The Perfect River Raid Boat (PRRB)

[eric17]

Hi Chris & John,
My idea was John's current boat, with application of the "Premise" to the forefoot.
In fact, it would rather look like a Swallowboats Winsome, a little more rounded under the bow, and a little shorter ...
Eric

[John P]

Am I the John that Eric and Chris are referring to ?  I suppose that may be a silly question since you may not know who 'I' is. To clarify, I am the John who recently attended the Cobnor meeting with Josephine.

My current boat building project, still at the planning stage, will be nothing like the grey painted 'sail and oar' boat that Josephine and myself sailed to Cobnor (picture at the end of the topic for the Cobnor meeting). Rather it is to be a very simple lightweight pure rowing boat. Not a clever pedal boat like the Winsome, nor a clever pedyuloh boat like Chris Waite has made, nor even a pedal underwater flipper boat like Timmo's one. Nothing fancy, just a simple plywood boat. I am aware that there are dozens, maybe hundreds, of existing plans available for small rowboats and also that such boats are being sold second hand for a fraction of the cost of building one from plywood, but for some hard to explain reason I would still like to draw and build my own.  Perhaps other people here can understand that.

Sketches are being drawn for my new boat, but there has been a delay since I have spent the last few days as a spectator at the Weymouth Speedweek. Weymouth Speedweek is primarily an event for windsurfers and kitesurfers but a few members of the AYRS also take part with their experimental boats. I think some HBBR folk may remember those from a Barton Broard meeting? The highlight of Speedweek this year, for me at least, was the opportunity to attend a brilliant talk given by Paul Larsen who has sailed faster than any other person in history (over 65knots). What I hadn't previously realised is that Paul has a catholic interest in sailing, he recently took part in a re-enactment of Shackleton's voyage in an 18 foot boat from Elephant Island to St Georgia, including the hike across St Georgia island. They used the same type of clothing that Shackleton used, ate similar food, navigated the same way and the boat they used was a close replica of the original 'James Caird'.   Paul told us that a Discovery program about this trip will be shown in the near future, but he warned us that the television people have grossly exaggerated certain aspects - Paul modestly told us that the waves in the southern ocean were not as big, nor the gales as strong as the television people would have you believe.

John

[eric17]

Yes John, the John Perry I'm referring to is the man who wrote the http://hostellerssailingclub.org.uk/boatbuild03.htm page, and who designed, built, and currently sails a nice "grey boat"with his wife Josephine.

Even if this boat is a bit to heavy for easy launching or river rowing, I think a slightly modified version could be a perfect "pocket cruiser" for coastal sailing.
And among these modifications, the rounded forefoot (THE "Premise"), which seems to be a common obsession for Chris & me.
Only difference between Chris and me : I would prefer a "five sided hull", rather than the "dory sections" of CW's boats.

Well, my project is not a "Perfect River Raid Boat", so I stop hijacking this thread

But, to go back to the subject, an evolution (IE Octavia sized) of the Winsome, or a mongrel of your boat, John, and Octavia could be a PRRB, IMO...
I  perfectly understant 1/ you want to build your new boat, and 2/ a "simpler to build" one (= without hot water and spread eagle torture ...)!

Eric

[John P]

Well, I have done lots of sketches now, still not sure it is right.  The problem I have is that I want a boat that can be rowed by one person on their own but also can be rowed by one person with a second person as a passenger. I also favor a transom stern, partly because it gives a bit better pitch stability but mainly for aesthetic reasons - I have drawn a transom that I think looks nice so I don't want to abandon that idea!   The change from one to two persons is a big weight change in a small lightweight boat and since the transom should not be immersed with a low speed boat, it means that the boat needs to trim rather a lot bow down when two are on board, also the forward person (probably the person doing the rowing) needs to sit well forward.  I am circumventing the CW's problem with the cardboard mines by making my cardboard models inside my computer, might possibly dare to show some of these soon.   John

[Timmo]

I know it doesn't keep things quite as simple, but is there an option for water ballast (either clever and built in like Polly Wee) or just a big bottle. Sits in the stern when solo and moves to the bows when two up? If the stern seat is a little way forward toward the centre point that creates space behind it for the stowage and means the ballast gets more leverage, reduces the weight of ballast required (not that Jo looks like much weight to balance anyway!)

Another way I've pondered but never seen done yet is to have a rowing position that's near infinitely variable along a proportion of the hull. Means it can be moved to balance load or passengers/helmspeople. I can visualise a thwart running on rails with quick clamps underneath locking it in position. Not yet thought through how to move rowlocks/crutches to match unless they're attached to the thwart in some way rather than the hull. Only an idea, may regret sharing it when I consider the engineering implications and realise they can't be sensibly addressed!

Understand the benefits of a transom, is it a wineglass shape? They seem so much easier to row, though they do contrbute less to the buoyancy of the stern. Less issues with the submerged drag.

Tim.

[Ratcatcherjohn]

Tim,      I refer to your aside "(not that Jo looks like much weight to balance anyway!) ". 

 Based on past experience, it would not be much of a surprise to see that it was Jo doing a good share of the rowing and John requiring a suitable counterbalance.  A further set of calculations would then be required.

 

John       ..........of  the rodent entrapment

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Date: Thu, 24 Oct 2013 07:15:34 -0700
From: [hidden email]
To: [hidden email]
Subject: Re: The Perfect River Raid Boat (PRRB)

I know it doesn't keep things quite as simple, but is there an option for water ballast (either clever and built in like Polly Wee) or just a big bottle. Sits in the stern when solo and moves to the bows when two up? If the stern seat is a little way forward toward the centre point that creates space behind it for the stowage and means the ballast gets more leverage, reduces the weight of ballast required (not that Jo looks like much weight to balance anyway!)

Another way I've pondered but never seen done yet is to have a rowing position that's near infinitely variable along a proportion of the hull. Means it can be moved to balance load or passengers/helmspeople. I can visualise a thwart running on rails with quick clamps underneath locking it in position. Not yet thought through how to move rowlocks/crutches to match unless they're attached to the thwart in some way rather than the hull. Only an idea, may regret sharing it when I consider the engineering implications and realise they can't be sensibly addressed!

Understand the benefits of a transom, is it a wineglass shape? They seem so much easier to row, though they do contrbute less to the buoyancy of the stern. Less issues with the submerged drag.

Tim.

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[Port-Na-Storm]

John P wrote

  I am circumventing the CW's problem with the cardboard mines by making my cardboard models inside my computer, might possibly dare to show some of these soon.   John

Interesting.....................
What software are you using John?

Regards
Graham.

[John P]

Timmo wrote

Another way I've pondered but never seen done yet is to have a rowing position that's near infinitely variable along a proportion of the hull. Means it can be moved to balance load or passengers/helmspeople. I can visualise a thwart running on rails with quick clamps underneath locking it in position. Not yet thought through how to move rowlocks/crutches to match unless they're attached to the thwart in some way rather than the hull. Only an idea, may regret sharing it when I consider the engineering implications and realise they can't be sensibly addressed!

Understand the benefits of a transom, is it a wineglass shape? They seem so much easier to row, though they do contrbute less to the buoyancy of the stern. Less issues with the submerged drag.

Tim.

You seem to have a remarkable mind reading ability Tim!  Yes, I am thinking of 'rails' running fore and aft so that a thwart can be mounted on the rails in a position to suit whatever crew weight is on board at the time. It will actually be a sliding seat kind of arrangement as used on the racing rowing boats, but Chis P. tells me that for the kind of rowing Josephine and myself are likely to be doing I probably would not find a sliding seat much advantage. At least, with the rails, I can try it either way, for a fixed seat I lock the seat to the rails with a couple of bolts, for a sliding seat let it slide. I am hoping that just two rowlock positions will be sufficient, a forward position for one person on board and an aft position for two persons. I don't think that is particularly unusual.

It might actually be possible to also include the option to mount a sliding rowlock thing on the rails, remember Gerald T.'s new skiff at Cobnor? Could be interesting to have the option to compare all three ways of rowing. But lots of wood butchering and sticky spreading to do before that would be possible!

No, I wasnt thinking of a wineglass transom, although there is much to be said for that shape in that if the 'stem' of the wineglass is narrow you can probably allow the transom to submerge some way before you get much extra drag.  I was thinking more of a transom as on our 'grey boat', but much narrower. This has a straight bottom edge paralell with the waterline and just above the waterline. Don't really want a transom like that to drag in the water too much.  A lot of this is a matter of aesthetics.

John

[John P]

Port-Na-Storm wrote

Interesting.....................
What software are you using John?

Regards
Graham.

I tend to think that asking someone what software they are using is a bit like saying to an author fifty years ago 'that was a good book you wrote, tell me, did you use a biro or a fountain pen?'

But since you ask, I am currently using Solidworks.

John

[Chris Partridge]

John -
Take a look at the Wemys skiff, designed by Iain Oughtred and Alec Jordan (http://jordanboats.co.uk/JB/wemyss_skiff.htm). It has flotation chambers arranged along the sides of the boat with a gap between, so you can place the rowing thwart anywhere you like. This means that you can very easily move between rowing positions, one at the centre for solo rowing and one nearer the bow when carrying a passenger/cox. You could even have a second thwart for double sculling.
The extra advantage of a transom is that it makes it easier to mount a rudder.
I wouldn't bother with a sliding seat. It's complex and gets in the way when you want to move about the boat. And it does you no real good unless you are racing. The kind of boat you are designing can be driven along at hull speed quite nicely without a sliding seat.
Chris

[Chris Partridge]

Moving the rowlocks is easy - just mount a pair of sockets on the gunwales at each rowing station.

[Chris Waite]

Oooh, a gurt great hairy discussion

My absolute favourite!

I am very much in agreement with you Johnny P – a light rowing hull and it has to double up as a picnic-for-two-on-the-river vessel.  I cannot afford to build such a boat merely to use it from Lechlade to Beale once a year; and anyway our girls are entitled to join in the fun.

Further to that, as you indicate, designing and building your own is the essence of the adventure.  You never know, it might suit you better than any old something from someone else’s drawing board, or second hand.  On the front of ‘Watercraft’, under the title, there is the legend:

“Designing boats, building boats, using boats”

– that has become my coincidental philosophy.

Next, Eric’s comment on hot water and spread-eagles, refers to my pinning down the floor of ‘Polly Wee’ on a frame that would not disgrace the most hideous dungeon and continuing on to pour boiling water over the ply to get it to bend:

 

There is a much simpler solution –

Use the right ply, idiot!  I still can’t afford Robbin’s finest for my eminently suspect creations, but I gave up with cheap and brittle WBP and have gone up-market to beautiful birch – it bends a treat on the decks of ‘Polly Wee’ and it now comes to mind that actually I even used a batch of the stuff from B&Q to build ‘Octavia’ (and for those of you tutting in the background, five years on and there’s no sign of rot).

Going on I also agree with John about the transom.  All my current designs incorporate a skeg aft. whose bottom edge runs level with the lowest point of the rocker (curve of the keel) and fills in the triangle between that and the bottom of the transom:



Some may feel that this reduces manoeuvrability, but of the two, inducing directional stability has caused me more problems.  Anyway, I’m going on to agree with whoever (?Chris Partridge) that a rudder should be included in the mix; after all, it doesn’t actually have to be permanently in-situ.

What shape of transom?  Again I agree, the lowest point of the transom should just reach down to the waterline.  A good idea in theory, but difficult to calculate in practice (which cyberoprogram would you recommend?).  Particularly how do you allow for just the boat and the oarsman, or you and the girl out for a picnic, or you rowing your bundled up marquee, complete with kitchen sink, larder, wine cellar and hanging wardrobe, down a river for a week.  The ‘wineglass’ shape is much more forgiving in this respect, but a battle to build:

   

Here is ‘Octavia’, propelled by the provider of the beautiful gold leaf lettering on her hopefully tasteful tush.  The meanderingly aesthetic right side of my brain has the urge to dive back into this particular swamp of impossible geometry, but the sensible left side is telling me that the ‘Premise’ on which the hull is designed includes a one piece floor that only curves around under the lower edge of the transom, like ‘Polly Wee’:



Further, that of all the possible ways in which one can fail to keep up with the rest of the fleet, trailing two umpteeths of the transom is a pretty smallish part.  The (skeg) draft on ‘Polly Wee’ is 6.75 inches and the never-swamped-yet, dividing bulkhead between ‘Octavia’s two halves is 7.5 inches high.  ‘Curvy Mabel’ is somewhere between the two in length and beam, but will be much lighter than either of them, (won’t she Christopher Waite?) and I currently expect a comfortably loaded draft of about 6 inches, so that is where the transom will reach down to

Counter-claims on a PC please??

And on to rowlocks….

‘Octavia’ needed outriggers to make best use of her long narrow hull.  She also has the two position problem associated with an occasional passenger.  To achieve this, the outriggers have transmogrified into two seriously substantial ‘wings’ that also help strap the fore and aft halves of the boat together.  On going from one to two PoB, these wings are changed side for side, advancing the rowlocks from their aft position to the forward one:

 





At the same time, the forward end of the hull has side tanks, presumably similar to those described by ChristoPart and the oarsman’s seat is merely shifted along these until it in the right place for either one or two PoB:

 

However, this time I agree with that gentleman; two sets of sockets.  The only problem with this is that the hull is narrower forward than it is amidships, so I wondered if it would be possible to maintain the athwartships distance between rowlocks by mounting the aft (single oarsman) set inboard of the gunwales and the forward (oarsman and passenger) set outboard, possibly on extra chocks if need be.

PoB?  Possums on Board

CW



The transom cometh….
next

[Paul H (admin)]

Chris Waite wrote

rowing your bundled up marquee, complete with kitchen sink, larder, wine cellar and hanging wardrobe, down a river for a week.

Don't forget 2 batteries, charger, solar panel, HD smart phone with GPS and the mother-of-all electric mixers.

[eric17]

PRRB from France : http://chantiermer.wordpress.com/actualite/brol/

 

"Brol", by Gilles Montaubin :
5m x 0,88m, 64 kg (80 kg with all sailing gear)
400 L storage, mast furling sails.
(Who was asking for a slimmer Winsome ?)
with "hollow cheeks", alas, Chris

Eric

[BrianP]

Eric I think you just posted the most Perfect River raid Boat I have ever seen. 34.6" wide with folding outriggers, loads of storage and sleeping room. She's in sailing canoe territory yet not a canoe. The long vertical sail batten which creates sail area on a short mast but allows sail rolling reefing around the mast which works so well on the Hobies.

Here's a rough Chrome translation of the designers notes

The "brol" is slang brussellois a "thing", a "trick unlikely!"
The boat is as follows: a strange marriage between a sea skiff and a canoe sailing turn of the century (Rob Roy and others)
But see its possible uses in view of its characteristics:

Gig rowing : 5m x 0.88 (5m12 x 1m12) waterline give it a good elongation combined with a shell 64 kg, well defended from the front, a cart with wheels and folding outriggers bringing the width between oarlocks to 1m46. These are the attributes to row well and fast and long, alone or with a skipper to relay.


Sailboat : 2 Mylar sails 5m2 and 1.50 m2 give low sailing center to compensate for the narrow width. A curb weight of 80kg and a high prismatic coefficient provides interesting upwind performance through a sand drift with the draft to 70 cm, and with an AR with hovering.

Safety is not forgotten as the reduction by rolling sails is quick and easy, while maintaining the balance of the boat, the skipper can sit on the outrigger to windward for an effective recall, most of the boat is unsinkable and self-bailing cockpit.

Rowing sail : with this double performance propulsion, the owner may participate in raids sailing / rowing that exist everywhere in Europe, especially as congestion is minimized.


Coastal Hiking : 2 watertight boxes front and rear (about 220l each) allow to carry everything you need for rides in total autonomy (sleeping, food, safety ...), because the cockpit can accommodate a flat protected by sleeper an awning stretched between two poles.

This is therefore an important range of water sports available with a safe, efficient boat, an easy to land and economic as possible at various stages handling plan with complete gross hull with any file to finish up "bar in hand "

Perhaps add a Hobie Drive option to make her just perfect.

Brian

[Chris Partridge]

With respect, Brian, I disagree. For river raids, sailing is so impractical it would be far better to leave the rig at home so it doesn't get in the way when rowing and sleeping.
Not having a rig would also give sailors peace of mind. They wouldn't spend the entire raid looking for wind that wasn't right on the nose. I have seen them (you know who you are!) getting really depressed about this. As John Cleese's headmaster character put it in Clockwise, when the pupil told him not to despair: "I can stand the despair. It's the hope."
I have come to the initial, preliminary and provisional conclusion that the ideal river raid boat is this:

[Randonneur]

> I have come to the initial, preliminary and provisional conclusion that the ideal river raid boat is this:

In that case you'd better not miss:
Crossing England in a punt. River of Dreams.

http://www.bbc.co.uk/mobile/iplayer/episode/p00y6r6q

Which expires today.
I think he has your PRRB!

[alopenboat]

On 27 Oct 2013 at 3:30, Chris Partridge [via UK HBBR Forum] wrote:

>
>
> With respect, Brian, I disagree. For river raids, sailing is so
> impractical it would be far better to leave the rig at home so it
> doesn't get in the way when rowing and sleeping.

I have to agree with Chris here. On the Thames, from Lechlade to
Walton, with my easily deployed rig, I sailed maybe 10% of the
distance. On the Kennet I didn't sail at all.

--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[Randonneur]

That link would have been better as:

http://www.bbc.co.uk/i/p00y6r6q/
or
http://www.bbc.co.uk/programmes/p00y6r6q

from a desktop PC.

Ends today.



From the Staffordshire hills to the Humber estuary, spirited explorer Tom Fort embarks on a 170-mile journey down Britain's third longest river, the Trent. Beginning on foot, he soon transfers to his own custom-built punt, the Trent Otter

[Chris Waite]

Yesterday morning, I only narrowly avoided

A small confederation of aesthetics (not anaesthetics – not quite) coming the other way; the transom has been causing some concern.

It needs to be wide enough to take the ‘Pedyuloh’ turning blocks in the quarters; 27 inches I have decided.  Also the shear strakes, or ‘sides’ as they are known in the design office here, need to draw in to minimize her rear, which naturally brings the top of the stern to 18 inches above the keel; so to give the 6 inch draft I have likewise picked out of the ether, the height of the transom needs to be a foot.  This was threatening to produce a backside with the dramatic impact of a barn door; far from ‘Octavia’s tight little tush.

With trepidation, I drew up it in my mind’s eye freehand, (just the one side dear, the other is a mirror image) and trembling slightly, stuck it in.  Sigh of relief; to me it looks better than I deserve and honestly diminishes the necessity to go down the wineglass route:



Bring on the simple life….

Anyway, there needs to be some extra buoyancy available around her nethers* as, not only will there be the occasional passenger, I am hoping the ‘Pedyuloh’ will be a major means of propulsion; working at some 45 degrees it must tend to push down on the stern as well as any forward element.  Interestingly setting the yuloh more vertically than this seems to reduce, rather than improve its performance, but that is another story.  (*Well if animals have ‘withers’ which are the highest point of the body forward, I’ve decided that boats should be allowed ‘nethers’, being something like the lowest point aft.  Any good?)

So yesterday afternoon I applied the bottom, the garboard strake(?) and tidied up and adding a skeg, to be sure that people know I’m not lying, making the model of ‘Curvy Mabel’s hull complete.  Now forgive me too Brian, but Eric’s discovery ‘Brol’ is pretty much one more Sharpie, almost identical to the 12 Square Metre dinghies, (though a fair bit lighter and probably somewhat smaller):

 

Acknowledging the difference in the ‘floorpan’, not so very far off your ‘Flattie’ of a few years back.

I thought naming my dreamboat ‘Curvy Mabel’ was stretching a point a tad until I saw ‘Brol’, but I am now sufficiently encouraged to let the name stand:

 

 

Now I suppose I have to build the real one?

Gerontius

(I also agree using sails to go anywhere our inland rivers and canals is a mug’s game and not worth the biscuit)