|M Harvey||08/05/2021 08:08:03|
|21 forum posts|
So I've managed to strip down my metal hulled beast...
I have also attached a universal joint to the drive shaft and on closer inspection the shaft is dry.
I have cleaned it and am wondering what oil / grease to use on it?
All advice gratefully received.
|ashley needham||08/05/2021 08:22:51|
7121 forum posts
Michael. That’s so cool! What a fantastic hull. I would spray it with red-oxide, then spray the top black..add a boot topping line and leave it at that. The thinnes of the spray should let you see all that detail but provide adequate protection bearing in mind how much time the hull will be actually in the water.
Propshaft lube. This something we cannot agree on as to what’s best.
Oil filled, smear of grease, drop of oil now and then on bearings, oil inner bearing and let water lube the bottom one....there is no right answer. Some swear by this or that....
your choice really, but just DO NOT pump the shaft full of grease! As this causes massive drag on the shaft and strains the motor.
|Dave Cooper 6||08/05/2021 10:03:40|
|285 forum posts|
Inner shaft with outer tube :I use a smear of Vaseline (petroleum jelly) at both ends of the shaft. Lightly pack nylon bobbins /inner shaft just at the extremities. No problems with leaks or shaft drag so far. Clean and replace every 1 to 2 years dependant on use.
For a larger hull, I would use either 'SIF' bronze bearings (no lubrication needed), or, Oilite bushings with just a few drops of light machine oil (eg "3-in-1" every so often.
Do you have exposed shafts running in plain bushings or, something more sophisticated ?
Is the motor end of the shaft(s) above or below the waterline ?
Edited By Dave Cooper 6 on 08/05/2021 10:11:17
|Richard Simpson||09/05/2021 09:46:29|
308 forum posts
As Ashley says, no straight answer but everyone does agree that a stern tube full of grease will invariably overload, if not stall, the motor. I was once advised by a supplier to use grease in a 8cm long 4mm stern tube with a 10cm long 2mm shaft. It wouldn't even turn!
Sealing the ends with a spot of vaseline or some form of waterproof grease on the thrust face and maintain minimum clearance is a good idea and filling the tube with a light oil to prevent corrosion is usually a good way to go. If not already fitted adding an oiling tube to the top of the stern tube is also worth thinking about.
|M Harvey||09/05/2021 19:49:59|
|21 forum posts|
It seems I have a 4mm rod inside a casing which is well and truly fixed into the hull. The rod is approx 140mm.
I'll go with a little bit of vaseline and some oil between.
As to the waterline, I and trying to find out how you calculate the waterline? The motor is definitely below the waterline, but I'm trying to work out where to draw the line for the red paint to go on the hull...???
Any help gratefully accepted.
|Dave Cooper 6||09/05/2021 22:03:57|
|285 forum posts|
I think you can go with the lube ideas previously mentioned. Depending on access, a lubrication tube would be worth considering as Richard suggests. I think "Model Boat Bits" do a kit which you may be able to 'retro-fit'.
As for determining the waterline, I think I would start by weighing everything you are planning to put inside the hull - motors, batteries, radio etc.- the lot. Then, plug up all the leaks (Blue-Tack /whatever's to hand) and find some water -.kiddies paddling pool, garden pond, friend with a pool (you should be so lucky !).
Initially, I would float it empty, being a steel (?) hull it should sink to a 'natural' level but may be a bit 'wobbly'. Note the waterline and the boat's trim - eg bow low /stern low and any side-to-side list.
Now add ballast equivalent to the weight of the planned internal equipment. Move it around until a satisfactory trim is found.
You may find the level is higher than you thought acceptable. Come back to us with some photos. I'm sure the experts will be able to say what's safe. Then you can draught out your lines...
Cheers for now,
Edited By Dave Cooper 6 on 09/05/2021 22:11:20
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