Yet another rowing boat design

[John Perry]

A few months ago I started building a rowing boat of my own design. I now have all the plywood cut out by a fairly local company using a water jet cutting machine, I have only good things to say about that process. I am about two thirds through making all the small detachable parts of the boat, i.e. the parts for the sliding seat and folding outriggers, rudder, footrest etc. I will need to clear space in my garage (i.e. take junk to the tip) before I can start to assemble the actual hull.

If there is interest I will post some 'artists impressions' of the finished boat, but I thought it might be fun to initially post just my 'statement of design intent' then see if the experts on this forum can suggest plans that I could have brought or downloaded rather than drawing my own. Just thought it would be interesting to see if such plans bear any resemblance to what I have produced!

So my statement of design intent is as below. Incidentally, I have written this after completing the design work - I do find it's so much easier that way round!


* A lightweight rowing boat for either one person rowing on their own or one person rowing with a passenger.

* To be suitable for inland waterways and for estuary/coastal rowing in favourable conditions.

* To be suitable for home building with epoxy and plywood, any metal parts being made using small machine tools (lath and mill).

* To have an overal length not more than about 4.5m to allow roof rack transport and reasonble storage/building space requirements.

* To include on-board dry storage space for camping equipment for two persons camping onshore.

* To include a sliding rowing seat that can be locked in position for fixed seat rowing. There is also provision for future addition of a sliding row lock system in place of the sliding seat (although the sliding rowlock system will not be suitable for use with a passenger on board)

* To include generously sized bouyancy tanks.

* To include outriggers for the rowlocks (oar gates) that can be easily folded in to enter a lock or to come alongside a quay and that can be easily removed for roof rack transport. Oars to remain supported in rowlocks when rowlocks folded inwards.

* To include a steering system for a passenger to steer the boat or to act as a skeg with fixed rudder angle when one person is rowing alone. Rudder blade to be easily lowered/lifted by either the person rowing or a passenger. Provision for either a small rudder blade for open water rowing or a larger blade for good manoeuvrability when rowing with a passenger on inland waterways.

* To include a launching trolley that can be dismantled and stowed on board the boat after launching. The launching trolley also useable as a lightweight trailer for towing the boat with a pedal cycle.

[Ben Fuller]

Don't know about experts, lots of people here just muddling along.

As far as the basic boat shape goes there are a bunch of designs out there, but what I think you are doing is decking and bulkheading like a sea kayak for storage which is pretty unique, and building your own folding rigger and slide kit will be really interesting. I guess the downside will be additional weight when it comes to getting it on the roof. The Finnish guys just put in firmly attached net "decks" in the ends of their boats under which drybags can be securely stowed. I've done the same in an oar and sail boat. Nice thing about that is that the camping gear bags then can get carried to the spot without having to fit through hatch holes.

I was once part of a crew that built a fixed seat triple, with a bath tub in the center long enough for three rowers. Side bulkheads had cleats for seat supports and stretchers. We had folding metal outriggers. I've lost track of the boat but I believe it has been converted to a double slider. Two could roof rack it but at over 7m it wasn't fun.

How you work out a launching trolley will also be of interest. Most designs are some flavor of strap on and have no long beam. What I have seen is a fabricated bit on the bow of a boat that gets it hooked onto a bicycle allowing the use of a folding strap on.

Something to ruminate about on this Christmas Eve.

[James McMullen]

I'm interested to see what you've come up with. Colin Angus has an interesting rowing cruiser design available that sounds like it might be in the ballpark of what you're suggesting. I wonder how close your design is to this?

http://www.rowcruiser.com/RowCruiser...owCruiser.html

[rgthom]

The intent is interesting, would really like to see the sketches of how you are going to implement these ideas. With room for two, buoyancy compartments and storage it sounds bigger than what I would like for roof rack transport. How much do you think it will weigh?

Rick

[Ben Fuller]

Hassle with the rowing cruiser types is that you need space for bodies. The simple bathtub style that we did for the triple made roof racking ( on a long lumber rack) pretty easy as the cockpit coaming was nice and flat and designed to take weight. Decks were as well so if the rack was longer than the cockpit boat could go in decks. I think we found that upside down made life easier on the racks. Problem with our boat was weight; at around 25' long, about 3' wide, structureless chine S&G it was all two people could do to rack it.

[rgthom]

I think I saw riggers once that pivot around a vertical axis, so a bang from the lock wall would tend to push them to the retracted position. I want to try that on my next boat, maybe held in the out position just by a line. I had a set that folded in around a horizontal axis and held the oars captive.

[John Perry]

I'm interested to see what you've come up with. Colin Angus has an interesting rowing cruiser design available that sounds like it might be in the ballpark of what you're suggesting. I wonder how close your design is to this?

http://www.rowcruiser.com/RowCruiser...owCruiser.html

James, that is an interesting design, and not one that I was previously aware of. It is a longer and heavier boat than I am building so probably not so suitable for roof rack transport, indeed the designer agrees that it is too big for a roof rack although there is a picture of the part built hull being carried on a roof rack.

I see that when the Rowcruiser is carrying a passenger, the passenger sits forward of the rower and looks ahead. That is an arrangement that I very nearly adopted for our boat, but in the end I went with the passenger sitting aft and facing the rower since it just seemed more sociable that way round. On the other hand, a passenger forward would get a clear view for steering on twisty rivers and the passenger's legs could fit under a foredeck. Another advantage of having the passenger forward is that adding the passenger will tend to pitch the boat down by the bow and with a transom stern this is preferable to pitching down by the stern since transom immersion is best avoided or at least minimised. With my design I have needed two positions for the rowlock outriggers, these spaced well appart, to cater for rowing with and without the weight of a passenger aft whilst avoiding transom immersion.

The row cruiser has a small cabin which again is something I considered but if we had a cabin we would want it to be for two persons, not one as on the Rowcruiser. I think it would be really hard to fit a cabin for two on a boat of the length I feel we can easily transport and store when not in use. A long boat tent with the two persons lying end to end was a possibility that I considered since Josephine was keen to have on board overnight accomodation but in the end I felt that this would not really be practical in such a small boat. So, if we use our boat for river camping trips we will have to take a small tent and camp on the river bank, perhaps fine in your part of the world but not so good in our part of the world where river banks tend to be jealously gaurded private property.

I note that in some of the photos of the Rowcruiser with one person rowing there is some length of forefoot clear of the water which does not seem ideal, but maybe it is because the boat is accelerating, or pitching with the movement of the rower. Or maybe the Rowcruiser does need either the weight of a passenger forward or a load of cruising equipment up forward to maintain pitch trim.

I think the Rowcruiser would be a very nice design for one person on their own who wants to go cruising with a small cabin for overnight accommodation but not quite what we want since we already have a 'sail and oar' boat with a good boat tent that sleeps two in comfort.

<snip>The Finnish guys just put in firmly attached net "decks" in the ends of their boats under which drybags can be securely stowed. I've done the same in an oar and sail boat. Nice thing about that is that the camping gear bags then can get carried to the spot without having to fit through hatch holes.<snip>

How you work out a launching trolley will also be of interest. Most designs are some flavor of strap on and have no long beam. What I have seen is a fabricated bit on the bow of a boat that gets it hooked onto a bicycle allowing the use of a folding strap on.

I am proposing an open 'cargo hold', for bulky items such as the launching trolley, plus stowage through plastic screw down hatches for things that need to be kept dry, such as sleeping bags. The open hold could be covered with a waterproof canvas cover.

Yes, I have nearly finished making a strap on style launching trolley for the boat. It comes into two pieces for stowage on the boat and has quite large pneumatic tyres for rough beaches. I am not sure whether we will actually tow the boat with a pedal cycle but Josephine does not drive and she does have a folding Brompton cycle. So if she wants to go rowing on her own I am thinking of a little tow bar that fits to the bow with a couple of wing nuts, then maybe the Brompton could fold up and go in the boat once its afloat. We will just have to see whether all that is worth the trouble.

I think I saw riggers once that pivot around a vertical axis, so a bang from the lock wall would tend to push them to the retracted position. I want to try that on my next boat, maybe held in the out position just by a line. I had a set that folded in around a horizontal axis and held the oars captive.

Yes, that's just what I have made, but with a hinged strut that snaps into a fitting on the side deck rather than a line to hold them out. I would like the oars to stay in the rowlocks when the outriggers are folded in, which is possible with a vertical folding axis, but it sounds like the ones you had somehow managed that with a horizontal axis. I would have thought that with a horrizontal axis, when the outriggers are folded in they would obstruct the central part of the boat quite a lot, or alternatively would stick straight up in the air.

The intent is interesting, would really like to see the sketches of how you are going to implement these ideas. With room for two, buoyancy compartments and storage it sounds bigger than what I would like for roof rack transport. How much do you think it will weigh?

Rick

By design, it will weigh 40kgs (88lbs). That's with oars and all detachable parts necessary to row the boat but not including crew weight, launching trolley, provisions or camping equipment. I have a two bar ladder rack type of roof rack and I propose to make an extension to temporarily extend the rear bar out beyond the side of the car. Lift one end of the boat onto that then sea saw it into a central position on both bars. I propose to make two rails that can be bolted to the side decks of the boat running fore and aft, then when the boat is upside down on the roof rack these rails will protect the boat and spread the load.

Wish you all a happy Christmas everyone. We are about to go for a walk from our village along the coastal cliff path. its remarkably warm weather for the time of year where we are but there is a gale blowing straight in from the Atlantic - wouldn't like to be out in a small rowing boat!

[John Perry]

Above is an 'artist's impression' of the rowing boat described above.



This is the boat configured for a rower with a passenger sitting aft



and this is the boat configured for a single rower and no passenger. There is quite a big difference in the fore and aft location of the oarlocks, this is to balance the boat hydrostatically in the two configurations (according to my computer!).



This is the current sliding seat viewed from the underside. The wheels have stainless steel ballraces and run on metal rails - there are two plain wheels on one diagonal and two grooved wheels on the other diagonal. I am now starting to dry assemble the hull prior to fixing it all together with epoxy fillets and glass so I have been able to run the seat to and fro on the rails - it runs very freely but I have to say the metal wheels on the metal rail seem a bit noisy - perhaps I should make plastic wheels. Or maybe the whole thing is a bit over-engineered and I could make a simpler and lighter version later on.

Incidentally, I have recently acquired the Japanese rasp tool showed in the last picture and I can say that it is proving to be a wonderful tool for a wood bodger such as myself.

I have no experience of this style of rowing boat so there is a lot of guesswork in the design and I would welcome constructive advice, although perhaps I should have asked for it at an earlier stage - It is still possible to alter parts such as the rowing seat, outriggers etc. but significant changes to the hull structure would be more difficult at this stage.

[Peerie Maa]

This is the boat configured for a rower with a passenger sitting aft

That might be a bit unnerving for the passenger.

I'd spread the seats out further if it were me.

[Thorne]

That might be a bit unnerving for the passenger.
I'd spread the seats out further if it were me.

As the kids say, "Word".

[peterAustralia]

I quite like it. What are the dimensions for that boat. I have just come back from a four day rowing trip, and my biggest bugbear is the wind. I need freeboard to keep out the water, yet freeboard creates windage. If however the fore and aft decks were sealed over and were cargo/buoyancy compartments, then freeboard could be lower. Add removable outriggers for more speed. Keep the central 6.5ft open for a rowing position with a removable padded seat, then remove the seat and you have a sleeping position, a couple fiberglass hoops to support some canvas to keep the rain and wind out.

[rgthom]

I love it, very much the way my boat is set up except yours is narrower, lighter and faster. Adding to the chorus - the passenger needs more room. She has nowhere for her feet, and unless you want a kiss before every stroke ... The open cockpit on my boat is 9 feet, that is comfortable for passenger aft and slide seat rower at bow. I would move the passenger seat all the way back, maybe using the sides for your storage instead.

Metal wheels on metal rails - that will be noisy for sure. My seat is copied and modified from the Gig Harbor slide seat system, using skateboard (or rollerblade) poly wheels. It uses 8 wheels, but only needs a simple flat track. Here is the seat:



On the track:


This has seen thousands of saltwater miles so far, is quiet and maintenance free. You would not even need separate rails by the look of your drawing.

Here is some Gig Harbor info on their seat: http://www.ghboats.com/frequently-as...ing-seats-faq/

Edit: The grey rafting seat is not required, but consider something more comfortable than the usual hard racing seat for day-long rows.

Edit again: Picture showing close up of Gig Harbor seat wheels.



I just want to stress that a soft wheel seat should be easy to fit in your straight sided seat opening, and I'm sure you will find it far more pleasant than metal on metal.

-Rick

[John Perry]

Thanks for all your helpful comments - I should have sought your advice a bit earlier on! I will be away for a few days but when I get back I will definitely set up a mock up of the seating arrangement, just with low stools or suchlke, to get an idea of how bad the seating problem is. I actually did that before drawing the boat but at that time I assumed that the rowers hands would not come further aft than his/her feet. That just shows how little I know about this kind of rowing. (I say his/her - I am hoping that I will sometimes be the passenger and Josephine will be rowing) The difficulty is that I am trying to get two people and some camping equipment end to end in a rowing boat that is shorter than most experienced rowers would consider to be desirable even for just a single rower. Some compromise may be necessary but it is clearly unacceptable for the oar handles to be ramming the passenger in the face.

If I do need to move the passenger seat aft to make more space, that probably means getting another sheet of plywood waterjet cut, no big problem although the lead time for the waterjet cutting might hold up the project a bit.

Rick - your boat looks terrific!

John

[John Perry]

We are back at base now and this evening we did a quick check on the geometry of the proposed, and now partly built, rowboat. I do appreciate the concern about the distance, or rather lack of distance, between the passenger seat and the rowing position. However, we have just this evening set up a crude mock up of the geometry using blocks of wood to sit on. I dont think the current design is as bad as it may look at first sight. The passenger is on a seat low in the hull, using an aft sloping bulkhead as a backrest. The passengers feet are forward of the rowers feet, i.e. the passengers legs overlap with the rowers legs and the width of the central 'trench' in the boat is enough for this to be possible. The distance from the line of intersection of the seat and the bulkhead (i.e. the back corner of the seat he/she is sitting on) is about 860mm aft of the rowers heels. When the rower is in the most far aft position he is likely to be on the sliding seat his hands will be perhaps 300mm aft of his heels, this being based on photographs such as that posted above by Peeri Maa - AKA Nick. The passengers nose is perhaps 200mm forward of the back corner of the seat, the seat back being sloped to the rear, not vertical. That leaves 360mm measured in the fore and aft direction between the rowers hands and the passenger's nose - doesn't sound like a lot but enough that the passenger is not going to get the rowers hands punching in the face. But actually it is much better than that since at that part of the rowing cycle the rowers hands are spread wide apart, as in the pic that Nick posted above, and his hands are moving outwards as well as aft so they are not moving directly towards the passenger's face and I dont think they will be all that intimidating for the passenger. Also the rower's face is a few hundred mm forward of his hands, so there is something like 800mm minimum separation between the face of the passenger and the face of the rower - no chance of a kiss on every stroke!

Happens that I was at the London boat show the other day and got chatting to some young ladies from a team that are planning an attempt on the women's transatlantic rowing record. They were proudly showing me the features of their boat which is intended to carry four, with up to three rowing at any one time, the others resting. I noted that they have rowing seats that each run on eight rollers much like the seat on Rick's boat. Altogether, that's 8x3 = 24 rollers, seems a lot, but I suppose that doesnt really matter. These seats do run smooth and quiet, but one of the reasons for having the type of roller arrangement that I have made is that it should work with a sliding rigger as well as a sliding seat and I thought I might like to try that at some stage. For a sliding rigger I think you need some of the rollers to hold the rigger down, for a sliding seat all the rollers only need to support upwards. If I dont use the sliding rigger maybe I could make a slightly simpler sliding seat arrangement.

John

[rgthom]

It sounds like you have thought it through and the geometry is do-able. You guys have so much dinghy cruising experience together I'm sure you know what works.

My passenger likes plenty of room (and sun shade and a cooler and a snack table). This is not a car-toppable boat, though:

[John Perry]

Nice photo Rick, what kind of a boat is it, or did you just make it up as I have done? As you say, it is a larger and heavier boat than I am proposing, but it looks elegant and I expect it is comfortable, you might even have room for two to sleep on board overnight with a cockpit tent. I see you can have a picnic on the boat, we would need to go ashore for that. You have the beam not to need outriggers for the rowlocks which is a useful simplification.
John

[keyhavenpotterer]

Think that's a Welsford Walkabout http://www.jwboatdesigns.co.nz/plans/walkabout/

same as this one with it's rig fitted

[rgthom]

Yes, Walkabout. I don't have the guts to design my own like you guys...

[John Perry]

After unpacking the pre-cut pieces of plywood as water-jet cut by Luffman Engineering at Tiverton, I made little progress with Josephine's row boat until a few days ago - house DIY and other interests seem to have taken over from boat building this past winter. However, a few days ago I cleared enough space in our garage to start fitting some of the plywood parts together - its still a 'flat pack' but now the sections of the hull panels are joined to make panels the full length of the boat - very flopitty at this stage.
https://photos.google.com/share/AF1Q...tuRXM3REo1TXpR

So far I am pleased with the way the parts are fitting together but the real test will come when I start assembling the main panels into a hull, maybe later this week. The finger style scarf joints seem to work well, see photo. Although the tapered overlap style of scarf joint is not all that difficult to make, these finger joints are even easier and I suspect equally strong so if you are using computer controlled cutting you might as well include them when you have the parts cut. I set up a long temporary work bench from some scrap pieces of chipboard then laid out the panels with a piece of polythene sheet under each joint, then wetted out a small piece of light glass cloth over each joint, covered the joints with more pieces of polythene then clamped flat blocks of wood on top to compress the whole sandwich. I know from a past experience that you need to use thick polythene for this, thin polythene wrinkles when it comes into contact with the epoxy. Actually, for the first panel I just used the weight of some bricks instead of clamps but the clamps worked better, or maybe I could have done with heavier bricks. I had the fingers cut with a small gap, I think it was 0.5mm (20 thou) for the epoxy to permeate, I dont know whether this is really necessary though. Still amazes me that a high pressure jet of water can cut with this accuracy. For each long panel I had small holes cut near each end of each sub panel, these holes lining up when the sub-panels are correctly positioned. This allowed the panels to be aligned on the bench by lining up these holes beneath a tight (purple) string (see photo below) - I would not rely on a tight string for vertical alignment since there must always be some sag in the string but its fine for horizontal alignment.

https://photos.google.com/share/AF1Q...tuRXM3REo1TXpR
When we lived near St Albans our house was next door to some hospital buildings that the NHS no longer needed and when these buildings were demolished, needless to say to clear land for more housing, I noticed that rough shelving in a store building was made from approximately 18foot lengths of soft wood that was straight grained and totally free of knots. Also, when the hospital laboratory benches were demolished long lengths of teak something like 2 foot wide and more than an inch thick were discarded. I did manage to get hold of just a few pieces of this timber although most of it was carted away by a guy with a pickup truck who said that he needed it for his wood burning stove! Anyway, I have been storing this timber for years so the row boat seemed a good use for the softwood, hence I have been using a long straight cutter in my router bench to thickness it to the small sections needed for this suposedly light weight boat. Three long strips have been cut and epoxy glued onto the 3mm plywood panel what will be the floor of the boat so as to take the weight of a person. Two more long strips have been cut make what I think are called deck carlins - these support the inner edge of the side decks. Regarding the deck carlins, this afternoon I routered the initially 40 x 12 mm section into a channel section that should have almost the same stiffness vertically but be a bit lighter. Before routering each deck carlin weighed about 850gms, after it weighed about 600gms - well it all helps surely. In the same vein, Josephine has brought us some titanium cutlery with lightening holes in it - rather nice cutlery actually and not all that expensive.
https://lh3.googleusercontent.com/D8...w=w800-h630-no
This picture shows my router table which also doubles as a general purpose workbench with a removable plywood top surface. The router parts were taken from a cheap but rather nasty ready made router table that I got from the internet - I still could do with making a new 'fence' since the one supplied, as in the photo, is only straight and vertical when I pack shims under it and in any case its too short for the bench. Just visible below the top of the bench is the handwheel that raises and lowers the router cutter, also the emergency stop button for the router motor. Note that the top of the bench is overhanging which is very handy for clamping items to it. Also, the bench has wheels at one end so that I can wheel it from my workshop (originally the dining room) out into the garden when I want to work on long items or when I want to make a lot of mess. Enough writing for now!

[John Perry]

An update on progress on the rowing boat. The parts that I showed as a 'flat pack' in a previous post are now all dry assembled into a three dimensional form that I think somewhat resembles a boat. The finger joints between panels are epoxy glued but otherwise there are only copper wire ties plus a few temporary woodscrews holding it together at this stage. The assembly of the hull to this point has not actually taken many hours, although it has been spread out over several months. I have found it a satisfying process, seeing the shape of the boat develop from the flat panels. It is perhaps the most enjoyable part of boat building, so I have been feeling no desire to rush it which is perhaps why it has taken a while.

The assembly was done without any jig or 'strong back', relying entirely on the shapes of the panels to produce the shape of the boat. The other day we took the boat outside to weigh it in its current form and took a pic or two - see above. We weighed it with rather rickety old bathroom scales, modern electronic scales could be more accurate. It was hard to balance such a long object (15 foot LOA) on the scales, and we had to raise the boat off the scales on blocks so as to read the dial with a small mirror. As best I can tell the hull weighs about 23kg. This is with pretty well all the plywood given one generous epoxy coat on the internal surfaces but without any glass reinforcement or epoxy fillets at the joints between plywood panels, also without the external sheathing of light glass cloth and epoxy and without any of the metal fittings or the paint. The predicted final weight of the boat is 40kgs, this includes the oars and other removable parts such as seats, seat cushions, the folding outriggers etc. I guess that at this stage I am probably about on target to achieve that final weight, will be interesting to see and useful information if I ever make any more boats. (where would I put them though!).

One question, when pre-coating the plywood prior to assembly I left a strip of bare plywood along the edges which are later going to be joined with strips of biaxial glass and/or epoxy fillets. My thinking at the time was that the glass/epoxy would be better applied to bare wood than to previous epoxy that has already fully hardened. Does this make sense ? - Perhaps it makes no odds really.

Once this boat is finished I will probably place the .dxf files for the parts somewhere on the internet so that if anyone fancies making a copy they can find themselves a cutting firm to make a kit, or load the files into a free dxf viewer then cut the parts out manually. However, I won't do that until we have the boat on the water and checked for any problems. I wouldn't want to be responsible for lots of boats that all float the wrong way up!

I don't think I will do any more boat building this summer since we plan to go away sailing abroad very soon,indeed by our original plan we should already be sailing on the Baltic Sea.

[John Perry]

The rowing boat discussed in this thread is now completed and has made its maiden voyage which was an approximately 60 mile camping trip down the river Thames in UK. The trip was made in company with a fleet of 14 small boats, all but two of them home built and all but two of them without engines. Some used paddles, some oars, and two boats were fitted with Hobie Mirrage drives. No one was racing so I could not say which method of propulsion was fastest. We started near the source of the river, just downstream from Lechlade in Gloucestershire and completed the trip a few days later by arriving at the Beale Park boatshow which is held annually on and around a lake that connects into the river near Pangbourne. We entered our boat in the amateur boat building awards competition which is held annually at the Beale Park boat show and won the prize for most innovative boat. This year there were only four entries, three entries having cancelled because the boats were not finnished on time and since there are four prizes each year all entries this year received a prize, which is a nice result.

Just to check that the boat actually floated the right way up we did launch it briefly on our local water a few days before starting the Thames row - the picture shows it on the slipway at Mountbatten a few minutes before floating for the first time. I weighed the finished boat with a good scales and found it weighs 43.5kg without the carbon fibre oars (which add just a bit under another 3kg) The weight predicted by the computer was 41 kgs, the small difference is probably mainly a bit of extra epoxy resin/filler here and there. The boat is built from good quality 3mm marine plywood and is externally sheathed with glass fiber and epoxy resin.

Soon after setting off on the Thames trip we found that the rudder was too small to control the boat properly on the twisty upper reaches of the river. This was not a complete surprise. After I had cut out the rudder blade from a piece of old oak floor board I realised that it was weakened by a large knot that had been filled with some kind of wood colored filler and feeling too lazy to start again with a new piece of wood I just cut off the end of the blade. My thought was that if it did prove adequate that way it would be a bit less drag in the water than the blade as originally intended. However, after a few hours of frustration, colliding with overhanging branches on the river, we found a discarded bit of plank by the riverside and tied that onto the blade with string which allowed us to complete the trip although I think we had some drag from that plank. Later on we tried the boat both with a passenger on board and rowing without a passenger and discovered that the small rudder blade is adequate for solo rowing. It is only when the boat is loaded with a passenger as well as the rower that a larger blade is needed so I am thinking about making a streamlined fibreglass sleeve that when necessary would enlarge the existing small blade by sliding over it and locking in place with a small pin or suchlike.

Apart from the difficulty with the rudder blade the boat seemed to perform well, although neither myself nor Josephine know much about rowing to judge that. We did briefly lend it to an experienced rower who told us that he thought it was set up about right with regard to rowlock and foot plate position and he thought it was a fast boat considering that it is only a bit over 15 foot long and has a relatively stable hull shape. He did say that he would prefer a boat that could be rowed without needing a rudder. I expect the reason the boat needs a rudder is because the transom stern easily slips slideways over the water whereas a canoe stern or a 'whitehall' style stern would grip the water and give better directional stability but would also inhibit making a really tight turn should you need to do that.

We found that the boat has adequate storage space to carry food and camping equipment for a trip lasting a few days. The open cargo space behind the passenger seat holds our tent, a few dry bags and a plastic box for food. A second plastic box with stove, mugs/plates and more food sits down in the bottom of the boat under the sliding seat. Sleeping bags are just stuffed through the round plastic hatch in the foreward bouyancy tank.

You see from the picture that the boat has a pair of wheels for moving it around on shore. These have proved to be very handy and so far have been used in preference to the more conventional trolley that I also made for the boat. These are wheelchair wheels with quick release axles that can be clipped to the boat in a matter of seconds. The bearings for these wheels are not waterproof so when launching the boat we wheel it into a position where the wheels are just clear of the water then take off the wheels and lift the boat from the bow so that the stern floats, then push it out onto the water. The transom stern helps with this since it floats the stern of the boat in little depth of water. I have made a detachable towbar that connects the boat to the seat pillar of a Brompton folding bicycle. I have tried that for a short distance on the quiet road outside our house, not sure about it for busier roads!

The outriggers for the rowlocks, which I think are called 'gates' since they are the type that lock over the oars, are designed so that they can swing inwards when entering locks or coming alongside the river bank. These outrigers clip into place over the side decks and do not obstruct the interior of the boat when retracted. The oars remain in the gates and lie fore and aft above the side decks when the outriggers are retracted. This arrangement works well and is possibly the reason we won a prize for most innovative boat. Throughout the Thames trip I dont think we ever bothered to take the oars out of the gates, even when lifting the boat onto the river bank for the night.

A few of you commented on my drawings saying that the rower and passenger are seated too close to each other. The feedback is appreciated and it was a point worth checking but I can report that in practice this is not a problem - there is plenty of space betweeen the oar handles and the passenger even when the sliding seat is at the aft end of the stroke.

[cstevens]

Nicely done! I missed this the first time around but I like the finished boat very much. What, if I may ask, are the cut-outs in the bow? Handles?

[John Perry]

Yes, the cutouts are just handles. They are comfortable handles for moving the boat around on shore and I think they look nice but they were a bit complicated to make, particularly finishing and painting inside them. Had to fit a special handle on a paint brush. A simple bolted on handle, or perhaps just a loop of rope, would work almost as well, would save a little weight and be easier to make.

Maybe a reminder when doing drawings with a computer not to get carried away and add features just because they are easy to draw! With software such as Solidworks I can produce technical drawings maybe something like a hundred times quicker than in the old days with drawing board and setsquare, so there is a temptation to draw fancy features for the fun of it then wonder whether they are really necessary.

[John Perry]

I gave a presentation about the rowing boat covered in this thread to a meeting of the Amateur Yacht Research Society recently. For those who may be interested the Powerpoint file for this presentation can be downloaded from this link:

http://www.hostellerssailingclub.org...15-rowing-boat

[George Ray]

Nice presentation, thanks for sharing your work.

[NickW]

Nice presentation, thanks for sharing your work.

+1. There's a few nice ideas to "borrow" there.

Nick

[rgthom]

I really like the folding outriggers. It makes so much sense to fold on the vertical axis and keep the oars in place.