Practical Boat Owner – August 2019

LEFT New bimini

created by Ann.

BELOW The finished

article on Aderyn

Glas

1

Place the original bimini right

side down onto the new canvas

and draw around it. With a white

chinagraph pencil, mark the centreline,

and the position of the Velcro and zip

channels and the backstay opening.

The width of most canvas and other

fabrics is between 140cm and

150cm. When taking measurements

I estimate in metres, and cut along

the length of the fabric. For example

if the sprayhood is 3.5m wide across

the cockpit then I would need a 3.5m

length of fabric to cover the cockpit

width, and as many pieces of cloth

as necessary for the cockpit length.

A sprayhood is typically made of

several different sections: the roof,

the front section with the windows,

and two side panels usually with

webbing straps. In a wide cockpit the

width of the roof section will take up

most of the width of the canvas so I

would not be able to get the window

section out of one piece. I’d need an

additional 3.5m of fabric.

I measured the canvas zip channels

and Velcro channels inside the old

sprayhood, which attach it to the

stainless steel frame and then the

side sections.

On squared paper I checked that

they could be cut from the spare

width material left from the window or

roof section. If so, 7m of canvas was

required for my sprayhood; if not, I

would calculate the extra length

required. When I’d worked out the

length and widths of all the major

pieces and their component parts I

added an extra metre or so to allow

for any errors in measuring.

Extra fabric can always be used on

smaller projects around the boat, and

as coloured canvas is dyed, another

batch might not be the same.

Edging material, Velcro, plastic

lining and webbing are measured

directly along their lengths and the

total length added up from each

major piece being made. Zips are

measured exactly, as they only come

in specific lengths and will need to be

shortened to fit if they are too long.

I always replace any plastic fittings

associated with the canvas work. If

the canvas stitching has degraded

then they will have too.

How much material

do you need?

required. Some popular brands are
Typical, Brother, Pfaff, Juki and Singer.
Machines can be researched through
ebay but your local industrial sewing
machine company would be a better bet
as servicing and backup would be part of
the package.
The main items I needed to replace on
Aderyn Glas were the dodgers,
sprayhood, bimini and bridging piece (this
stretches between the sprayhood and
bimini to from a solid canopy over the
cockpit when in port or anchored, so is
fully detachable).

2

Remove each zip and Velcro channel

from the old bimini after marking

their original positions. You can then

measure and compare between original

and new before you sew the new ones in

place. Take the detached pieces (eg, the

zip, seen above) and sketch the position

of the individual elements (such as the zip

open and closed ends). Draw around these

individual pieces on the new canvas.

3

Amazingly, all eight elements at the

bottom of this photo are needed to

make the rear starboard zip channel and

back flap of the bimini (the original three

pieces at the top). Once sewn back

together (see steps below) you’ll need to

repeat the process for the other two roof

zip channels, and the port side flap and

zip channel.

Accurate measurement is essential. To

ensure that every part of the bimini

would match up I drew in permanent ink

on the old canvas to identify where each

element fitted but transferred marks to

the new canvas with a white chinagraph

pencil which would rub off later.

I used the individual pieces of the

bimini, once deconstructed, to draw

around and copy the image directly onto

the new canvas. I took care to flatten out

or straighten out each individual piece.

Curved pieces when flattened out take

up a greater length. The bimini has three

zipped channels, one central Velcro

channel and a Velcro back flap to go

around the back stay. This design also

has a zip inserted along the whole front

face to link to my bridging piece.

When you transfer dimensions from old

to new material it’s best to work from a

datum. In my case I established a centre

line on each piece and worked from there.

DIY CANVAS WORK

Recreating the bimini