Monthly Archives: September 2014

Rocker and Stability

Boat design is all about compromise. Ideally, the canoeist needs a dynamic boat which changes to suit the water conditions and the paddler’s skill and experience.

This is no better illustrated than on the Devizes to Westminster canoe race where the requirement is:

  1. A fast, narrow (and comfortable) boat for the first 14 miles.
  2. A lightweight boat which is easy to get in and out for all the portages to Reading.
  3. A more stable boat for the long stretches on the Thames.
  4. A rock-solid stable boat for the tideway.

There are too many design ideas which are in conflict and mutually exclusive. It’s the responsibility of the designer to decide where the compromises should be. It is up to the user (purchaser) to select the design which best suits their purposes, but no boat will be perfect.

Personally, I’m looking for a C2 which will be fast, light, comfortable, ICF compliant, stable, affordable and looks great.

So, onward with testing.

In order to improve the stability, I forced open the sides of the boat to increase the width

Sides splayed out

Sides splayed out

This inevitably caused the ends to rise slightly and increase the rocker. However, the changes I’d made to the hull kept this to a minimum.

Increased rocker

Increased rocker

Top view

Top view

What it also meant was that the amount of freeboard between the surface of the water and the top of the gunwales was only about 8 cms (3 inches in “old money”). However, it turned out that this didn’t matter because the stability was massively increased.

C2 - forth trial

C2 – forth trial

With the increase in stability came more assertive and confident paddle strokes. It was easier to keep the boat straight, although John’s left stroke is far more powerful than paddling on the right. This meant I had to work hard to avoid the bank, but the further we paddled, the better I was at anticipating this behaviour rather than reacting to it.

I was somewhat surprised with the vast improvement in performance simply by splaying out the sides, and our speed increased significantly. This can be seen on the YouTube video:

This boat has served its purpose and it will be chopped up and discarded. I am clear about the amount of rocker and the seat positions. I need to make the boat narrow to be fast, but wide enough to be stable. It would also be better to raise the height of the seats for comfort and more efficient paddling (so, more stability then!).

These criteria will be input to the CAD design and the Naval Architect who translates my ideas into data and one day, into a boat.

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Pangbourne Haslar

Paddled The Darkness in the Pangbourne Haslar yesterday. Thirty seven boats on the start of the Div 7 race.

Gathering before the start.

Gathering before the start.


I decided to start out of the way on the left hand side. My start was better than Longridge but the kayaks quickly accelerated away.
The start.

The start.


I managed to keep about 15 boats at bay before the turn, but as I struggled to turn the boat, 3 or 4 zipped inside and on the outside of me.
The turn.

The turn.


I chased them all to the finish, getting the better of a couple, but I was disappointed that two pipped me by 6 and 10 seconds. I finished in 39 minutes 16 seconds, 4 minutes behind the winner and 28th position out of 37 starters.

I mounted the GoPro on the rear of the boat before the start. Some excerpts can be seen on YouTube:

An excellent and well organised event, good fun too.

The Sharks – canoe time trial

There’s a canoe club; The Sharks (http://www.thesharks.org.uk/). “The Sharks organise a monthly canoe marafun racing league on the second Tuesday of the month (April – September) and on the second Sunday of the month (October – March) at Harefield to encourage participation. The league and the races are designed for paddlers of all abilities.”

It’s a time trial format at various distances, the longest being 6.4 miles. This involves 5 portages including the one at the far turn meaning that there isn’t a “dead turn” at the half way point.

It’s good fun and an excellent way to measure performance. There are medals at the end of the series for the fastest boats in each class, and a shield for the club with the most points. Points are based on number of boats from each club and not performance.

The course starts and finishes below the bridge at Coppermill Lock, opposite the Coy Carp (PUB!!). It uses a rather pleasant stretch of the Grand Union canal which has a bit of current on it. There’s ample parking at the PUB, good access to the water and good organisation. (Did I mention there’s a PUB?)

Anyway, I rocked up with The Darkness last week and finished in just under 62 minutes to claim the C1 fastest time of the year.

So, this is the view from the start. Paddle past the mill stream and under the bridge.

Start and finish "line"

Start and finish “line”


The first portage is an easy out, run down under the bridge and put back in.
Out on the right.

Out on the right.


The second portage is equally easy.
Out on the right again.

Out on the right again.


The turn is fun. Paddle under the bridge, out on the right, leg-it over the bridge and put back in at the camera position.
Up and over.

Up and over.


Thoroughly enjoyable and worth checking out.

C2 conversion – re-positioned seats.

Got a call from John this morning, even though he’s on nights, he offered to help test the new seat arrangement on the C2 conversion, top bloke! John has completed the DW eleven times. Three senior K2s (3rd, 6th, 2nd) and nine K1s, the best time being 17 hrs 23 mins. A kayak paddler, he has had next to no experience of the dark side.

Anyway, I set the GoPro up on what’s left of the rear deck and we put in at Pewsey wharf.

First impression was a significant improvement in being able to control the direction. The main issue was the lack of stability, mainly due to the rear footrest not being properly attached to the gunwales. However, our confidence grew as we progressed and I reckon John could make it on the dark side.

Repositioned seating

Repositioned seating


The boat went better than I had expected, which can be seen on YouTube:

The main conclusions are:

1. Need to fix the rear footrest to the gunwale.
2. The position of the rear paddler towards the back of the boat does help steering.
3. The production boat must be significantly wider and more stable. This will help with more aggressive steering strokes.
4. The boat will be quick, but how would it compare to the Wenonah ICF?
5. More time is needed on the water.

A racing C2 this sort of shape and size looks a promising proposition.

Longridge Haslar – a turn too far

I paddled the Longridge Haslar last weekend. The venue has some great facilities, but parking remains a challenge. I parked under the motorway bridge, ready for a fast exit!

Simples!

Simples!


Organisation was good, but many of the Div 7 – 9 paddlers (myself included) thought that the race course was unnecessarily complicated. It involved four 180 degree turns in four miles. I had a word with the course designer and he said he wanted it to be like an international event with lots of action at the turn points.

Anyway, 26 kayaks lined up for the Div 7 race, plus me in a C1. At the start I floundered a bit in the “washing machine” as the faster K1s took off. Once I’d found my rhythm, I managed to pass three boats before the first turn, only to see them nip inside me as I struggled to bring The Darkness around.

I passed five boats up to the second turn and once again, two took the inside line. This pattern was repeated to the finish and I eventually finished in 19thposition, being beaten by the two boats by a margin of 12 seconds. If the course hadn’t so many turns, I could have improved on my position.

I can’t blame the course though, it was designed for kayaks (with rudders) and they are hardly likely to make allowances for a single C1.

I stayed to take some pictures of the later races which I posted on Face Book.

Div 3 racers

Div 3 racers


Looking forward to Pangbourne.