JEFF GILBERT DESIGN
Q&A
Answers to Queries re: Scarper
Flo (SF), 9.5m Gaff Cutter
I've received a gratifying amount of
mail on this newish tilt at an oldish concept. I'm answering all the queries that came via
the list here in a single posting. SF is a Blue water live-aboard Gaff Cutter for a couple
to grab their dog and leave for good!. SF is both affordable (WLL<30) &
owner-buildable (Ply on ply/ring frames, single hard chine.) NB. Query #1 covers plan
acquisition & my general philosophy in this area.
Query #1
>From Mike Stockstill, mkstocks@bellsouth.net ...
> https://mkstocks.tripod.com
> March 31, 2000
>Do you have any study plans available?
A: Study Plans are
available for $25 US... the cost is mainly in A3 Color Photocopies and US Airmail.
If interested air mail a money order to
Jeff Gilbert Design,
9 Birbai Place, Waramanga,
ACT 2611, Australia.
I'll send your package
the same day. You'll get some real nice pictures for your wall, even if you don't
build. You may be better off buying the full set of 30 pages of offsets and plans
for $US 50. Included are full 3-D offsets and full 2-D developed panels, all at 82
centers, so that you can position bulkheads to suit yourself. The warning, and
reason for the lowish price is this...
you are buying plans which will ultimately produce a good craft, but only with a fair bit
of input from you.....
I draw and computer run plans to the stage where an experienced builder could proceed, a
competent back yarder too. Even had I the time, I wouldn't have the inclination to go the
whole hog and write step-by-step manuals, as these construction techniques, sequences and
details have been written plentifully and so much better by others. For example, for
this kind of construction, I'd recommend Buehler's Backyard Boatbuilding:
https://www.georgebuehler.com/books.html
Other useful building
books:-
https://www.boatdesign.net/books/boatbuilding.htm
Query #2
>From: Peter & Polly Vanderwaart <pvanderw@optonline.net>
>March 29, 2000
> I want to ask you about the hull shape. Offhand, I don't remember
>seeing a v-bottom boat so deep forward and so shallow aft. The effect
>is somewhat exaggerated by the extended "mackerel's tail" run. What
>is your thinking, and how did you develop the shape?
A: My brother also
picked this up. I think there is a bit of a tendency to superimpose a Bristol CC over this
design. In fact there are more differences than similarities. Scarper carries a
large spread of sail, with the mast fairly forward, out of the full head-room area of the
accommodations.. Consequently I wanted a lot of forward flotation, and went
for it with the deeper forefoot. The forr'd 2/3 beneath the V-berth is dedicated to this
(about 30 cubic ft). I'm 6'3" tall and wanted galley headroom while retaining
an elegant sheer, low and upswept into a longish bowsprit. The only way to achieve this is
to go deep, in this case it shows up in the forefoot. Another reason is that the narrow
beam/fine entry -this gives the headroom (& adds speed) without a huge displacement
penalty. This kicks out a lot of lift at the bow..again the deep fore-foot compensates.
The long aft run...(incredibly, given the extent of accoms, this design works
at 27' 6" i.e. nearly 4ft cut off aft) I was after speed. and lowish wet area CF a
conventional long keeled cutter. The ballast (40% inside, u/floor) is taken care of in the
center third of the boat, & with the drop/ bilge keel combo taking over the
whole nature of the ship, the long keel is replaced by a much atrophied version,
which assists directional stability & protects both motor &
rudder. On the "Mackerel" tail, take a look at Zoe, by Daniel Z
Bombighter, a veritable Hot-Rod of a Gaff Cutter, and IMHO the "Classic Design
of the Century for Extremely Short Persons"! (see p.91 Aug 1999 Classic Boat Mag).
>The L-shaped board
is also the first that I can remember where the
>foot of the 'L' is allowed out of the centerboard case. I would worry
>that there could be trouble guiding it back into place, especially
>with a side load.
A: If its hard to haul
up because of lateral forces, it will be because you are hard on the wind and hence it
might be prudent to leave it down!(accidental fail-safe design!!?). Actually the boat is
heavily ballasted at 50%, of with the board only 10% of overall. There is no need to
deploy it in shoal areas, or be pulling it up and down like the Keystone Cops. There IS a
mistake in the dwg..the haul up cable should protrude from the tip not go through it from
the side. When hauling it up (use a long-handled crank onto drum) this will guide the tip
into the slot and she'll scrape on in after that.
The slot could have a
couple of 45deg lip guide plates to help it in. The tip itself would be ground to a
rocket nose cone shape. Both board & entry slot are heavily beveled, so that at
worst it would scrape along in like tight scissors. I'm happy to redraw the Drop
Keel Profile...this is, after all, an appendage. The plate profile from tip to aft upper
semi-circle about the axle could be changed to a constant inside curve which equalizes the
problem. Again, reshaping the board as a triangle with a tangent from the tip to the upper
semicircle about the axle would work fine but make access to one side of the Dinette a
real clamber. Another option is go rectangular..whack the tip off with oxy, then
throw more lift weights in the bilge (NB boards on Zoe).
Question
# 3
>From: Sidney L. Patin <sidney@s...>
>Mar 27, 2000 (message 404 BCC Archive)
>How much would she cost to build in a yard ....
A: These boats
are conventionally carvel on steamed frames, and so are very expensive. Chuck Paine's
Rockport 30, whilst an extraordinary boat in all respects, will set you back $450,000 US.
.............. https://www.chuckpaine.com/z30western.html
Because of the much simpler techniques in Scarper, (Stitch and Glue Ply on frames) you may
be able to have it built for under $100,000 US. sailaway. There are 30 footers on the
Market for less. But you know and I know, the only way to get a bargain here is to
avoid the huge Labor component you'll pay a yard. I.E. roll up your sleeves
and leave them that way for a long time!
>.....and can you
tell me who has already built your design (email
>addresses?)
A: In round figures,
the number built is zero. The level of interest is moderate, but steady.
>How much are the plans?
Cheap, with reason.
Please refer to Question 1 above.
>is there a way to
build the boat with a bit more beam than 8'4'' (that
>would be kind of skinny for a live aboard IMHO)? For something that
>length, I would be looking for a beam of about 10' or so, so my wife
>would have room for her grand piano. Ha ha.
A: Fair enough. I have
seen a custom cat design with a music room .. a Shuttleworth I think. You'll find most
Pilot Cutters are in fact 10ft wide. (On the other hand some Sydney, Australia
inner city Terrace houses are, incredibly, 8 feet wide. But they don't even float!)
Lyle Hess' definitive BCC has a 10' 1" beam on a LOD of 28' 3'' which gives a
relatively Tardis-like ratio of 2.8 to Scraper's slender 3.8. In Scarper I
deliberately sacrificed beam for gains in speed, stability, elegance and land
transportability, in that order. So naturally you can have ten foot beam, but you will add
considerable displacement due to the constraints forced on the design by the simplicity of
the single chine construction. You could control the displacement by cutting
the deadrise (and adversely affecting motion comfort). You would gain some form stability.
Like all design exercises, no changes are without consequence. Ask your wife to replace
her piano with a flute! Very peaceful, too.
I hope the above is of
assistance. I would be delighted to answer any further queries if you can handle the
delay!
Yours Sincerely
Jeff Gilbert
jgilbert@dynamite.com.au |
