Sketchbook: Cutting Patterns Accurately

Author:
Publish date:
Updated on
A. Because the interior dimensions on a boat are rarely straight, whenever you are thinking about adding a small locker or bulkhead you must measure, cut and trim the panels very carefully. Make sure the boat is horizontal so you can use a spirit level, along with an integrated laser, to project datums across the boat. Once you establish a fixed datum point, transfer as many measurements as possible to a pattern made of cardboard or hardboard. After cutting the pattern, put it in place and make sure it fits correctly before you start to cut the actual pieces of wood or plywood.

A. Because the interior dimensions on a boat are rarely straight, whenever you are thinking about adding a small locker or bulkhead you must measure, cut and trim the panels very carefully.Make sure the boat is horizontal so you can use a spirit level, along with an integrated laser, to project datums across the boat. Once you establish a fixed datum point, transfer as many measurements as possible to a pattern made of cardboard or hardboard. After cutting the pattern, put it in place and make sure it fits correctly before you start to cut the actual pieces of wood or plywood.

B. It’s easier to take internal measurements with two sticks held in your hand, or take a piece of plastic conduit with a snap-on top that slides with a stiff action that holds it in place.

B. It’s easier to take internal measurements with two sticks held in your hand, or take a piece of plastic conduit with a snap-on top that slides with a stiff action that holds it in place.

C. Transfer awkward shapes either with a profile gauge (which is like a comb with movable teeth) or by scribing around the shape with a compass held at a fixed angle.

C. Transfer awkward shapes either with a profile gauge (which is like a comb with movable teeth) or by scribing around the shape with a compass held at a fixed angle.

clamped a board in position, run the block over the relevant lumps and bumps and mark the corner positions as you go. Remove the board and use the spiling block to transfer the marks to a pattern. Having a long and short edge on the block makes life easier—but number the corners so you don’t forget which edge is which! E. When cutting a panel, measure the widest point to allow for any tapering; make a vertical cutout shape if you are going to have to slide the panel in vertically.

D. A spiling block can do a similar job. After you have clamped a board in position, run the block over the relevant lumps and bumps and mark the corner positions as you go. Remove the board and use the spiling block to transfer the marks to a pattern. Having a long and short edge on the block makes life easier—but number the corners so you don’t forget which edge is which! E. When cutting a panel, measure the widest point to allow for any tapering; make a vertical cutout shape if you are going to have to slide the panel in vertically. E. When cutting a panel, measure the widest point to allow for any tapering; make a vertical cutout shape if you are going to have to slide the panel in vertically.

F. A spokeshave is ideal for inside curves and shaping bumps and tapers, but it must be razor sharp to deal with all the end grain in plywood. G. For measuring bigger areas use a pointed stick with notches in it. Mark the notched positions on a board and use the stick again to transfer the shape on to a pattern board. A pattern board will also show whether you can get the full-sized panel in through the hatch!

F. A spokeshave is ideal for inside curves and shaping bumps and tapers, but it must be razor sharp to deal with all the end grain in plywood.G. For measuring bigger areas use a pointed stick with notches in it. Mark the notched positions on a board and use the stick again to transfer the shape on to a pattern board. A pattern board will also show whether you can get the full-sized panel in through the hatch!

Dick Everitt has been an illustrator, journalist and engineer for over 40 years. He has sailed many thousands of miles on all sorts of craft in various parts of the world

Related

20190614_131026

Kiwi Spirit Takes Line Honors in Bermuda

Mark Riley’s Farr 63 Kiwi Spirit secured line honors yesterday in the Marion to Bermuda race, finishing off St. David’s Lighthouse at 0227 local time. Francis Seldorff’s Kinship, a Baltic 52, was second in the 40-boat fleet, crossing the line at around 0500. With 18-year-old ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com No cracked skulls please Modern boats with aft bathing ladders offer a big advantage when it comes to rescuing crew who have fallen overboard. Not all casualties are basket cases unable to help ...read more

01-Lead-show

France’s Annual Multihull Show

If a boat show could be described as intimate, the annual Salon International du Multicoque in La Grande Motte, on France’s Mediterranean coast, is it. Held in the latter part of April, the multihulls-only in-water show is a boon for builders, because the people who attend come ...read more

Furlex-Electric

Gear: Seldén’s Furlex Electric

Furl Power Seldén’s Furlex Electric offers an easy path into the world of sweat-free headsail furling. The compact unit can be retrofitted to an existing manual Furlex unit or installed as a replacement for whatever you’ve got now. Its DC-DC converter accepts your boat’s 12V or ...read more

11_DSC8423Tom-Zydler

Cruising: Nova Scotia

There’s a unique cruising ground that combines access to urban locations with easy escapes to wilderness and nature. Its native people may be the friendliest on the east coast of North America. Its coastline runs 250 nautical miles in a straight line, but that should be ...read more

01-LEAD-shutterstock_727849660

Boat Monitoring System

Boat Oversight In a world where you can track your friends’ locations in real time and stream yourself live on the internet, it should come as no surprise that you can also keep a close eye on your boat from the comfort of home. In fact, not only is there a plethora of options ...read more