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There
is a report about one being built here on the OZ woodwork forums..
And now another one
And another one
Download the Free Plan Drawing for the oars here (PDF File - 24k), but you also need the
Free Paddle Plan PDF File (300Kb) - This has the details on methods and order of assembly
General
Comments
This
design has had a very long gestation – over two years. My normal
well-documented plans were around half way finished and I just
couldn't continue – a sure sign there was something I wasn't quite
happy with. I scrapped the whole thing and started again a few weeks
ago.
Generally
I don't design boats to order but in this case two emails from old
boatbuilding friends prompted the development of this boat. Initially I
headed in the direction of something much more racey, but
then realised that Peter and Richard wanted speed but with more
flexibility.
The
racey version was finally rejected when Peter asked me about where he
was going to cut the bait!
So it evolved in a more sensible direction.
The
Never Ending Dory
For
some time I've thought of using the Goat Island Skiff (GIS) design as
the basis for a rowboat – more slender, lighter, lower.
It
also is a response to the number of lightweight plywood dory designs
that are around these days. Old dories weighed hundreds of pounds
and were around 20ft long overall and are reputed to need a good load
of fish to make them into stable platforms – shrink them and
lighten them and the stability drops off very rapidly.
Of
the modern, shorter, lightweight dorys, the better ones of the modern
kind paddle
very easily but are tender until you have a load aboard
and their speed is limited by the short waterline. The
worse ones are so twitchy as to be almost useless.
Some
try to fudge a dory shape by having curved clinker sides. But then
you lose the simplicity. This rowboat is not really suited to wavey
oceans, but will be fine in estuaries are rivers where there is a
chop.
The
Emails
Peter
wrote:
On
thinking about the rowing boat brief.... no,
dash it all NO passengers, if she wants to come we'll go in Gruff (ie
the Goat Island Skiff) or the canoe!
Sooo...
two sheets of ply long, needs to be a bit more utilitarian than a
shell, so that one can cast a line or pick up a crab pot, but really
it's a boat for the sheer pleasure of going for a row.
I
don't know too much about rowing properly, but a sliding seat option
may be ok??
Has
to be pretty, which is why I'm keen for you to look at it! The
Goat Island Skiff with a foot out of the beam??
My
response:
Was
to say, yes, yes, yes – but Richard had slightly different criteria
as far as payload.
Richard
wrote:
For
efficient rowing on the river (Murray) - so against current, some
chop, wake from power boats, but not open ocean or rough water. Come
to think of it, the wake thrown up by your average yahoo driven ski
boat probably qualifies for 'rough water', especially as I'll often
have my little daughter in the 'boss's seat'.
Will
be used for fishing (I sit when I fish in a boat) and exploring. Cheap
to build without sacrificing usability.
Light
- although this boat will be carried on a trailer, it will be
launched and recovered from river banks, not boat ramps. Light
enough to car top or for one person to carry would be nice but not
essential. I'm after a tough, light, utility boat, not an ultra-light
weapon.
Enough
floatation for safety if swamped - I'm not some panic merchant who
expects it to float on its water line when full of water - just high
enough to get back into.
My
Response:
Again
– Yes. A move toward general use as Richard describes willl also
make the plans more interesting to more people.
She
will float a little deep with three aboard but by keeping the base of
the transom narrow and shallow any bad effects will be minimal. I
think she will prefer to carry three lighter individuals or a heavier
adult a lighter adult and a child – though she will be at her best
one up.
The
front and back seats take up a lot of the boat length for a safety
factor but also to push the passengers toward the middle of the boat.
The middle seat is very wide so there can be two sets of rowlock
sockets – front one for when there is a passenger in the back. It
can be used for storage or batteries if using a electric trolling
outboard.
A
Quick Model
I
drew up shape on the computer and emailed some panel outlines so
models could be made by both interested parties – they are both
experienced boatbuilders.
The
photos of the rowboat model arrived the next morning! Peter whipped
it up overnight and photographed it with the red timber glowing in
the morning light. The white boat is the model of the Goat Island
Skiff that Peter built years ago. Scale is approximately similar.
The
version that has been developed since has more side panel flare to
give a larger beam for more stability and to carry 8ft oars without
outriggers.
Aesthetics
Both
Peter and Richard were quite happy with the appearance from the model
- as was I.
On
double checking the dimensions and found that the bow had crept up
too high - almost 500mm above the waterline - it would have caught
the wind very badly – so it has been reduced but with a fraction
more sheer in the stern. The wireframe drawing reflects the current
shape.
Technical
 It
is interesting to compare the shape of the rowboat with the Goat
Island Skiff (GIS - right) which was based around an
excellent
sailing performance. Both are simple hullshapes, but rowboats have
much less power available.
- Wetted Surface is reduced in the
rowboat by narrowing the width of the bottom throughout, particularly
in the stern. It was tempting to go toward a canoe stern, but it would
sink heavily when a passenger was in the back seat and would reduce
stability for other uses.
- The bottom width is reduced but the
width at the gunwale retained to provide a good base for oars. Oar
length is approximately twice the beam so if the beam becomes too small
then the oars have to shrink too - for less efficiency.
- Prismatic
co-efficient (CP) is a measure of how much volume is in the
ends of the boat. Light sailing boats like the sail powered GIS can
easily average 6 to 8 knots so need extra volume in the stern and bow
at speed. The rowboat will only ever get up to around 3.5 to 4 knots so
the CP needs to be lower. It was hard to achieve the
exact numbers required because of the transom width so we have gone as
far as possible. Getting rid of the passenger and having a canoe stern
would make it easier to get the right numbers.
It ends up looking quite a delicate little thing.
Conclusion
I haven't come up with the right
name for this boat yet so it remains the MSD Rowing Skiff. It
actually fits nicely within my range – some people build the Goat
Island Skiff to serve as a rowboat where it is more than adequate
when fitted with a skeg. But where less capacity, more speed for the
same effort and the ability to cartop (narrower and lighter) is more
important the Rowing Skiff will be more suitable. Plans are $75 and
the boat will use up 4 sheets of 6mm ply.
This is the original
webpage.
 Two
emails prompted the
development of this boat (above). Initially I headed in the
direction of something much more racey (image right), but then realised
that both Peter and Richard wanted something with some speed but more
flexibility. The racey version was finally rejected when
Peter asked me about where he was going to cut the bait.
So I drew up an
approximate shape and provided some panel outlines so models could be
made by Peter and Richard.
The photos of the
rowboat model (red timber - doesn't it look
good in
the morning light!) that Peter whipped up overnight are with the model
of the
Goat
Island Skiff
that Peter built years ago. Scale is
approximately similar. The wireframe drawing of the boat at
this stage is below.
Peter
wrote:
 Nice talking to you, glad to
hear you are in fine spirits.
On thinking about the rowing
boat brief....
No, dash it all NO
passengers, if she wants to come we'll go in Gruff (ie the
Goat Island Skiff) or the canoe!
Sooo... two sheets of ply
long, payload 100 kg (I'm 85 and I reckon 15 of bait), needs to be
a bit more utilitarian than a shell, so that one can cast a line or
pick up a crab pot, but really it's a boat for the sheer pleasure of going for a row.
I don't know too
much about rowing properly, but a sliding seat option may be ok??
Has to be pretty, which is why I'm keen for you to look at it!
Gruff with a foot
out of the beam??
Richard wrote:
Designed
for efficient rowing - on the river so against
current,
some chop, wake from power boats, but not open ocean or rough
water. Some offshore work but only on flat days. Come to think
of
it, the wake thrown up by your average yahoo driven ski boat probably
qualifies for 'rough water', especially as I'll often have my little
daughter in the 'boss's seat'.
Will be rowed in stiff cross winds so some directional
stability would be nice (ie, a bloody big skeg).
No sails, nor do I want the hull widened to make it better
for sails -
this is a row boat. To carry myself and my daughter -
she's four but growing so say two adults minimum, with a third
in
the bow.
 Will be used for fishing (I
sit when I fish in a boat) and
exploring. Will be rowed some distance at times.
Eventually, I'll have a 3hp outboard for my Yellowtail and
should
imagine I'll be tempted
to bung it on the row boat at times.
Cheap to build without sacrificing usability - stitch and
glue is
frowned on here due to the horrendous amount of epoxy it uses
(I'm still gasping at the amount that goes into an 8'
Mouseboat),
as is fibreglassing the bottom. I could be convinced to go stitch
and glue but am wary of acres of fibreglass.
Light - although this boat will be carried on a trailer, it
will
be launched and recovered from river banks, not boat ramps.
Light
enough to car top or for one person to carry would be nice but
not essential. I'm after a tough, light, utility boat, not an
ultra-light weapon.
Rowing stations to suit single rower, rower and passenger in
stern, and provision for a scull on the transom. I
make my
own oars so Mike can specify any weird sizes that he likes.
Enough floatation for safety if swamped - perhaps under the
rear and
bow seats. I shouldn't imagine this boat'd need much and
I'm not
some panic merchant who expects it to float on its water
line when
full of water - just high enough to get back into.
Aesthetics
Both Peter and Richard were quite happy with the appearance - as was
I. So I double checked the dimensions and found that the bow
had
crept up too high - almost 500mm above the waterline - it would have
caught the wind very badly - so I reduced the bow height and
to
keep it looking sweet put a fraction more sheer in the stern.
The
wireframe drawing at the top reflects the current shape.
Buoyancy
tanks are set up as the passenger seats front and back and are quite
generous providing a good safety factor as well as pushing the
passengers toward the centre of the boat where they will upset the trim
less.
Technical
It is
interesting to compare
the shape of the rowboat with the Goat Island Skiff (GIS) which was
based around an excellent sailing performance. Both are
simple
hullshapes, but rowboats have much less power available.
- Wetted Surface is reduced by
narrowing the beam,
particularly in the stern. It is further reduced by reducing
the
width of the bottom. It was tempting to go toward a canoe
stern,
but the stern would sink heavily when a passenger was in the back seat
- rather against what Richard was after in his boat.
- The
bottom width can be reduced but the width at
the gunwale needs
to be retained to provide a good base for oars. Basically oar
length is approximately twice the beam so if the beam becomes too small
then the oars have to shrink proportionately - for less
efficiency. So hull bottom width is reduced and gunwale width
is retained by increasing hull flare.
- Prismatic
co-efficient (Cp) is a measure of how
much volume
is in the ends of the boat. For faster boats there needs to
be
more volume in the ends. The GIS as a sailing boat needs the
extra width of the
stern and bow because its speed will range up to about 12 or 14 knots
with a reasonable design average of 6 knots - a little
above the hull speed
limit. The rowboat will only
ever get up to around 3.5 to 4 knots so the Cp needs to be much
lower. In actuality it is very hard to reduce the Cp
adequately
in a transom sterned flat bottomed rowboat so we have gone as far as
possible in the right direction. It would be much easier to
hit
the Cp on the button if the boat didn't have to carry a passenger -
which would allow the canoe stern option.
 Working
Drawings and Instruction Pack
Having the basic
hullshape is about 5% of the work involved in developing a working plan.
- All hull panels have to fit
on the plywood neatly
to use the
materials efficiently and keep the weight well down (note the drawing
on the right is distorted but will give you an idea)
- Construction has to be
logical to save labour time and to make sure the hullshape comes out
accurately in a reproduceable way.
- A
full set of instructions need to be written to
guide a non
boat builder to handle the building procedure and the building
materials - plywood, epoxy, fibreglass tape and timber.
Getting
Stuck
I
have had a couple of problems bugging me - I was having lots of
problems with the rowing outriggers - Richard didn't want to use them -
no probs - but Peter wanted his boat to really whizz along and I
couldn't come up with a really neat solution.
The
other problem was I couldn't find space for the width of the front and
rear seats on the 4 sheets of ply.
Outriggers
 (Outriggers
and a sliding seat option have been dropped from the revised version)
'Riggers
are usually fabricated from either stainless steel tube or are part of
a drop-in one-piece sliding seat come outrigger arrangement like the
"Oarmaster" or the "Wing". Both are possible contenders for
this
boat, but they are pricey items costing much more than the materials
for the whole boat - so I had to come up with a wooden arrangement.
Eventually I worked it out - a simple frame to transmit the
loads
to plywood top and bottom faces. This will allow Peter
Hyndman
(and whoever else) to swing 9 or 10ft oars to really build the pace and
will add a trivial amount of weight to the boat.
There
will be two sets of rowlock holes. One when sitting at the
back
of the rowing seat when there is no passenger and one at the front, so
the rower can slide forward and keep the boat in reasonable balance.
Richard in particular is pretty adamant about this - one of his
current boats from another designer ONLY trims with a passenger in
place. Without the passenger it is badly out of balance so
digs its nose in and is a pain to
row.
Fitting
the panels onto the plywood - March 10
 Well,
now I'm back from visiting Peter Hyndman where I have been distracted
from working on the Rowboat plan by the Puddle Duck Racer Project.
Basically the Puddle Duck is the boat that should be the
entry
point for all sailors - it soaks up a mere three sheets of exterior ply
and costs a grand total of around $300 to get in the water -
including a sail made of polytarp. That is, once I do the
plans
for our super sleek, super strong and super light version that we came
up with during my visit.
But the Rowboat is the priority at the moment.
Anyway
back home I have now three people interested in the plan so have been
cracking my head to get it all to work.
One
of the
big problems has been fitting it on the four sheets of ply. I
KNEW
I could get it to fit OK on the 4 sheets but version 1 did not even
come close. The starting point is always a symmetrical layout
with the side panels mirrored across the long axis of the sheets.
But that narrow bit in the middle wasn't wide enough for any
of
the other pieces - and there was no room to fit the stern and bow
seats. It looked like this.
 Version
two (below) from early January was a bit better - but those big wide
seats were still not going to fit in no matter how I tried.
Not
having a symmetrical layout is not a problem. The
side panel
on the top sheet is still in the same form as the dimensioned drawing
so can be laid out without shuffling sheets. When it is cut
the
pieces become the templates to simply trace around to produce the
second side panel on the bottom two sheets.
Finally
it all falls into place, but it means I have to shuffle the panels into
a 3 sheet long arrangement. The whole thing doesn't have to
be
laid out at once (not everyone has 24ft of space to lay the three
sheets).
Lay out the leftmost two ply
sheets, mark and
cut the bottom panel. Pick up the leftmost sheet and lay out
the
rightmost sheet and mark out the side panel. When the side
panel
is cut it can be traced onto the remains of the ply to produce the
second side.
It did mean that I had to change the
dimensioned
drawings so the side panel could be measured from the opposite
side from
the drawings above - another 40 minutes of work to get that all
shipshape.
I
was quite happy with this layout - plenty of room for the bulkheads,
transom and enddeck/seats on the spare sheet and some room for the
rowing seat which will be a pedestal type (to allow the crew to move
forward when there is a passenger to keep the boat in trim). Also there
is not too much waste and the grain direction on each panel is right
for the aesthetics of the boat. I prefer the grain to run
horizontally across the bulkheads but run along the the boat in the
case of the sides, bottom and seat tops.
So that's
another problem resolved.
PHEW.
Next I have to complete the stem, bulkhead and transom
drawings -
all the structure that holds the sides and bottom in position and
stiffens the whole structure. One of the keynotes of my
designs
is doing this with an absolute minimum number of pieces of ply and then
holding it all together with a minumum number of pieces of timber.
Light, strong, stiff. Also I have to work out the
drawings
that will show the framing that needs to be fitted on the back and
front faces of the bulkheads
Bulkheads
- the structure across the boat - March 14
Some
boats just seem to fall together nicely - for such a simple boat this
one seems to be fighting me a bit.
I
use Hullform - an Australian developed hull design program that is
quite powerful for its cost. One of its capabilities is to
work
out how the plywood will actually wrap around the hull to a reasonable
degree of accuracy. Once the ply is wrapped round it is
possible
to work out the actual shapes of the bulkheads - the pieces of ply that
form the transom (back of the boat) as well as the vertical
faces
of the front and rear seats and the vertical faces of the rower's seat
in the middle.
Now if you assume that with a plywood
boat that
all the edges of the bulkheads are straight - you would be sort of
right. To explain why we have to go back to the part of the
process near the beginning when I used the program to work out the
shape of the bottom and sides.
The drawing below
shows the port side of the hull with the bow pointing up to
the left.
 The
top line from the top left sloping down to the right is the sheer line,
the one sort of parallel but below that is the chine and the one lower
still at the bottom border of the image is the centreline of the hull.
The lines on each panel represent the lines along which the
ply
panel is perfectly straight. They are called Ruling Lines and
if
you put a straight edge along any of them it will sit perfectly flat on
the plywood.
The dark lines are the approximate
positions of the forward and middle bulkheads.
The
bottom panel is the simplest - as it is totally flat across
the boat, all the ruling lines are parallel to the cross boat
direction. As all the bottoms of the bulkheads run in this
same
direction that edge will be dead straight too. (Experts will
see
a small defect in the bottom panel toward the stern, but I did get it
right at the time I worked out the bulkheads - honest!)
The
side
panel is much more complicated. As you can see the ruling
lines
are sort of parallel in the middle part of the boat and near the
transom, meaning that a bulkhead edge that contacts them will still run
in a similar direction so will be very close to flat.
Actually it
is within a couple of millimetres of dead flat - but if you can notice
a curve of a couple of millimetres in the 600mm width of the side
panel, then you are a better boatbuilder than I am! So the
bulkheads in the middle and back of the boat including the transom have
been drafted with straight sides.
The ruling lines
go crazy up
in the bow of the boat as they rush to meet up at the base of the stem.
If you look at the dark lines of the approximate bulkhead
position closest to the bow you can see that about 9 ruling lines cross
the sides of the bulkhead indicating that the edge of the bulkhead will
not even be close to straight.
This is a
lot easier in the software than to
explain, but you still need to understand the explanation to work out
which way to go if the computer comes up with several conflicting
ruling lines. You have to understand what is the best choice
and
also understand if there are errors causing the different options to
appear.
So the bulkhead
edges are not straight on
the sides for
the front seat bulkhead or for the rowing seat front
frame. And as
those bulkheads are quite small the curvature is quite pronounced -
leading to a lot of dimensioning in the drawings to lay out the curve
accurately In this case there is so much dimensioning in a
small
space that it took a few goes to come up with a scheme which I felt
that most people could use without getting confused.
 This
is one of the early trial dimensioning versions - note again all
drawings on this page are a little distorted to prevent them being
useful without buying the plans. There are three drawings of
each
bulkhead across the page. The top three are the front seat
bulkhead and the three at the bottom are the transom.
Leftmost
of the three will be the dimensioned drawing, the centre will show the
framing on the front of the bulkhead, the one on the right will show -
you guessed it - the framing on the back of the bulkhead.
The
MIDPOINT is purely a notation for me to remember that the framing
always goes on the narrower face of the bulkhead so is on the front of
the bulkeads above "MIDPOINT" and on the back of bulkheads below
"MIDPOINT" except for the transom where we want the outside face clear
of framing so it has to be moved to the inside face and cut oversize to
allow for the bevel on sides and bottoms.
The stem
is simply a
piece of wood that is cut at the right angle for the way the sheerline
meets at top and a different angle at the bottom for as the chines
converge with the bow at a narrower angle.
After
this it is time
to put together the timber list before moving onto the detail drawings
of the rowing seat and the outrigger wings (yep, Richard, I know you
won't fit outriggers in a month of Sundays (but you might when Peter
Hyndman goes whizzing past you at the Goolwa Wooden Boat Show in '07).
The
image below is of the total drawing that is being worked on.
I
am deeply happy this very drawn out bit of drawing is now over.
Looking forward to seeing one or two on the water.
Now
that's the good bit!
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