Rolling rolling rolling ...

[Paul H (admin)]

Al's trailer has clever copper-stainless bearings. Take an 8in roller with 16mm  bore, insert 15mm copper pipe and then 12mm stainless rod and it spins freely:



I have prototyped a ladder of rollers for MilliBee's trailer, with Unistrut galvanised U channel 40mm x 40mm and stainless copper bearings. Here is a short video clip of a 22kg battery on a wooden sled, approximately 9.5 to 1 slope with bearings 250mm apart:

RollinPrototype.mp4

Some beaches are about 10:1, all slips I've used are steeper. The prototype looks promising and the next stage will be a 2.5m ladder of rollers.

Wooden sides can stop the keel falling off the rollers. I drilled out the Unistrut 10.7mm slots to 12mm, which was tricky using a drill press and breaks the galvanised seal. Another option is filing 12mm grooves in hardwood to clamp the rods on the top of the Unistrut.

I reckon a roller every 250mm (10") is a starting point - about 2m from skeg to front of CB case is flat then she curves upwards. 8" rollers come in a variety of diameters, I need to find a source with continuity of diameter in case I need to order more.

As the keel is Iroko capped with stainless plate harder rollers could be used. Rubber rollers compress over winter and jam when rotated; although spreading the weight over 11 instead of 3 rollers should reduce compression significantly.

I wonder if wooden rollers would stand up to the loads? If they did then Graham can grow them 4m long.

Ah Paul, you have an old Vanguard mast to recycle.

-Paul

[alopenboat]

On 11 Feb 2021 at 6:04, Paul (admin) [via UK HBBR Forum] wrote:

>
>
> Al's trailer has clever copper-stainless bearings. Take an 8in roller
> with 16mm  bore, insert 15mm copper pipe and then 12mm stainless rod
> and it spins freely:
>
> <http://uk-hbbr-forum.967333.n3.nabble.com/file/n4032034/20210211_1156
> 23_resized_1.jpg>

I recommend grease on the metal to metal surfaces.

> Rubber rollers compress over winter and jam when rotated;
> although spreading the weight over 11 instead of 3 rollers should
> reduce compression significantly.

LJ (640kg) sits on 2 sets of rollers all the time when not afloat.
After 18 years there is no sign of the rollers distorting.

--
Sail when you can, row when you must, motor only
when you have to be at work in the morning.

Alastair Law
Yeovil, England.
<http://www.little.jim.freeuk.com>



--
This email has been checked for viruses by AVG.
https://www.avg.com

[Paul H (admin)]

alopenboat wrote

I recommend grease on the metal to metal surfaces.

> Rubber rollers compress over winter and jam when rotated;

LJ (640kg) sits on 2 sets of rollers all the time when not afloat.
After 18 years there is no sign of the rollers distorting.

Thanks Al,
Glad to know your rollers are fine after 18 years.

MB's old keel was made from rounded oak trim 1.5in wide from a bookcase bought in America. I ripped it down the middle, each half capped the centreboard plywood side. In hindsight the footprint was too narrow, creating extreme pressure for the centre roller.
Now the Iroko capping is about 55mm each side, so much less pressure.

I remember you telling me to grease the roller bearings. Will definitely do that.


Prototype 2 will have 63x38mm CLS to guide the keel on the rollers, continuous from the rear forwards. Better to have a softer surface to knock against, whilst making every pot hole bigger ha ha.

Paul

[Port-Na-Storm]

Woodman Spare That Tree.

Your old mast is likely made of spruce or some other lightweight softwood which could be repurpoused as an unstayed mast for a small lugger.

It will probably be too soft for rollers in any case.

Rubber is your friend.

Sent from my Xperia by Sony smartphone

---- Paul (admin) [via UK HBBR Forum] wrote ----

Al's trailer has clever copper-stainless bearings. Take an 8in roller with 16mm  bore, insert 15mm copper pipe and then 12mm stainless rod and it spins freely:



I have prototyped a ladder of rollers for MilliBee's trailer, with Unistrut galvanised U channel 40mm x 40mm and stainless copper bearings. Here is a short video clip of a 22kg battery on a wooden sled, approximately 9.5 to 1 slope with bearings 250mm apart:

RollinPrototype.mp4

Some beaches are about 10:1, all slips I've used are steeper. The prototype looks promising and the next stage will be a 2.5m ladder of rollers.

Wooden sides can stop the keel falling off the rollers. I drilled out the Unistrut 10.7mm slots to 12mm, which was tricky using a drill press and breaks the galvanised seal. Another option is filing 12mm grooves in hardwood to clamp the rods on the top of the Unistrut.

I reckon a roller every 250mm (10") is a starting point - about 2m from skeg to front of CB case is flat then she curves upwards. 8" rollers come in a variety of diameters, I need to find a source with continuity of diameter in case I need to order more.

As the keel is Iroko capped with stainless plate harder rollers could be used. Rubber rollers compress over winter and jam when rotated; although spreading the weight over 11 instead of 3 rollers should reduce compression significantly.

I wonder if wooden rollers would stand up to the loads? If they did then Graham can grow them 4m long.

Ah Paul, you have an old Vanguard mast to recycle.

-Paul

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