm currently setting up a seven-cell monohull (45 cm long) with two low steps, like a batboat.
The bottom inside is essentially flat, so the propwalk issues should be similar to a nonstepped hull.

I just made the motormount and put the motor 3mm to the right (seen from the transom) of the center line.

The hole in the transom is on the centerline.

This way this boat should track straight without rudder input, once on the plane.

From motormount to transom is 18 cm, the shaft sticks out 7 cm (solid shaft).

I can't provide pics at the moment, my son 'borrowed' the camera...

Regards, Jan.

Thanks,

If the motor goes to the right then the prop points to the left.

Just so I understand … there’s a rotational force acting on the boat that drags the right side of the hull down. To alleviate this we move the rotational force to the left of the fulcrum (keel) so it has less leverage on the right side of the hull. Do I have it?

Should I go back to a neutral (4 on either side) battery configuration? All the cells are on left side right now. I ask because the boat currently heels significantly to the left and wants to go left at low speed …. If I offset the prop to the left it will further aggravate the slow speed tracking.

Crash

no i have not started as i am working on a boat i started a while ago and im also working on a micro brushed rigger w/ a 400 motor. i would be glad to see a vid of yours flying acros the water!!! as soon as i do i will dig up this post(hopefully it wont be that long) and show you my build. i have definetely learned quite a bit from you, you, build, and the people helping you.

Well I look forward to it

I only mount the motor offset to compensate for propwalk, it will not counteract torque.
Your riding attitude issues are a result of too much power, this size (beam) hull simply can't counteract the increasing torque when you open the throttle.

You can steer out the tracking at low speed due to weight distribution, but, as I understand correctly, even all cells on one side doesn't compensate the torque issue, right?

Regards, Jan.

Yep, with all the cells on the left she still wants to roll right ... just above 3/4 throttle or so.......

OK, I'm willing to admit defeat.

I've learnt a great deal so no regrets.... time for the next project .....

Question time:

1. What motor/ prop combo would be recommend for the current boat? This isn't my first choice ... I want to avoid guess work and the Feigao 380-14S 2820kv with X432 is a nice setup, tons of thrust and when water cooled it just gets warm. Indeed I think it could take a slightly larger prop. So I'd like to stick with it.

2. What's the recommended size for a single motor mono with a Feigao 380-14S 2820kv swinging a X432? Building a new boat is the cheapest option.

3. What's the recommended size of a cat or mono with twin Feigao 380-14S 2820kv or twin Ammo 28-45-2700kv (I currently have one of each and avoiding torque roll is pretty high on my list … given the current situation). My estimates suggest the twin mono will have to be a minimum of 7" wide @21"-24" long. just to accommodate the motors, batts and water jackets. However I don't want to build too small a boat again! Only problem is the expense of a new ESC and motor. The advantage is the reduction of handling issues ... this is just a sport boat after all.

I really appreciate all input! So don’t be shy …. All suggestions welcome!

I’m not done with this boat yet I really need to post some video of it when it gets going .....

are you sure you want a mono. you could try bbyracings micro scat cat. it is only 30 dollars. if you would like to create another one of your awesome homebrews then i would try in the 18"-20" range. good luck and keep us posted.

Thanks

I have looked at the bbyracings hulls .. they look like good inexpensive hulls and I can see the potential for significant mods and set up options. But I really enjoy designing and building. Drawing plans, cutting wood and seeing what comes out … that’s my thing.

18” –20” … Agreed I need a bigger boat for this setup. Jan also suggests the boat is just too small for the power plant.

If I go single motor mono again I want to build the smallest hull that can harness the power.

The obvious correction for the torque roll is more beam. But I was wondering if a longer hull might help as well. Ultimately I want a hot looking cigarette boat.


However, length might not be an have anything to do with it .. I figure it’s just as easy to capsize a 100’ long canoe as a 16’ one; just lean over the side!

So it might just be a about beam.

Prop(w/t)alk.

I saw your prop up close in the wiredrive thread and I must say it's huge, for this small boat, and it looks to have a lot of lift.
Have you tried a threebladed one, less lift and torque-issues?

Wings:

Another solution I have used on a narrow hull, is attaching 'wings' to the bottom, extending the V-shape, creating more beam, to counteract the torque, worked like a charm.

Regards, Jan.

Jan, do you have a picture of the "wings"? This sounds like it might work for something of mine.

Yeah ith's pretty big ... I'm new to boats so I based my choice on the specs of another boater who was running a 3000kv 400 size outrunner in an 18" boat with an X432.

I'd also be intrested in pics of the "wings" you mentioned.

What are your recommendations for hull size with my current set up ... I'm also willing to go twin.