What can we agree on?

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What can we agree on?

Post by topherdawson on Thu Dec 01, 2016 9:50 pm

I am going to write some basic facts about skiff oars which I think are fairly uncontroversial but if you disagree with them please reply to this.

1   The St Ayles Skiff is a rendering of a traditional Fair Isle skiff which used to be rowed with fairly short oars, 9 or 10ft (3m). The St Ayles is rowed with longer oars and many users have had a problem with clashes, i.e. hitting the rower in front with the handle of the oar.

2   Standard sliding seat sweep oars are 3.6m to 3.7m and if rowed at a gearing between 2.7 and 3 cause the rowers to sit near the centreline of the skiff, which causes clashes. They can be geared to a long enough inboard to prevent clashes but this results in a very low gearing of about 2.2.

3   The space between St Ayles seat centres on the plan varies around 1m, but by moving the seats forward it can be made up to 1030mm which helps but does not solve the clash problem.

4   Factors which affect the clash problem are: length of inboard (distance from the end of the oar handle to the pivot), how far forward the rowers reach, how wide the rowers' bodies are, how good their timing is, and whether the seats have been moved further apart. In my opinion (comments welcome) oars 2 and 3 need an inboard of at least 1125mm to avoid clashes.

5   Two known solutions are to be seen in the St Ayles fleet, short oars and long oars.

6   With short oars, with an inboard of less than 925mm, the rowers sit staggered away from the centreline towards the oarlock. When they reach for the catch, their oar handles pass outboard of the rower in front. All 4 oars can be the same length and design. The oars are light, cheap, and easy to row with. Boatie Blest, Seil, Luing and Portsoy use this solution.

7   Most of the rest of the fleet use long oars. Oars 2 and 3 in the middle of the boat are made with an inboard of 1.125m or longer, and the rowers are staggered away from the centreline away from the oarlock. When they reach for the catch, the oar handles are towards the oarlock of the rower in front. Oar 1 at bow is usually a bit shorter because the boat is narrower at bow, and the stroke oar 4 is shorter still because the stroke's feet are in the narrow part of the stern and having a longer oar would twist the stroke's spine.

8   Because most clubs think longer oars are faster with most crews, we will need to develop a long oar. Because shorter oars are easier to make light, we should concentrate on the longest oars which are the hardest to get right.

9   Making wooden oars longer than the sliding seat standard of 3.7m is difficult because the bending moment increases and so they have to be wider and deeper as well as longer, making them heavy. Heavy oars can be well balanced but tend not to be, and as a result are often hard to row with, as they need many kilograms of downwards force at the handle to get the blade out of the water. I am calling this force UHF (Unbalanced Handle Force).

10   Carbon or glass fibre tubes are a light and stiff way to make oar shafts but the clubs have said very clearly that traditional looking timber oars are what they want, so I am taking it that we are not free to design a composite resin/fibre oar. (comments?)

11   Clubs also want an oar which is simple to build, and reasonably cheap to buy the materials for, although they are less unanimous about this.

12   We will have to take a view about how complex the build of our oar can be. Some think that hollow shafts are too complex, others not. Some think using more than one type of timber is too complex, others not.


Last edited by topherdawson on Fri Dec 09, 2016 12:04 pm; edited 1 time in total

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Re: What can we agree on?

Post by Don Currie on Sun Dec 04, 2016 7:30 am

Hi all, re issues 11 and 12, I may as well declare early that I'm a real fan of hollow oars. Simple to build is not the same as quick to build. Sure hollow oars need more steps to glue them up, but you use significantly less material (thus cost is reduced), and you can achieve nice balance without having to resort to expensive timbers like spruce. We're using cheap and cheerful hollow rectangular oars, 4.5M long, with a UHF of about 3.2kg. I'll try to post some drawings of them in the drop box. But long story short, if a group can build a St Ayles skiff with all the changing bevels that that entails, they can build a simple hollow rectangular oar.

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Re: What can we agree on?

Post by John Irvine on Wed Dec 07, 2016 6:08 pm

This is where we've got to at North Berwick:
- We started with round Admiralty style oars between two pins. We didn't like the variable pitch and the tendency for the oar to slide outboard. We were also breaking pins frequently.
- We have tried the pin and plate system. Again we experienced variable pitch as the pin and plate wore. We also didn't like the oars being fixed in position as it was more difficult to pull them in to avoid a collision.
- We have settled on a wooden gate, made of layers of marine ply, rotating on a vertical wooden pin. Most of the time we use a plastic washer between gate and gunwale, but use a wooden one for regattas. [We would like the rules loosened to allow the plastic washer to be used at regattas].
- We now use an oar with a square section at the gate, with wooden stops beneath a PVC sleeve preventing the oar slipping outboard, but with no stops preventing the oar being pulled inboard.
- Our early oars were made of Douglas fir. They were heavy. We have moved to Sitka spruce. We've been purchasing straight grain, knot free, blanks from Roberts in Bristol. The wood is quite expensive: approx £100 each oar.
- Our oars are solid, crafted with planes and sanding.
- We use 9mm marine ply for a Macon shaped flat blade, which is glued into a slot in the spruce loom.
- We have had breakages, mainly for two reasons. 1. Some people were over zealous with their planing and sanding and made the handles too long. The resulting oar was too thin at the half way point between the handle end and the gate. 2. We converted the pin and plate oars to sleeve and gate. Despite removing the screws from the plates and filling with epoxy, the oars were weakened and snapped at the gate.
- We now have shorter, fatter handles. These are stronger and have the added advantage of promoting good rowing by stoping people gripping too hard.
-We have always sat centrally in line and those of us with longer reach have been restricted at the catch by the person in front. We have partially solved this by moving the seats further apart. [I have rowed in other clubs' boats with shorter oars, requiring the rower to sit closer to the oar side; and found it difficult to get much power on]
- We have settled on a 3:1 gearing. Our gearing is measured to the inside face of the gate. [I realise there are different schools of thought on how to measure gearing and that probably we are not actually at 3:1. But the main point is to be consistent throughout the set of oars].
- We use 14' oars at bow, two and three: 3'6" inboard, 10'6 outboard.
- Some prefer a shorter oar at bow, but that has to be pulled higher at the finish and the handle end is more likely to hit the two rower in the back. 3'6" inboard is the maximum at bow,; longer results in a painful collision of outside elbow and gunwale.
- The stroke oar is shorter, because the boat is narrower in the stern. We use 12'6", still geared at 3:1. This tends to push the stroke off centre, away from the gate, but a shorter oar leads to squeezing the boat at the catch.
- Some people complained (no, really) that the oars felt heavy outboard. We made a set of 13' oars geared at 2.7:1. Annoyingly, the complainers didn't use them because they had to pull higher at the finish.
- We have found that all crews have adapted to the 14', 3:1 oars. That includes the junior crews who rowed successfully at the Worlds.
- The next development is probably hollow looms and 15' oars in the two and three seats to allow some offsetting.
[We are constrained by the loss of our workshop which we had to vacate about a year ago]

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Re: What can we agree on?

Post by topherdawson on Wed Dec 07, 2016 6:35 pm

That's very interesting and informative John. I hope you will still fill in the oar measurement form because the UHF and deflection are important.

Would I be right in thinking your swivels are made from three layers of 18mm ply? Because if so one would need to add 1 and a half layers of 18mm = 27mm to your inboard to get to the pin centre, making it actually 1093.8mm. That would make your FISA gearing = 3173.4/1093.8 = 2.901.

I reckon that an inboard of at least 1125 or better, 1140, is needed to offset the rowers far enough to avoid clashes so going for 15ft oars would help a lot. At a FISA gearing of 2.9 you would have an inboard of 1172mm so in the clear.

In correspondence with Finlay Robertson and Don Currie we have agreed that variable blade lengths make FISA gearing a fairly inaccurate way to calculate gearing.

Instead we have decided to calculate true gearing, which needs us to know how long the blade is so we can calculate how far in from the end of the oar the centre of pressure is. This is why the oar measurement form has that to fill in.

If you went for hollow oars would someone in your club make them, or would you buy them in? There is a discussion going on here about whether hollow shafts are too hard for club oar makers.

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Re: What can we agree on?

Post by Norfolk boy on Wed Dec 07, 2016 8:14 pm

How do I find the Oar Measurement Form?

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Re: What can we agree on?

Post by topherdawson on Wed Dec 07, 2016 8:20 pm

Hi Adrian,

Sorry I sent the link to the form in an email sent out before you joined. It is in the Dropbox folder (link to that on the front page of this forum) under oar documents.


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Re: What can we agree on?

Post by Norfolk boy on Wed Dec 07, 2016 11:10 pm

Dropbox folder empty.

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Re: What can we agree on?

Post by topherdawson on Thu Dec 08, 2016 10:43 am

Hi Adrian,

The Dropbox site seems to have been updated and I agree that clicking on the link does not work, but if you copy and paste the link into your browser address line, that does seem to work.

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Re: What can we agree on?

Post by Finlay Robertson on Fri Dec 09, 2016 9:54 am

Topher,

I’ve taken some time to read through your first message and have some comments to make. (I’m quite good at playing Devil’s Advocate so don’t take any of my challenges personally!)

Fair Isle and St Ayles Skiff
I can see what you’re trying to say in Point 1 and the comment about oar length is certainly valid, but I think that describing the St Ayles Skiff as a ‘faithful rendering’ of a Fair Isle Skiff is a bit of a stretch – it has more rowers, a hull that’s gone through at least one significant revision, different materials and construction methods, and (normally) no rig. I consider it to be a modern interpretation of the Nordic-influenced boats once commonly used in fishing villages throughout Scotland, drawing inspiration from the Fair Isle Skiff but most certainly remaining its own design.

Lengths Quoted
Sometimes you’re referencing the length of the whole oar; sometimes the inboard length. Wherever you’re discussing the clashes between rowers (Points 2, 6 and 7), it’s the inboard length of the oar that’s important and should be quoted – not the length of the whole thing. I know this is implied but it’s not especially clear, and I think we should agree on a standard to avoid confusion later on. Optimal gearing is another matter entirely and is best kept in a separate discussion.

Inboard Length and Seat Spacing
Issues regarding inboard length and seat spacing have to be grouped together, as they are intrinsically linked. As such, I think that Point 5 has to be broadened. The aim is to prevent clashes between rowers, for which there are 4 main solutions:


  • accepting the restricted space (okay, this isn’t really a solution!)


  • deviation from the original plans to provide wider spacing of seats (as per Point 3); this is probably the  most common solution used


  • shorter inboard lengths (as per Point 6)


  • offset seating with a longer inboard length (as per Point 7); this can be done instead of or in addition to wider seat spacing*


The experience from my own club indicates that adjusting seat spacing is a far more complex task than one might expect (it kept both of our bosuns entertained for many weeks!) – certainly it’s a lot more difficult than a basic oar build**. Since standardisation of oar design will also require a standardisation of seat spacing / rower positioning (and thus modification of thwarts, seating, knees (if fitted) and footrests on some existing skiffs), we need to remember that the merits of a ‘simple’ oar design are not so clear-cut – any proposal we make will require substantial boatwork to be carried out throughout the fleet. In view of this, I’ve started an additional topic in the forum where this can be discussed.

*I’m not sure about your comment in Point 7 stating that most of the fleet stagger – my impression is that most sit on the centreline, albeit with widened seat spacing; do we have any data on this?

**In terms of more involved oar builds, one could argue that building a laminated oar is not dissimilar to laminating the stems or gunwales of a skiff; or that scarfing a denser inboard length to serve as a counterweight is not so different to scarfing plywood planks together to make up the boat’s strakes; clearly this needs further discussion!

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Re: What can we agree on?

Post by topherdawson on Fri Dec 09, 2016 11:09 am

Thanks Finlay for this very detailed post, and no offence taken at all.

Finlay Robertson wrote:Topher,

I’ve taken some time to read through your first message and have some comments to make. (I’m quite good at playing Devil’s Advocate so don’t take any of my challenges personally!)

Fair Isle and St Ayles Skiff
I can see what you’re trying to say in Point 1 and the comment about oar length is certainly valid, but I think that describing the St Ayles Skiff as a ‘faithful rendering’ of a Fair Isle Skiff is a bit of a stretch – it has more rowers, a hull that’s gone through at least one significant revision, different materials and construction methods, and (normally) no rig. I consider it to be a modern interpretation of the Nordic-influenced boats once commonly used in fishing villages throughout Scotland, drawing inspiration from the Fair Isle Skiff but most certainly remaining its own design.

OK it's not a faithful rendering when you look at all those variations, but it does have the same sort of seakeeping abilities. Coincidentally I was talking yesterday to a woman brought up on Fair Isle and she called the local boats "yoles" and said they were always taking in water over the gunwales!

Lengths Quoted
Sometimes you’re referencing the length of the whole oar; sometimes the inboard length. Wherever you’re discussing the clashes between rowers (Points 2, 6 and 7), it’s the inboard length of the oar that’s important and should be quoted – not the length of the whole thing. I know this is implied but it’s not especially clear, and I think we should agree on a standard to avoid confusion later on. Optimal gearing is another matter entirely and is best kept in a separate discussion.

I will try to tidy this up. There is a separate Gearing discussion. The trouble is that clashing is intimately bound up with gearing. There are skiff clubs in Perth Australia and Tasmania who are happy to row with 3.7m carbon oars and can't see what all the fuss is about. It turns out they are rowing at a FISA gearing of 2.1 - 2.3 !!!!!! This would not suit the rest of us.

Inboard Length and Seat Spacing
Issues regarding inboard length and seat spacing have to be grouped together, as they are intrinsically linked. As such, I think that Point 5 has to be broadened. The aim is to prevent clashes between rowers, for which there are 4 main solutions:


  • accepting the restricted space (okay, this isn’t really a solution!)


  • deviation from the original plans to provide wider spacing of seats (as per Point 3); this is probably the  most common solution used


  • shorter inboard lengths (as per Point 6)


  • offset seating with a longer inboard length (as per Point 7); this can be done instead of or in addition to wider seat spacing*


The experience from my own club indicates that adjusting seat spacing is a far more complex task than one might expect (it kept both of our bosuns entertained for many weeks!) – certainly it’s a lot more difficult than a basic oar build**. Since standardisation of oar design will also require a standardisation of seat spacing / rower positioning (and thus modification of thwarts, seating, knees (if fitted) and footrests on some existing skiffs), we need to remember that the merits of a ‘simple’ oar design are not so clear-cut – any proposal we make will require substantial boatwork to be carried out throughout the fleet. In view of this, I’ve started an additional topic in the forum where this can be discussed.

In my opinion (opinion alert!) the furthest forward that seat 1 (bow) can be moved is till its aft edge is level with the forward face of its frame. I hope we agree we can't move the frames. This is a move of 118mm. The plans for some reason show a different spacing between adjacent frames at different seats. If we keep the stroke seat in the same place, move the bow seat 118mm forward, and space seats 2 and 3 evenly, we get 1030mm between centres. This helps but it does not cure the clash problem.

*I’m not sure about your comment in Point 7 stating that most of the fleet stagger – my impression is that most sit on the centreline, albeit with widened seat spacing; do we have any data on this?

Sitting on the centreline seems to me to cause clashes even with increased seat spacing, and that's why long oars and short oars are two different camps with no middle ground.

**In terms of more involved oar builds, one could argue that building a laminated oar is not dissimilar to laminating the stems or gunwales of a skiff; or that scarfing a denser inboard length to serve as a counterweight is not so different to scarfing plywood planks together to make up the boat’s strakes; clearly this needs further discussion!

I agree that scarphs and laminating are skills needed on the boat hull. What is still in doubt is whether it is fair to ask people to take on making an oar jig and then accurately positioning slender floppy strips covered in glue. Probably it is doable.

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Re: What can we agree on?

Post by Finlay Robertson on Mon Dec 12, 2016 10:29 pm

Yes, I'm inclined to agree that the proposition of moving the frames might be met with a bit of resistance!

In North Berwick, we've moved the aftermost to the back of Frame 4 as well as moving the forrardmost seat to the front of Frame 1; I believe that the centre-to-centre spacing is in the region of 1080 though it varies slightly between boats. We row on the centreline with "middle ground" inboards and as long as everyone leans all the way forwards, clashes are generally avoided (except maybe with the end of the tiller, but that's another story!).

Having said that, my wife and I had the pleasure of visiting Anstruther at the weekend and they were kind enough to take us out rowing; I'd forgotten just how much room is available with their offset system.

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Re: What can we agree on?

Post by topherdawson on Tue Dec 13, 2016 9:51 am

Hi Finlay,

The master spreadsheet is here:

[You must be registered and logged in to see this link.]

If you look at the inboards especially of oars 2 and 3 you will see a remarkable similarity, which tells me that people have worked out how long the inboards need to be to avoid clashes.

Because clubs are rowing at different gearings, and have different blade shapes, the overall lengths of the oars vary a bit, but I'd say there is a fair degree of unanimity that the inboards need to be in the region of 1150 -1200mm.

I'm hoping that John Irvine will measure your oars soon so we have numbers for them.

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Re: What can we agree on?

Post by Ian Mills on Wed Dec 14, 2016 5:01 pm

Crail Oars:

The design of our oars (originally built in 2012) was based on a sketch which I received from a guy at the oar makers Suttons in England.
They had built the oars which I rowed with in the 70s before carbon fibre oars took over as weapon of choice for river rowers. They still make fine oars now.
[You must be registered and logged in to see this link.]
Originally, rowing oars were made from a hollow box of sitka spruce with a layer of Ash on the forward face. The oars had a 'D' section which allowed precise setting of the oar against the (plastic) gate. The rounded nature of the aft face allowed smooth feathering and saved some weight where it was not required.  (See also Topher's notes on the engineering of an oar.)

So, we built a hollow box of Sitka spruce which was reinforced on the front and backs with Ash. The thickness of the 'box' sides was mostly 12 mm. We used 8 mm ash on the front and 6 mm on the back (aft) face. (Laminated to 12 mm Spruce.) We tapered the ash to nothing along the length of the loom.

The ash adds strength where it is needed most (ie on the fore and aft of the 'beam').  
Ash is not only a fairly strong timber but it bends smoothly when loaded. Ash is the material still used for hockey sticks, tool handles etc etc for this reason.

Sitka spruce has an excellent strength to weight ratio as well as good durability and takes varnish well. It has been used by professional oar and mast builders for many, many years.
Adhesive – my received advice was to use Resorcinol. It is not only fully weather proof (used for construction of marine plywood) but it does not fail easily under bending load. It is what is used by professional oar/mast builders. Resorcinol is better than epoxy for this purpose.

The total cross section of our oars was about 65 mm square at the pin. We rounded the aft face to a 'D' section.
Looms are tapered to approx 50 mm x 35 mm at the neck.
(I will add drawings as soon as time allows.)

The oars are not the lightest in the fleet , but they are quite stiff and have been extremely durable. We have not had a breakage yet, despite 4 years of fairly hard use. We are happy with the balance. UHF is around 4 – 4.5 kg – perhaps a little high, but not by much and only small children would find the oars difficult to use. The oars behave well in all conditions.

Length – we have mostly used 13'10” for 2 and 3 and 12'10” for stroke and bow.

If you want a good design, proven both historically and in the skiff community, then this is close to optimal in my opinion.

Last year we built some 15' oars for positions 2 and 3 for the Worlds.
(Also a 13'11” oar for bow.) We made the longer oars slightly deeper fore and aft at 68 mm.  i.e. 68 mm x 60 mm at the pin.
Rather than planing a round 'D' section to the rear corners, we instead planed off the corners to a simple bevel along the length of the looms as far as the blades. This was simpler to achieve compared to fully rounding the looms. (Though not as pretty!)

The longer oars proved useful for taller rowers who could benefit from the extra reach (when sat overlapping on the seats). However they were rejected by our successful Over 40s Girls who found them harder to manage, especially in rough water and found them awkward to extract cleanly. (Though this was improved a little by moving the pins stern-wards.)

I believe, therefore, that it is better to spread the seats out more (as discussed by others already) and keep the oars' maximum length to around 13'10” to 14' than to make unnecessarily long oars which are not as efficient as some believe.

Although we thoroughly enjoy the process of building hollow oars, I accept that it is not for everybody.
Considerable care is required whilst selecting and laminating timber. However, considerable care is required for all aspects of successful oar construction, hollow or not.

A simpler to build  version of our oars could be to make a solid sitka spruce loom, but also laminating 8 mm spruce to the front face.  65 mm square at the pin gives a strong and stiff oar which does not bend excessively in either plane.
Plane the aft face corners off on the outboard, as described above.
I believe that this would be a great design: It is based on a proven design which has been used successfully by a great many oarsmen over the decades.
The ash lamination adds a great deal of stiffness and strength.

Another option is to encourage builders to build hollow oars themselves or buy ready made oars - to an agreed design.
I know from my emails with Suttons that they were keen on getting into the Scottish skiff market!
By the time we had paid for well selected timber and had it machined to our specs, the cost approached what we would have had to pay for a set of commercial oars. (Over £1,000)
Though some clubs seem keen on not spending much money on oars, if you want oars which last well and are easy and enjoyable to row with, then money/time must be spent!

Gearing – We row at quite a low gearing.
Around 1:2.6 to 1:2.65.
We have a lighter gearing at Stroke compared to the other seats as there is more load on the stroke due to the increased angle of arc.
Our crews are often competitive against bigger stronger crews for this reason. I do not agree with the perception that 1:3 is optimal. This would be way to heavy for our crews.

We at Crail do not believe that an absolute standard design should be adopted, rather that clubs should have at least some freedom to decide what length/weight/gearing/stiffness etc of oar to use for particular crews – in much the same way that already exists in all other forms of racing.
What is optimal for one crew will not be optimal for another.
For example all slidy seat rowers now use carbon tubes, with 'chopper' blades, but with a variety of sizes of blades/lengths of oars.
Gig rowers use hollow spruce oars with a traditional shape blade, but also use different lengths of oars etc to suit.
However, agreement on what works well and options and/or limitations of blade shape/cross section/length/gearing etc is clearly important.

Ian

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Re: What can we agree on?

Post by topherdawson on Wed Dec 14, 2016 7:22 pm

Hi Ian,

Thanks for that long and informative post. Looking at the spreadsheet

[You must be registered and logged in to see this link.]

the inboards of your front three oars (stroke can't clash with anyone except the cox) are all over 1180mm which ought to be free of clashes, even without the 18mm spacer you used at the Worlds.

UHF of 4kg is pretty common but probably more than optimal. In a conversation with Robert Graham of Dundrum, he reckoned 2 to 2.5kg was optimal. I'm going to start a topic about UHF separately.

Spruce is obviously the oar material of choice, but very expensive. I made a design spreadsheet which is not perfect but which computes strength and stiffness.

[You must be registered and logged in to see this link.]

It confirms that stiffness, not strength, is the limiting factor. So the superior strength of spruce is not needed if the oar is stiff enough, and Western Red Cedar is nearly as stiff and quite a bit cheaper.

Does the hollow in your oars extend to the inboard? Ours does but I wish it didn't. Your solid oar with the aft corners taken off is an approximation to the trapezoidal oar. This is the spreadsheet for that:

[You must be registered and logged in to see this link.]

Gearing: you do row at a low gear but I feel we could accommodate everyone with a choice of three gears: 2.7, 2.85 or 3. That just means three notches or holes or whatever. This is something we can negotiate, but I agree with you that the rowers need to be able to suit the gearing with the conditions and the crew easily and quickly.

On another post on this forum

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Don Currie suggests putting the pins at 2 and 3 in blocks fastened to the inside of the gunwale, and upright, thus moving them in by up to 70mm. This could mean the inboard could be shorter by 70mm which in turn would shorten the whole oar by 250 - 280mm. This is a big gain and could mean the bow oar could be the same length as 2 and 3.

I think the rule about the pin being on the gunwale could be changed if we made a good case.

This is not an outrigger but an inrigger, and can't be too big or the oar will hit the gunwale when angled downwards. What do you think?

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Re: What can we agree on?

Post by Ian Mills on Thu Dec 15, 2016 10:36 am

UHF:
we are pretty happy with our UHF as it is.
I could have reduced this on the latest oar build by making lighter blades, but decided against as we were pretty happy with the 'feel' of the oars as they were originally (around 4kg)
I'll respond better on your post about UHF when it appears in due course.

Spruce/Western Red Cedar:
I just went for what has been proven to work well in a robust manner.
Nothing innovative – just copying what has been done by Suttons/Collars etc for many years.
Cost – at the time we decided to build the best oars we could which would last for many years.
We'd rather spend twice as much money on something and do it only once than skimp on cost and end up doing it again later because it has broken.

My thoughts are that WRC is prone to splitting over time?
Personally I'd rather stick with Spruce for that reason alone.

Okay, some clubs want cheap oars but cheap oars won't be as good as well thought out oars where time/money has been spent. Hmmm...!

Don Currie's idea and 'In Riggers':

I agree with your comments on his post.
I love our current system where the pin is mounted vertically in a block on top of the gunwale with 6 mm bolts. It is easily adjustable for pitch in forward and lateral directions with simple packers. Also easily removable and very simple to move fore and aft by moving bolt holes.
I think Don's suggestion, whilst a great idea, would be difficult for all to adopt compared to the systems used by most people currently.

Ian

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Re: What can we agree on?

Post by topherdawson on Thu Dec 15, 2016 11:21 am

Hi ian,

The UHF post is here:
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As you say I'm a big person and not unduly bothered by our UHF's of around 4kg but experimenting with wrapping our anchor chain round the handle I did like it better with 1kg of chain, so 3kg UHF.

I suspect that women would like it lighter but we all get used to things the way they are. What do your forearms weigh?

Our problems with oars stem from the need at 2 and 3 to have long inboards. Inriggers deal with this problem at source, and make all the subsequent toil with long oars that bit easier.

Assuming a move of 70mm, 4.25m (just under 14ft) oars are about 250g lighter, slightly stiffer, 0.1kg less UHF and a little cheaper. The solid cedar oar would be 2.4kg UHF which I'd say is within range. Solid spruce is 2.5kg UHF.

We only need two inriggers and the work is not huge.

topherdawson
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Re: What can we agree on?

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