If the 1/2 round, thick skinned, automotive foam, that is pictured on my boat, yes. It is UV resistant, what is on my pusher is 14+ years old, and still in good condition. It is not real easy for the average guy to find, so I set Harbor Models up with a source, that the shop I managed had, just go to them. They have 3/8'' and 1/2'' wide, take your pick. Attaching, wipe it down with laquar thinner,lightly scuff up the hull paint, and wipe down. The best glue currently, is a FRESH bottle, of r/c car tire glue. Ck. for any non-glued areas, and if needed, use thin CA, on a toothpick. You want them to hold, when you and that concrete wall, come together! CaptCB

My bits arrived from Harbor Models today and I have two silly questions:

1. Since the prop is R handed, is seems like the shaft will just unthread itself when I hit the throttle. Do y'all solder your props on? (Shaft came with a collar/grub screw and small nut. I assume the collar goes inside the hull, to keep the shaft for leaving the tube. Likewise, I assume the nut backs up tight against the prop for some reason. Is this supposed to keep it from unscrewing? Can't imagine that working.)
2. I need to shorten the stern/stuffing tube and shaft quite a bit. There are bushings at each end of the outer brass rod, which presumably is what keeps the grease in. Can one simply unsolder these, cut the casing to length, then resolder? Sound so simple, I assume I'm missing something obvious. I'm also planning to make a second tube from scratch, so advice will help me with that little project.

Thanks for whatever light y'all can shed. Needless to say, I have a TON to learn about the boat world.



Matt

Matt,
which stuffing tube/shaft did you buy? They are not all made the same. If it has a bronze (oil light fitting) at either end..they are pressed in .DON'T try to wiggle them out with pliers...they will break. I cut my tube to length (remove the shaft first),

Throw the nut in the trash, and use RED locktite! I would use a Dumas U-joint system, and not use the collar, either. You should use Nylon, or Delrin, thrust washers at both ends of the stuffing box. Are you using a 4mm shaft? What is the O.D. of your stuffing box? Finding Nylon washers that match both the ID, and OD, is not often easy. I some times have to make my own. Nice advantage, being a skilled machinist. Let me know the dimensions, I might have a couple laying around. CaptCB

BOZ and CaptCB, I bought the Robbe no 1444. Here's specs I found on the web:

Robbe 1444

Shaft diameter: 4 mm
Stern tube diameter: 6 mm : 232
Shaft length: 300 mm
Thread: M 4
Bearing: Plain bearing

The way I read that, I have 1 mm around my shaft for grease.

If the bushings are bronze, how does one remove/replace them after cutting to length?

How are thrust washers held in place? Should I ditch the bronze and just use thrust washers?

I also have the red coupler at the top of this page http://harbormodels.com/site08/main_...propulsion.htm. Does the brass bit on the end of the shaft (that goes in to the u-joint) keep the shaft from slipping out of the stuffing tube? Thus no need for the little collar/grub screw arrangement? Do you all file a flat spot on the shaft to keep the grub screw from slipping around the shaft? (Model airplane shafts often have a flat spot/notch for this purpose, but the forces at work are, I believe, substantially greater.) In any case, I assume something must rest and spin against the end of the stuffing tube to keep the shaft for backing out and slipping into Davy Jone's Locker.

I realize I'm asking lots of questions, and some are pretty basic, so I REALLY appreciate y'all patience. I'm reminded of when I first started flying RC, trying to figure out how to calculate power systems, watts/pound, etc.. Now I do it in my sleep.

Thanks again!

Matt

On the piece that you cut off, you need to find a drill or drift that fits the inside of the tube exactly for the next step. The cut off part should be no more that two inches long to make this step a little easier. Spray wd 40 or equivalent on the inside of the tube. Mount the tube vertically in a vise (hobby vise is better because it has a diamond opening on top to hold the tubing better) making sure you are not clamping the bearing.Place the drill bit with the tip up (be careful here) Lightly tap the drill bit (with a dead blow or wooden hammer) making sure the tube is secure in the vice increasing power until the bearing is free or the tube needs to be tightened more in the vice (it is a process I go through every time) It may require using a slightly smaller drill if you can't get enough pressure to hold the tube (compressing the tube can lock the drill bit so it won't move)
If you make a flat spot for the grub screws, clean any burrs so as to not gaul the bearing when putting it back in the stuffing tube The brass collar is a fail safe if the coupler should fail. Thrust washers are not needed on a solid shaft.
When reinstalling the tube bearing, slide the shaft back into the tube sliding the bearing over the shaft and back into the tube end. This will help keep the bearing going in straight into the tube.
brain dump
jim

Originally Posted by BOZINATOR

On the piece that you cut off, you need to find a drill or drift that fits the inside of the tube exactly for the next step. The cut off part should be no more that two inches long to make this step a little easier. Spray wd 40 or equivalent on the inside of the tube. Mount the tube vertically in a vise (hobby vise is better because it has a diamond opening on top to hold the tubing better) making sure you are not clamping the bearing.Place the drill bit with the tip up (be careful here) Lightly tap the drill bit (with a dead blow or wooden hammer) making sure the tube is secure in the vice increasing power until the bearing is free or the tube needs to be tightened more in the vice (it is a process I go through every time) It may require using a slightly smaller drill if you can't get enough pressure to hold the tube (compressing the tube can lock the drill bit so it won't move)
If you make a flat spot for the grub screws, clean any burrs so as to not gaul the bearing when putting it back in the stuffing tube The brass collar is a fail safe if the coupler should fail. Thrust washers are not needed on a solid shaft.
When reinstalling the tube bearing, slide the shaft back into the tube sliding the bearing over the shaft and back into the tube end. This will help keep the bearing going in straight into the tube.
brain dump
jim

That actually made sense!

I'll TLDR recap it and you can tell me if I've misunderstood.

"Carefully bang the bushing out from inside, then reinstall with the shaft in place to keep from deforming the bushing."

That sound right?

Follow-on question. Can anyone explain what keeps the brass u-joint insert on the prop shaft side from just backing out of the plastic u-joint sleeve? Does friction alone hold it in place?

Matt

I will try to post a photo of one of my boats drive systems. CB

Here is a photo of my 1/32 LCM-6 based tug. I use a similar set up in most of my boats. CB

Originally Posted by CaptCB

Here is a photo of my 1/32 LCM-6 based tug. I use a similar set up in most of my boats. CB

Super helpful photo. To my eye, the grub screw in the brass bit on the shaft side of the coupler is all that's keeping the shaft from pulling free when you go into reverse? And that same coupler piece rides up against the stuffing tube? Is that a friction point?

You must be getting so sick of my questions. I'm just about finished swapping out all the ESC and motor connectors. Will post a photo in a bit.

EDIT: Photo attached. Swapped the power leads to Anderson Power Poles and the ESC/Motor to gold bullet connectors. Do marine folks bother with this sort of thing, or is there perhaps some other standard used in wet environments?

ESC programming was as snap and I now have forward and reverse control. I'll need to remember to swap the leads for breaking in the motor so I don't set the brushes backwards.

Yes! this boat does not have ANY thrust washers, and, over the years the bushings have worn. This model has hundreds of hours of use, and I wish I had, put in Delrin, or Nylon, thrust washers, as the way the boat was built for super scale detail, I cannot remove the props, or shafts. They now rattle some. Every boat built since this one, has thrust washers, at both ends of the stuffing box! CB

HINT: always use thrust washers.
Two like matrials will wear faster. Brass on brass and so on.
I always use nylon, delrin or stainless steel.
Always put a flat were the grab screw sits. If not it will rase a burr and destroy your bushings when you remove the shaft.
I do mount the coupling against the stern tube. In 60 years I have not had one come lose.
For under 5 amps I use the Tamya style connectors, Over 5 I go with Power Pole (Sermos) or 4mm bullet.

I will get some photo's of my barges, showing the hulls, and the skegs. The weather has been beach overcast, not real good for photo's. My thoughts on dimensions are:24''L x 8"W, or 30"L x 10"W. I have one that is 39x10, with skegs. Push's good, and tows GREAT! I am not against, possibly doing one in fiberglass, but to mold in the skegs, is WAY to costly. What do you guys think? CaptCB

Originally Posted by CaptCB

I I am not against, possibly doing one in fiberglass, but to mold in the skegs, is WAY to costly. What do you guys think? CaptCB

I agree on the skegs and molding. That is something that can be added pretty easily if one has a little building experience, But a basic hull for barges is needed. Made one for a manufacturer thta is awaiting molding process.

Hello all,

As promised I am posting a few pictures about my build.
Just a few pictures as the build goes on not a whole blog.
Propulsion: Graupner Speed 500e 3:1 gearbox. 35mm 3blade prop. Viper Marine 15A speedcontroller.

My 5 year old son likes all the other springer pictures so I am afraid I have to build a 2nd one as soon as this one is finished
So an extra tx is needed.

no1 speaks for itself
no2 I clamped a square in to keep it all .....ok square
no3 The cutoff becomes the stand inside the transportcase to protect the ship.

More to come leighter

John.