Author: Ewan Kennedy

The next steps

Ewan Kennedy Building the boat, Getting Involved, Job lists 0 Comment

Now that the hull is planked we have to complete the tasks in the last jobs list, which will take some time, so there’s no point in my posting weekly lists of things to be done. The main thing is that the work becomes much more interesting and we hope that Sunday afternoons in the cow shed will become a mini visitor attraction for those wanting to become involved, as well as those who are already interested but have not visited yet.

Remember, it’s absolutely not necessary to buy a share to take part in Seil Coastal Rowing, nor to be resident on Seil (for example I’m not). This is a genuine community project open to all who want to take part and there will be lots to do supporting the skiff as well as rowing her.

Turning to practical matters we have to decide a number of things fairly soon.

Nick Bowles has suggested that a nice colour scheme would involve a cream hull with a slate grey sheerplank and a lighter grey interior. Personally I think this would look great and I love the local reference, apart from which there seem to be no other skiffs sporting grey at present.  It also widens our geographical range to include the other slate islands. Looking at the picture of other boats online it seems that lighter hulls work well with the St Ayles skiff profile. Any other suggestions?

We’ve also been thinking about the extent to which we can make minor deviations (improvements?) on Iain Oughtred’s design, while making sure  that we stay within the Class Rules. The following exchange of emails among Ewan Kennedy, Robbie Wightman and Topher Dawson is relevant.

Ewan’s email to Topher and Robbie

“There are a few practical matters that I’d like to run past you ….

It seems that rudder design is uncontrolled and we are free to plan what we want in terms of the size, shape and angle of incidence of the rudder blade.

It also seems that there’s no problem with an open inwhale, which we see in the photos of other boats and would like to adopt.

We’re considering moving the thwart positions a wee bit forward, as we see that some skiffs are squatting especially when they have a heavy cox aboard. I think some teams have done this already.

Finally I’m thinking of introducing a small amount of rocker, possibly reducing the depth of the external keel at the ends by an inch or so from Iain’s construction drawing. It’s difficult to be sure from the photos online, but it looks as if there are some variations already in keel profile.”

Topher’s Reply

“Well done for getting the planking finished, and I look forward to seeing the finished boat. The rudder does seem to be as you say, uncontrolled, and there are many variations on a theme. Slotted gunwales are also OK and we have gone down that route (without reducing weight) for reasons of strength and drainage.

If you move the thwarts my advice would be to keep the number 3 seat centred on the frame, move the stroke seat 2 inches aft, number 2 seat 2 inches forward and the bow seat 4 inches forward, thus increasing the space for each rower by 2 inches and moving the rowers forward, on average, by an inch. We did this on our second boat and so did the Sailing club here.

Although oars are many and varied, a consensus does seem to be forming that the oars are better restrained in some way from floating in or out at the oarlock. My advice which you are well experienced enough to ignore would be to make the cheap oars on the oar tab of the SCRA website, and then using those as a datum make better ones when you know what you want.

I’d be a bit uneasy about introducing rocker or reducing the outboard part of the keel, because of the advantages to speed and turning which this departure from the plans would introduce. I’m aware as I write this that the same could be said of changing the seat spacing or fiddling with the rudder, but somehow the outside of the hull is sacrosanct, and I would not like to see people cutting their outside keels down to reduce drag. As you say this may already be happening and so far we have not done anything about it, but it could get out of hand.

We may have to issue guidance on this, what do you think, Robbie?”

Robbie’s Reply

“Agree absolutely with Topher.  In the measurement rules there is a difference between hulls and fittings (including thwarts).

For Hulls the rule is:

2.1 The hull is to be constructed as faithfully as possible to the St Ayles Skiff plans produced by Mr Iain Oughtred. The hull may be constructed from a kit from the approved kit supplier or may be built entirely from the plans. That to me excludes varying keel shape by introducing rocker.

For fittings the rule states:

4.1 While the plans show how Rudder, Tiller, Oarlocks, Thwarts, and Seats can be constructed, it is open to the builders to innovate and experiment with these fittings.

4.2 Oarlocks must be at the gunwale. Outriggers are not permitted.

Innovation to me includes spacing the thwarts slightly differently, and that has improved the trim of some boats.  IO introduced extra buoyancy in the hull shape after the prototype to try to sort out the fat cox problem, but the boats do still tend to sit rather heavily by the stern. It can be helped a little bit by the fat cox sitting forward to shout in the stroke’s ear, rather than sitting back and relaxing.

Full measurement rules are here:  http://jordanboats.co.uk/JB/StAyles/Building_Measurement_V5.pdf

We need to form a sub committee to review the measurement rules at some point.”

Clearly there are matters to be decided and it will be helpful for the building team to hear from anyone who has something to contribute to the “variables”.

Jobs List for Tonight

Ewan Kennedy Job lists 0 Comment

Sorry about the late posting, but I’ve been away.

Plank 6 is now on, so we can take our pre-made external stem sections off the shelf, dry-fit them and mark them for shaping, also assembly the two strips that will form the external keel, mark them up and glue them together.

There’s also a lot of general cleaning up of glue drips and lots more sanding to be done.

Jobs List for tonight – 26 September

Ewan Kennedy Building the boat, Job lists 0 Comment

Sorry it’s a bit late, here is the programme for tonight’s exciting instalment.

Some fairies came along and sorted out the plank gains, so plank 2 is now ready to hang and we’ll get that done tonight. Plank 3 has  been assembled but as it’s rather cold we’d better leave it to cure before clearing the table to assemble plank 4, which already has its scarfs cut.

Plank 2 port side trial fit
Plank 3 glued up

Plank One is on

Ewan Kennedy Building the boat 4 Comments

Another wet Saturday was put to good use, when the first plank sections went on and three of us got a nice masterclass from Richard Pierce, now returned from his adventures in the States.

Our (well, mainly my) efforts at bevelling the keelson and stems to meet the planks were reviewed and mistakes corrected. I had been over-enthusiastic in the sections between the moulds, producing a slight scalloping. It’s quite easy to do this, as one tends to lift the plane when getting near to the moulds and naturally press harder between them. This can’t happen again on Seil Skiff Number One, as there’s only one keelson per hull, but it’s a warning for when we get to our second ship. Fortunately I hadn’t done anything that couldn’t be smoothed out and Richard soon had things sorted.

At the stems I had gone the other way, being afraid of removing too much material. Richard explained how the planks will naturally take a concave curve at the ends, clearly visible in the picture of the finished job. The natural tendency when planing is to concentrate on the sides of the work piece, so that one produces a convex profile and accordingly a bad joint or, worse, an outward lengthwise bow that will produce a bulge in the plank once it’s on, with a compensating flat in the section behind, as the material for the bulge has to be borrowed from somewhere. While one is always anxious not to remove too much it’s actually a lesser sin than not taking enough off. Wood can’t be compressed, whereas an accidental void can always be filled with thickened epoxy. This may be a reason why traditionally-trained craftsmen don’t always look kindly on garage boat-builders – they spend years being trained to produce a perfect fit, then we come along, mix our chemical mud-pies and end up with a stronger boat.

Richard quickly supplied the required concavity with a few passes of one of his favourite tools, the angle-grinder, minus safety guard but with sandpaper on a soft rubber disk replacing the usual wheel. The same tool also cleaned up the edges of the moulds and sorted the angles on the frames.

These corrections done we found that both sections lay sweetly in place, requiring only light hand pressure to come in to the stems, with edges completely fair. It was then a simple matter to glue up the faces and hang both port and starboard sections, securing them with a mixture of temporary screws and clamps. The remaining planks will be progressively easier, the sections having to cope with less and less twist as we move towards the sheer.

angle grinder in use

first plank trial fit

first plank in place
second plank clamped on, photo by RP

Making Our Skiff’s Oars

Ewan Kennedy Building the boat 1 Comment

I’ve been spending a wet Sunday reading the numerous postings by our skiffie friends on their experiences with different types and sizes of oars. They’re very generous in sharing their ideas but this is also quite confusing as it’s clear that there isn’t universal agreement on anything. The purpose of this post is to start a discussion about what we should provide for our first set of oars, bearing in mind that they will be the first of many.

The starting point is the rule book, which outlaws spoon oars and the use of carbon fibre but leaves us free to choose any length, section and shape of blade. It seems that various lengths of oar have been tried and certain lengths lead to clashes more than others. Some impressive work has been done by Topher Dawson suggesting an ideal length of eleven feet, although some teams row successfully with much longer oars. He also recommends rectangular section oars, which are stronger in engineering terms than round ones, although they can’t be feathered. The latter doesn’t seem to bother existing skiffies. Finally he recommends the use of the cheapest whitewood, easily available in a 38mm x 89mm section and adequate length. He’s provided a sketch incorporating these points and I’ve modified it a little, mainly by suggesting the addition of softwood blocks to give a little weight at the inboard end, which I think could be beneficial (some add lead to  thehandles to achieve this). You will see that the 89mm dimension is used fore and aft, where it’s needed. There are thin hardwood strips on three faces to cope with chafe against the kabes.

All comments are welcome but unless anyone comes up with something better I suspect our Wednesday regulars will soon start making our first set to this pattern.

Plan for September and Job List for the 5th

Ewan Kennedy Job lists 0 Comment

We have now completed all the tasks set out for the month of August, including everything in the last job list. As a result we have the complete skeleton for our new ship, all glued up and fixed to the floor. The task for September is to assemble and hang the planks, of which there are six on each side, then add the external stem sections and outer keel, all already made apart from final shaping.

This Wednesday we have the following to do.

Set up the base for scarfing the plank sections together and make sure it’s secure and level. The blockboard for this is already in position.

Assemble plank 1, port and starboard sections.

Bevel the keelson and inner stems to fit plank 1.

Left over from before – Clean up and sand the wee end pieces for the frame sections, that will go into the hull later.

Job list for 29 August

Ewan Kennedy Job lists 0 Comment

During the week the keelson and stems went up a hill to visit the wizard woodcutter, who trued up the keelson and reduced it to its finished size of four inches, then thicknessed the stem sections, so we’ve now got a complete kit of parts for the hull.

Meantime the fairies went to the shed and set up the moulds. On Wednesday we can:-

Finish the four frames, by giving them a nice radiused edge where they will be on the inside of the boat, then completing the sanding already started.

Fit parcel tape to all mould edges and surfaces that will be in contact with the boat.

Screw the frames to their respective moulds.

Cut the stems to fit the keelson.

Place the keelson in position.

Glue the keelson to the stems and frames.

Fit extension pieces from the stems to the floor and glue them in place.

If we get all this done I’ll be astonished. The next step is bevelling the surfaces that will take plank one.

Job List for 22 August

Ewan Kennedy Job lists 0 Comment

We’ve had a trial fit of the building frame on the caterpillar. The good news is that everything goes together very nicely. This means that we’re at the end of phase one of our build and can move on to setting everything up for serious boat-building.

Building setup bow view
Building setup bow view

General Clean-up

We should now have our first big clean-up of the building space, as we’ve finished making our kit of parts for the main hull and won’t have to make any new pieces for the next month.

We should gather up all scrap plywood, saving the bigger bits of marine ply and scrapping the cheaper stuff that the moulds were made from.

Building setup stern view
Building setup stern view

Finish the Frames

The four frame pieces have all now cured and can be unclamped.

The inside faces and the flat fronts and backs will all be visible inside the completed boat, so will need to be sanded to remove the runs of epoxy that have squeezed out. The sharp edges should be nicely radiused.

Finish the Building Moulds

The mould pieces are all looking good and need to be cleated together using fish-plates made from scrap ply on both sides of the upper sections and the cross-spalls from CLS timber, which Ray has been making.

The online instructions for the set-up are available here:-

http://scottishcoastalrowing.org/files/2010/12/Ch-5-Mounting-the-Moulds.pdf.

We’ll have a few paper copies in the shed for reference as the evening proceeds.

The instructions are very clear and easy to follow, so I won’t try to improve on them. They are written with the traditional building ladder set-up in mind, but I don’t think any changes are needed for our closed caterpillar set-up.

Note that Mould 1, at the bow end, will be screwed onto the outside face of the wee open two foot box furthest from the door. It’s been left clamped in position.

Note also that the cross-spalls go on the AFT faces of moulds 2 to 5 inclusive and the FORWARD faces of moulds 6 to 10 inclusive. This is essential to ensure that everything can be taken apart once the planking is complete.

By contrast the frames will go on the FORWARD faces of moulds 2 and 4 and the AFT faces of moulds 6 and 8. This is so the edges can be bevelled slightly to give a close fit to the planks.

There is a box of long screws to secure the cross-spalls to the top of the caterpillar, one screw on each side of each mould.