Vintage Gentleman’s Cruiser

[Bob Abell 2Participant @bobabell2]

Hello Paul

The vibration is not much of a problem really

I'm assembled one pair of motors now with the locked up grub screws and will have a test run tonight or tomorrow morning……..Fresh air and water running and make some comparisons

Having thought about the belt tensioners, the more I think it is a nice feature to fiddle with

Take a look at the video we took last April, to refresh your memory banks

Bob

[Paul TParticipant @pault84577]

Bob

How about mounting the motors themselves on rubber anti-vibration mounts, these will absorb any odd vibrations and might allow your motor pairings to run more smoothly.

Paul

[shipwrightParticipant @shipwright]

Hello Bob,

I did hint at possibility of problems with mechanical oscillations in my posting dated 29th Nov 2014. Having thought about this again I note that the MFA 850 is a 3 pole motor and there might be a significant fluctuation in torque as the rotor moves through a full 360 degree turn (ie one rotation). In a typical 4 cylinder car engine the rotational fluctuation in torque is smoothed out via the inertia (energy storage) of the flywheel. I guess that you wouldn't want additional weight in your boat and anyway there probably isn't sufficient space to instal 2 flywheels. One thing that might be worth doing is to align the 2 rotors that are coupled via the toothed belt so that the torque fluctuations are synchronised (ie both motors reach peak torque together). By "align" I mean that the 3 pole axes are aligned :

Motor 1 Motor 2

Just an idea – might not help !!

Ian

[Bob Abell 2Participant @bobabell2]

Had a lot of mail tonight

There's nothing like a bit of controversy to get the thread animated!

Firstly, Ian

You are correct about the 850 motors, they are very lumpy to rotate

I like the idea of a flywheel, as it would enhance the motor appearance……Got plenty of room too

Don't fancy messing with angular tuning though

Haven't found your earlier post yet, but I will do

Paul

The adjustable belt tension idea sounds attractive and it would be nice to hear how the revs perform with various belt tension settings

The more I think of the belt mismatch, the more important it seems

At the moment, one belt will be about 20 thou in front of the other, but adjustable belt tension, should balance them out somewhat?

All good fun, chaps

Bob

[Bob Abell 2Participant @bobabell2]

Hello Ian the Shipwright

Found your post…….It was on the 28th…btw

Your concern really was the length of the propshaft and possible whirling

I reduced the propshaft later, to about 15"

Bob

[ashley needhamParticipant @ashleyneedham69188]

Getting toooo complicated. Firstly, have the motor shafts and any other shafts got flats on for the grub screws to bear on ?? if not, there should be. If for norhing else it gets more grub screw thead in the boss.

Rubber band/toothed drives should be very smooth and will take up any very small discrepancies easily.

Vibration could simply be coming from the out of balance pully wheels.

If the boat does not shake uncontrollably when running the motors, then all must be ok. Bound to get a small amount of vibration with that many motors, all of them slightly out of balance in themselves.

Loctite, get some, stick the grubs in, end of problem

15 inch propshaft unsupported in the middle more likely your vibration issue.

Ashley

[Bob Abell 2Participant @bobabell2]

Thank You,Ashley

All the shafts have drive flats…………The flats are 4mm wide, this allows for a grub screw protuberance of 0.7mm

Test run motors 1 and 2 this morning with the new locknutted grub screws for 15 mins and all is well

Not a sign of coming loose

Watched the pulley's behaviour close up and I'm impressed

I was even more impressed with another dinky little idea……..I pressed a free running flat wheel on top of each belt……To vary the belt tension!………Clever Bob eh?……..But there was no change in mechanical noise

Would you believe it?……I've run out of M4 nuts!

Stopping all engines and off to Wilkies in Ashton

Back soon……..For more rotational fun

Bob

[Mark Jarvis 2Participant @markjarvis2]

HI Bob

My huntsman has a long propshaft, i cured the vibration and noise by putting two PTFE bearings down the prop tube, about 1/3 and 2/3 the length, absolute swine to refit the propshaft but well worth the effort.

Previouse post mentioned allining the motor poles, what if you miss allinened the poles, ie, 120 degrees appart? this might allow for the different tourque from each motor to ballance itself

Mark

[Bob Abell 2Participant @bobabell2]

Thank you, Mark

I could experiment with the timings, simply by rotating the pulley's

Will give it some thought……Afterall, it's not been tried before

Bob

[Bob Abell 2Participant @bobabell2]

Just another test session in Coniston Pool

It`s really nice having your own lake, close at hand………Especially in the sunshine

With instant sailing display for visitors

Bob

[Paul TParticipant @pault84577]

Bob

You didn't need to go to such detail in re-creating Etherow lake, I refer to the water as most of us would just have used a hose pipe.

Paul

[Bob Abell 2Participant @bobabell2]

Hello Paul

Just amusing myself with the novelty of having the facility

Lady Joyce should be most impressive, next time out……Now that all the pulley`s will be in action

Regards to the missus

Bob

[Bob Abell 2Participant @bobabell2]

I fancy making a few Fenders, to protect the hull from scuffing……….Using string etc

I need about eight of them and they are a bit expensive to buy!

Any ideas, chaps?

Bob

[Paul TParticipant @pault84577]

Captain Bob

Try making your own by wrapping string around a foam core.

The Blue Peter team

[Bob Abell 2Participant @bobabell2]

Come, come now, Noaksy

"Wrapping string round a core etc"………..It needs the authentic knitting method for the Lady Joyce!

Bob

[Paul TParticipant @pault84577]

Then you will have to learn crochet

[ChrisBParticipant @chrisb29081]

Found this on t'internet. Hope it helps.

http://the-iron-dutchess.com/ropefenders/

Chris

[Bob Abell 2Participant @bobabell2]

Many thanks, Chris

I've had a quick look and they don't look that difficult to create

Also, many thanks to Mike Farrell for his kind offer to make me some

I've said to Mike that I prefer to have ago myself, at the moment, just for the challenge

Bob

[Bob Abell 2Participant @bobabell2]

Not making much progress with the Fender construction, chaps

I blame my tools and lack of the correct string!

Had a novel idea though……In keeping with my wacky VGC build

Remember our childhood days?…..We used to plait miles of woolly tubes….Not you, Dave, using a cotton reel and four nails knocked in one end?

I wonder if it is feasible, making a large special reel with many nails, to create the required woven effect?

Worth a try and is just up my street!

Bob

[ChrisBParticipant @chrisb29081]

Like the lateral thinking Bob. It's called French knitting. Or the "trade name" is knitting Nancy.

Plenty of links and "show you how" on the net.- certainly got me thinking……

 

Chris

Edited By ChrisB on 31/07/2015 09:09:49

[Bob Abell 2Participant @bobabell2]

Hello Chris

There's plenty of links to French Knitting, right enough, but surprised there's no examples with more than four nails?

Looking forward to the experiment and results

Bob

[ChrisBParticipant @chrisb29081]

Hi Bob,

Just a few thoughts…

From memory, the French knitting gives a loose woven tube with the four nail set up. Using more nails should in theory do the same but with a tighter weave I think.

I would think that if you make the nail configuration non regular, ie 5 nails , you might introduce a spiral into the weave pattern which could look pretty!

Also, have you given any thought to a "frame" to go inside the tube to give consistent diameter; wood dowel, plastic tube, or perhaps sponge? You might be able to stretch the tube over a suitably shaped former to produce a bow fender too?

Now I might have an old wooden cotton reel in my odds bin…….might have to give it a go too.

Chris

[Bob Abell 2Participant @bobabell2]

Hello Chris

I can think of plenty of variations now……Even two tone?

I'm using a wood block with a 1" dia hole, for the first attempt

Bob

[Bob Abell 2Participant @bobabell2]

Just been informed via a PM that a rival mag has just published an article on fender making…..Using the French Knitting principle

What an amazing coincidence?

Will have to call at Smiths for a crafty look see!

Bob

[Bob Abell 2Participant @bobabell2]

This is my first attempt at the Fender Weaver, but at the moment, things haven`t worked out too well

I can see now that the stitches need to be more orderly and accessible somehow

An interesting project, none the less

Bob

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