Oarlock pictures

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Oarlock pictures

Post by topherdawson on Fri Dec 02, 2016 2:27 pm

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Re: Oarlock pictures

Post by Don Currie on Sun Dec 04, 2016 8:20 am

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Re: Oarlock pictures

Post by topherdawson on Sun Dec 04, 2016 9:47 am

This seems simple and well thought out. It rests the weight of the oar on the gunwale but does not take the pitch reference from the gunwale as the wear strip is narrow and radiused. So the pitch reference comes from the pin without needing a plate. Simple and easy to make.

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Re: Oarlock pictures

Post by Don Currie on Mon Dec 05, 2016 7:54 am

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Hopefully this message will have images attached or showing or somesuch! This system, as Topher has commented is light and simple, and importantly to me for long morning rows, QUIET! Those flat plates clonking away like a square wheel annoyed me no end when I started rowing the St Ayles. Other thing to note about the photo is the gunwale pad the oar sits on - by giving it a nice radius you further reduce noise, and it wears more evenly. Gearing moves in 75mm steps, but that could probably be reduced a bit for those who want a close ratio gearbox!

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Re: Oarlock pictures

Post by topherdawson on Wed Dec 14, 2016 9:19 pm

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This is a round ended pin supporting the weight of an oar. The end of the pin locates in one of three dimples in an 18mm ply plate glued or screwed to the top of the oar. There is a keeper which encloses the pin and is spaced away from the oar by spacers at its ends and maybe between gears.

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Re: Oarlock pictures

Post by john mcintyre on Fri Dec 23, 2016 4:17 pm

I don't like this design because:

1. I think the oar will jump out of the 'dimples' i.e. not reliably stay in the gear selected.

2. The wear strips are internal and hence will be more difficult to inspect and repair.

3. There will be a higher stress/BM on the aft 'beam' / 'face strip' of wood forming the slot compared with a whole un slotted oar bearing against a pin or oarlock.

4. The oar will be harder to make than a normal oar and will need to be made with greater precision even assuming problem 1. does not clobber the design.

John

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Re: Oarlock pictures

Post by topherdawson on Fri Dec 23, 2016 5:19 pm

Hi John,

This sketch is actually not of a slotted oar. In this version the whole oar is on the left of the pin and the timber to the right is a separate keeper like Don's, held on to the oar with screws (not shown) through spacers. Undoing the screws allows easy replacement of the plastic wear strips.

So it is like Don's except the weight of the oar bears on the top of the pin.

I agree that the dimples alone would not hold the oar in gear but if between every dimple there was a substantial screw then it would not jump out of gear. After all our Ullapool oars only have to rise 15mm to jump a gear but they seldom do.

Here is a revised sketch:
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Crail oars and rowlocks

Post by David Fraser on Sat Dec 24, 2016 2:04 pm

I have attached four photos of our “wing and pin” system which has served us well in Crail since new and for four years now without one breakage. The pin is a 30mm diameter x 210mm oak shaft, glued into an oak block which is then secured on top of the gunnel with two bolts, the heads being recessed in the block. To prevent the pin from wearing, a short length of plastic plumbing pipe slipped over the pin, makes a good protective sleeve. To comply with rules, the pipe is removed when racing and a thin plywood packer is then taped to the inside of the oar wing to compensate for the slightly reduced pin diameter, thus stopping any “clunking”. Thin wooden washers sitting on the base of the pin also help reduce the wear. (And serving a dual purpose, two or three washers also raise the oar in a heavy wave to reduce the chance of catching a crab). The base of the oak block has been shaved at an angle so when it is seated on the gunnel the pin is vertical. The pitch is also fully adjustable in all directions by using simple packers where required.

A length of heavy duty shrink-wrap sleeving is applied to the oars, which again eliminates wear. The sleeving wears, but only needs replacing every two or three years. The wing is secured to the oar with a thin chord whipping, but we recently experimented with parcel tape instead, which, surprisingly, does the job perfectly and is extremely quick and easy to apply. No screws, bolts or any other fixings are used, thus retaining the integrity of the loom and totally avoiding water penetration. The gearing can be changed by securing a small block of wood inside the elbow of the wing, effectively increasing the inboard length. Lastly, but very importantly, the oars can be quickly and easily drawn inboard to avoid collision or when navigating in close quarters.

The system has never broken despite four hard seasons and is well liked and managed by all our rowers, (and others), in comparison to other systems we have tried in other boats. It has been successful competitively and we fully expect the oars and pins to last many years. Over winter, re-varnished and re-painted, they look like new and are indeed a joy to behold, showing almost no signs of wear or potential failure. I’m not qualified to provide any technical stuff – I used to call it a “kaboodle”, but “wing and pin” is as good as it gets.  But I hope that I have provided an insight into our workings.

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Re: Oarlock pictures

Post by topherdawson on Sat Dec 24, 2016 3:40 pm

This system has served you well David. Thanks for providing the photos. Like systems with buttons it needs the rower to maintain an outward pressure to prevent the oar drifting inwards, and it only has one gear. It does as you say allow the oar to be quickly drawn in to prevent damage from harbour walls or other boats.

Am I right in thinking the oar gets its pitch reference from the pin, not the gunwale? And where does the weight of the oar rest, on the washer or the oak block?

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Re: Oarlock pictures

Post by David Fraser on Sat Dec 24, 2016 4:10 pm

By trial and error the pitch has been adjusted by inserting thin packers strategically placed in between the oak block and the gunwale.

The oar rests on the wooden washer. In very calm conditions, the wooden washer is swopped for a thin plastic washer, made from the off-cut of the shrink-wrap sleeving. The main object is to minimise wear and maintenance.

BTW, we have found that very little outward pressure is required to prevent the oar drifting inwards. In practice, the rower is barely aware, if at all, of pushing outwards.

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Re: Oarlock pictures

Post by topherdawson on Sat Dec 24, 2016 4:25 pm

What pitch do you aim for? 4 degrees top edge towards the stern seems to work for us but we have not done much experimentation.

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Re: Oarlock pictures

Post by Ian Mills on Sat Dec 24, 2016 4:43 pm

Just to add to what David has already said -

Regarding the lack of gears - we have arrived at a gear which works well for us with our particular set up of oars/blades/rigging, by changing the position of the block. This has then been tweaked race to race (eg for headwind) using the packers as described.
I agree, as Topher has alluded to, that this may not be ideal for other clubs who have members who prefer a higher gear. (We have a small group who are easy to mould!!)
However, this could easily be improved by having larger packers - fixed in place by screws (as ours are already) or whatever.

We are very concerned with the safety issues of having oars which are fixed in place and much prefer the ability to retract oars quickly, whether avoiding clashes going around a buoy turn, or on a busy start line, or getting too close to the rocks of Craig Leith etc.

There is no other branch of competitive rowing where oars are fixed.

As David says, the difficulty involved with keeping the oar against the pin is minimal.

Our system is fully and easily micro adjustable for pitch in all directions, as well as height by placing washers under the oar.
Any system which might be designed where the oars are resting on the pin, means height adjustment 'on the fly' is not possible.
(eg if the sea get rough during an outing, we usually increase the height of the oar with packers carried in the boat).

Ian


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Re: Oarlock pictures

Post by Ian Mills on Sat Dec 24, 2016 4:46 pm

Pitch?
- Not sure exactly - would have to measure it somehow. I'll try and find a photo. We've just done it experimentally. We fiddle with lateral pitch quite a bit also - a few degrees perhaps.
We try and build our oars to zero pitch but in practice I think there is maybe a degree or two of positive pitch built into the blades. (Oh no.. another variable!!)
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Re: Oarlock pictures

Post by topherdawson on Sat Dec 24, 2016 4:57 pm

As to the safety issue, only about 15mm vertical movement of the oar is needed to change gear or haul it in altogether with Ullapool's gear system, which is in the form of notches in the wear plate under the oar which engage in the bottom bar of the swivel.

The rower does not need to cantilever the whole weight of the oar to lift it, They only need to raise the handle end and let the blade float.

I'm not suggesting this system for the standard oarlock because it is time consuming to make and too complex for many clubs. But Don Currie's system also only needs lifting the handle to release the oar, as does Dundrum's and my ball ended pin.

As to gears, I think that oars need more than one because conditions and crews change. Ideally I think it should be a quick and easy operation not needing tools or additional components.

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Re: Oarlock pictures

Post by Ian Mills on Sat Dec 24, 2016 5:13 pm

Yes, I agree a quick release system for us with our current system would be much better if possible - we'll work on that!

Happy Christmas to all!!


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Re: Oarlock pictures

Post by topherdawson on Sat Dec 24, 2016 5:22 pm

Happy Christmas to all!

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Re: Oarlock pictures

Post by Ian Mills on Thu Dec 29, 2016 9:13 am

'Hope everyone ate and drank too much over Christmas - as is customary!

I've thought up a simple fix for the lack of different gears in our system and one which allows easy changing of gears in boat with no extra tools or additional components required:

Instead of the small (18 mm ply) packers on the gearing block (see photo in David's post above), we can make a short dowel or rounded block which would slide along the oar between the 'keeper' and the oar shaft. Drill a hole through it and countersink (and glue) a 6mm machine screw into it (from the underside) which will slide along a slot cut into the 'keeper'.
A wing nut on the outside of the keeper will lock it in place and make adjustment during an outing easy.  
Fairly simple to build and should have most of the necessary attributes. The design is very similar to Don's system also, but now will have infinitely adjustable gear ratio.

I will be making this for our oars this winter as an improvement to our current set up.

We still prefer the open ended keeper and feel that a system where the oar can be retracted without thought in the event of a collision is preferable and safer to having to physically lift the oar handle to clear the pin and then pull in the oar in.

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Re: Oarlock pictures

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