Rowing/electric cruising boat

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GregHBBR GregHBBR
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Re: Rowing/electric cruising boat

Hi Paul,

The maximum file upload, via the "More" button, is 5Mb. The limit for images uploaded via the "Insert Image" button is 1Mb.
Greg Chapman
GregAfloat - My Boating Biography
Chris Waite Chris Waite
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Re: Rowing/electric cruising boat

In reply to this post by Paul H (admin)
It also depends

On how long you want to spend fiddling around for increasingly little increase in speed and beauty:

a.  Sixteen feet is two ply boards, butt-jointed end-to-end

b.  To produce a hull with any volume and stability does not even require a keel, just two chines -

Curvy Mabel - a PRRB

 

In fact the road to hull is paved

With good inventions

CW  

Timmo Timmo
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Re: Rowing/electric cruising boat

In reply to this post by Paul H (admin)
The Excel file as requested.

Zelva_1st_draft_offsets.xlsx

You will note that the sections are drawn by crudely overlaying a number of graphs. Fiddly and they don't line up perfectly. But after playing with the numbers to create graphs that pleased my eye I had enough confidence to build the quarter model:

 

That was then tweaked to create the moulds:



The lands of the strakes were marked with the battens, so further tweaking took place before the actual planks went on:



Result worked, more by luck than judgement! Idiosyncratic is probably the kindest description, but she does exactly what I need rather well.



Should really learn a proper boat design programme, but I haven't found a free/cheap one (preferably for Mac OS) that you can put offsets into as a starting point. Suggestions welcome!

Tim.
Paul H (admin) Paul H (admin)
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Re: Rowing/electric cruising boat

In reply to this post by Chris Waite
Nice design Chris - can you email me the cardboard shapes? There's a challenge for you, that might involve a little cutting and ironing and scanning.

Isn't her rear end a tad big for low drag?  I don't mean a weekend drag queen.  

What L x W does your mercurial geometrical invention produce?

Yes life is short:

The boat is long
With many a winding turn
That leads us to who knows where
Who knows where

But I'm strong,
She ain't heavy,...... she's my Mabel



-P


Chris Partridge Chris Partridge
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Re: Rowing/electric cruising boat

In reply to this post by Chris Waite
Now that is a nice shape.
The deep forefoot and skeg should keep her in line nicely.
The big transom holds an electric outboard securely and provides lots of buoyancy at the back to keep it out of the water.
The almost flat midships section will keep her upright when dried out in DCA rallies.
What's the beam, CW?
The only worry is how bendy the boards need to be. How thick does the ply need to be? Will this be a really light boat?
I feel a build coming on...
Paul H (admin) Paul H (admin)
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Re: Rowing/electric cruising boat

Chris,

CDubs rules mean the bottom sheets will be 2ft wide max. Easily cut from 2 sheets.
So the beam could be 4ft plus the side panels "V width".

Electric outboards can go anywhere you can mount the 1in shaft and they are much lighter than a petrol engine. So there is no need to drag a big transom around. Something like a Thames skiff shape is one option. But pointy at both ends will extend the battery distance.

Paul
Timmo Timmo
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Re: Rowing/electric cruising boat

Or some variation on a wine glass transom, so the water thinks the stern is pointy while above the waterline there's flat area to clamp motors to.

Can look good too.

Tim.


On 16 Oct 2016, at 11:03, Paul (admin) [via UK HBBR Forum] <[hidden email]> wrote:

Chris,

CDubs rules mean the bottom sheets will be 2ft wide max. Easily cut from 2 sheets.
So the beam could be 4ft plus the side panels "V width".

Electric outboards can go anywhere you can mount the 1in shaft and they are much lighter than a petrol engine. So there is no need to drag a big transom around. Something like a Thames skiff shape is one option. But pointy at both ends will extend the battery distance.

Paul
Sail when you can, motor when you can't http://www.millibee.co.uk



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Chris Waite Chris Waite
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Re: Rowing/electric cruising boat

Wow, I didn't quite expect this discussion right now

But what the hell?

Paulie, I'll see if I can knock up the bits for a (half) model all of your very own; don't hold your breath.

1.  This Premise 16 Skiff is (obviously) just under sixteen foot, as that length has to go round to form the side strakes.

2.  No Paulie - not a twenty-four inch flat floor; she would be like Octavia, too narrow to reasonably sleep aboard and not really have sufficient carrying capacity, but with my abiding attraction to the four x eight foot ply-board rule, 48" divides neatly into three.  So sixteen inches maximum depth of the sides and 2 x 16" = 32" maximum beam across the floor.  Flaring 16" sides out 6" gives the same angle as Polly Wee at this point - 0.6 of the LOA from the stem, making the maximum beam here 44" (32" + 6" + 6").  Three sheets for the hull, excluding the transom, but with one 8' x 16" slice left over.

For rowing, she would probably benefit from stubby outriggers, which I would hinge over the gunwales.

3.  It would be possible to install the same type of wineglass stern that Octavia sported, but this requires some pretty fancy bodging to achieve -

 Grum, I think this picture is one of yours?  Thanks

The stern on the cardboard cut-out above, is much easier to produce.  It is that size for the following reasons -

a.  The lower curve of the transom as it reaches down to meet the floor is some four inches above the flat bottom; note the skeg infill.  This should allow this point to just kiss the wake with camping kit and 1 POB.  A tad below the Plimsoll Line with two and a picnic, or not quite with just one unencumbered crew.  I do not know what water thinks of a skeg showing at this point, but I suspect it may go off into a corner with a calculator and disallow the waterline length you were hoping for.  Life is a compromise.

b.  The width allows for more buoyancy under a full load, and/or outboard if you must.  More importantly for me, it provides sufficient distance between the quarters to mount my Pedyuloh turning blocks there -



.... but I can shrink it to fit whatever your little heart desires; even a canoe stern.

4.  Christo von Partridge, I have already bought some 4mm WBP birch ply for the project; not as light as some stuff, but beautifully bendy and the outside of the hull at least will, as ever, be Tesco-polycotton/epoxy sheathed.

I only have a house to finish remodelling first

5.  Just so's you know, the Pedyuloh will be mounted on the stock of a small rudder with a fixed blade protruding perhaps six inches below the flat bottom.  While you can turn with just the yuloh, it will not undertake tight turns in rivers -



....or according to Octavia to compensate for the bow blowing off in a head wind; (noting 6. below a small centreboard, well forward has been slicing through my reveries).  Why on the stock?  Because it should reduce the reverberating clonk from the yuloh self-cocking at every stroke and if you think about it, it will tend to produce a turning moment that cancels out any tendency of the boat to yaw back and forth under the influence of the yuloh itself.

6.  I also have notions of a down-wind-ish sort of rig - probably not more than forty square feet, which would have an unstayed mast hinged in a slim, removable tabernacle reaching a good couple of feet above the deck, for headroom purposes.  The quadrilateral, boomed sail, (possibly sliding) goose-neck on the back of the tabernacle, with one moderately flexible, built-in batten from clew to peak and the sail sleeved round the mast would be hoisted on a running forestay, lead back to the cockpit.  With a semi-permanently fixed 'Y' (or possibly gallows-type) crutch behind the pedyulist.  Raise or stow the mast-sail combination on the forestay - one string and one other as a sheet.

Food for thought?

CW    

simplesimon simplesimon
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Re: Rowing/electric cruising boat

Chris W
I think Paul meant a vee-bottom wth a 24" garboard strake each side.

Actually a 24" flattish bottom works reasonable well provided you flare out the planking to give a waterline beam of around 32" or more, and an overall beam of 42" plus. Won't all come out of two 48" wide sheets though, needs a third sheet to provide the top strakes.

Cheers
Simon
Paul H (admin) Paul H (admin)
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Re: Rowing/electric cruising boat

I'm leaning towards a stretched version of Zeldah...maybe 18ft+, maybe extended enough for the fixed sleeping area Tim suggested. A flattish deck to sleep under with solar panels on top. And just 3 planks per side.....life is short

I'd put the motor on the Port side, simply to avoid trees, reeds and sandbanks along rivers. It needs to tilt quickly to clear weed and sticks from the propellor, so whilst Graham's idea of a well is good having to lift the motor vertically to clear weed is a no-no. So it would be just behind maximum beam, outside the Port side with an option for the Starboard side.

I've seen Zeldah glide through the water at speed - hopefully 3 panels per side will approximate her shape well enough, might need 4 for a fine entry and exit.

Batteries need to flexible. There are Lithium batteries appearing for golf buggies that are 1/4 the weight of lead-acid batteries - too expensive at the moment.

An out rigger for rowing like the RowCruiser.....Angus adds small pods under the rowlocks which might help docking. Need a bit more thought there.

-Paul
LASER41420 LASER41420
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Re: Rowing/electric cruising boat

Hi,
Quite happy with my evolving folding outriggers, a couple of alloy/nylon hinges each side and docking and locking became a pleasure.
Steve
Chris Waite Chris Waite
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Re: Rowing/electric cruising boat

In reply to this post by simplesimon
You’re right Simon, I had to go back and re-read

So Squire Paulie of Hucclecote, you were referring to a ‘floor’ that is four foot wide.  No vee-bottom, would not fit in with my previous comment about the avoidance of having to form a keel.  Anyway, four-foot-botties moves us over to the next can of worms.  There is no real point in designing anything else flat bottomed like this as there are already any number of hulls up to sixteen feet, based on four foot-ish floors; Conrad Natzio’s Oystercatcher, the Paradox (14’), some of Gavin Atkins designs I think, Storer’s Raid 41 and Goat Island Skiff; sort of thing.

Then if you are talking about a vee-bottom, there are the traditional single chine hulls – the GP 14 and the old Hornet come to mind.  Making a canoe stern on a four foot wide flat floor at this length, while possible, starts to create some blobby, but perhaps not impossible shapes.  I also have to tell you that you can get a perfectly serviceable 16’ rowing shell, out of two ply sheets –

 
 

Now onto a particular 'Premise' of mine.  Sixteen feet round the sides, five foot six inch beam, with a four foot wide flat bottom – offered to Wayne as a next project after Ever Hopeful

 

This is another thing I would still love to build one day; the transom on this one is quite large and boxy - useful for planing/downwind.  It is a two ‘man’ version of my Premise 12, Polly Wee



And as I’m being old-goatly on line; a while ago, you picked me up on suggesting the use of steel wire as a suture material for stitch and tape.  I said that I removed the stitches and you warned that some wire might get left behind to rust.  Not in my obsessional little world; I set up the joint with intervening epoxied fillets between the stitches, or glass tabs where there is insufficient angle between the strakes.  Then before any epoxy encroaches on a suture, I snip each one individually and pull it clear.

QEF – Quite Easily Fudged

Just like a real doctor

In fact

Chris    
BrianP BrianP
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Re: Rowing/electric cruising boat




Chris, that's rather nice.
ChrisC ChrisC
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Re: Rowing/electric cruising boat

What a very interesting thread!  A human/electric hybrid really appeals but since I am moderately obsessed with Venetian rowing I would stand up, face forward and mount the prop off centre so that the single oar would provide the balanced thrust.  Motor control could be by footswitch as below but I suppose the modern way would be to have some kind of bluetooth thumbswitch on the oar handle?

http://www.gondolagreg.com/2010/03/unique-features-and-operation-of.html
BrianP BrianP
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Re: Rowing/electric cruising boat

Timmo Timmo
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Re: Rowing/electric cruising boat

In reply to this post by ChrisC
I've tried venetian rowing. Being able to see where you're going worked for me. Also avoids the need to seek out quality padding for a seat! 

If the intention is to use human power and electric power simultaneously it's probably worth thinking about the hull speed of the boat. In many shorter (12-14ft) canoes or rowing boats it's relatively easy to push many hulls to their hull speed just with human power. Likewise the number of boats you see squatting, kicking up oversized wakes, deomonstrates it's easy to waste outboard power.

So to avoid wasting power I think it will be important to have sufficiant waterline length to allow for a hul speed that will merit the compination of power inputs!

Tim.


On 19 Oct 2016, at 18:32, ChrisC [via UK HBBR Forum] <[hidden email]> wrote:

What a very interesting thread!  A human/electric hybrid really appeals but since I am moderately obsessed with Venetian rowing I would stand up, face forward and mount the prop off centre so that the single oar would provide the balanced thrust.  Motor control could be by footswitch as below but I suppose the modern way would be to have some kind of bluetooth thumbswitch on the oar handle?

http://www.gondolagreg.com/2010/03/unique-features-and-operation-of.html


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pete@watercraft-magazine.com pete@watercraft-magazine.com
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Re: Rowing/electric cruising boat

In reply to this post by BrianP
Thanks, Brian. Fascinating bit of kit. If Water Craft can borrow one, would you, Tim or anyone else to whom it appeals – maybe with a better hull but with equally impressive legs – review for us in the magazine?

Pete G, Water Craft magazine.
Chris Partridge Chris Partridge
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Re: Rowing/electric cruising boat

I think it will have to be imported from Brazil and it won't be cheap. Also, my Portuguese isn't up to the job. The makers are on Facebook however so contact should be possible.
Chris Partridge Chris Partridge
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Re: Rowing/electric cruising boat

In reply to this post by Timmo
Pushing the boat to hull speed is not the problem, it is the distance. A discrete push along should enable rowers to keep up with sailors on cruising events, especially as the outboard will keep the boat moving in the recovery phase when the oars are out of the water.
Chris Waite Chris Waite
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Re: Rowing/electric cruising boat

In reply to this post by ChrisC
I've actually said this before Chris

Several times, my longer serving chums will tell you - I don't think my stubby little sailors legs would consider 'standing' for a whole holiday.  I like to be sitting down to enjoy my watery recuperations.

Hence, as they will also tell you, I linked a yuloh to some stirrup pedals - a Pedyuloh so I can sit facing forward and pedal my butt down the river; bear with the other boat(s) on this video, I was just lucky Chris Partridge was kind enough to do some filming -

https://www.youtube.com/watch?v=O2CxQbwjNMo&feature=player_embedded

That was one of my earlier attempts, but it is now sufficiently refined for me to have successfully undertaken three, or four Lechlade to Beale Thames raids with it.  It drives a sixteen foot skiff very adequately.

Twice as cheap as chips

But does the biz

Chris W

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