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Trireme Rowing Geometry, 6th Century B.C. (Time-Life Books: The Ancient Mariners, Page 71)

Sunday, October 9, 2016

Hatches...


Hatches… coverings for holes in the deck and bulkheads in order to keep water out, yet provide access. There are many commercial hatches available or you can make your own.

Commercial Hatches


Duckworks sells many hatches and deckplates:

  • Rectangular Bulkhead Access Doors
  • Deckplates that are pull-up style (with an integrated toggle), pry-up (with a screwdriver), screw–out  (typically a quarter turn to remove), and others that are semi-permanent (screwed down)
  • Round and oval kayak hatches using flexible material that snaps over a permanently installed base
  • Screw-out hatches that have an integrated bag on the inside for holding small items.
  • Sizes vary from 4” (102mm) (opening) to 8”… The access doors come in a variety of sizes.

Commercial Hatch Kits


Ashlyn and Russell Brown of Port Townsend Watercraft (PTW) sell flush hatches kits such as these.

PTW Flush Hatch Installed

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Chesapeake Light Craft sell flush hatch kits very similar to those of PTW.

Make Your Own Hatches


Russel Brown (of PTW) also has a very complete set of instructions for how to install his hatch kits. These instructions can also be used to make your own hatches, which is what John Welsford does for his boats.

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Sven Yrvind makes his own hatches.

Sven Yrvind's Hatches, Gluing the Frames

And Installing the Gaskets

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A “how-to” article on building a Griffith Hatch

Plans for a Griffith Hatch

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Jim Michalak’s article on how he makes hatches for his boats.

Plans for a Michalak Hatch

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The “Simplicity Boats” site (see “Boat Camping Ideas >> Big sleep space in small boats”) contains this method for making inexpensive hatches.
“Cheap hatch idea:  At a local pool cleaning company, they gave me (for
free) some 6 (23 L) and 12 gallon buckets that have locking screw top lids.
The 6 gallon buckets have a 12" (305mm) diameter, and the 12 gallon buckets have
a 15" (381mm) diameter.  Cut 3-4" (76-102 mm) off the top of the bucket and mount it
to the bulkhead, screw the top on and presto, a cheap water tight hatch.”

Methods for Holding Down Hatches 


This article in the Chesapeake Light Craft site shows how to hold down hatches from inside the compartment.

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Here are some other methods:





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Sven Yrvind uses the method illustrated below for securely tying down his hatches.

An Off-center Lever Tensions a Dyneema Line to Hold Down the Hatch 


Advice from Colin Angus on Hatches for Rough Water



From Angus adventure handbook (under “Introduction to Ocean Rowing >> Equipment >> Hatches”)

"All entrances to storage compartments or the cabin must be sealable using good-quality hatches.  The entrances of the main cabin and the ventilation hatch should be transparent to let light through and to offer visibility.  Lewmar makes excellent-quality aluminum framed hatches with Plexiglas panels. Hatch prices are exorbitant but unavoidable.  The cost of hatches for a new boat can be $4000 or more. 
Choosing appropriate round hatches for deck locker access is crucial.  The deck area is constantly awash, and if low-quality hatches are used, you will pay the price later.  The Whale Henderson TCL4 Hatch works well.  The lid is made from two pieces – the outer threaded ring which pivots around the stationary centre cap and O-ring. 
Important: Never use deck hatches where the lid is made from just one part.  These lids twist and contort the O-ring when they are being screwed down.  Some rowers, trying to save money, have used these hatches with disastrous results. 
All fittings on a boat, including hatch bases should be bolted on and never screwed. Bolts should be backed with adequate washers or plates. Caulking techniques are essential, and follow precisely instructions provided. 
Testing Hatches:  Inspect all gaskets and O-rings on hatches for signs of decay or damage, and replace if necessary.  Also examine the connecting surfaces for dings or distortion.  And finally, and very importantly, seal your entire boat and fire a high-pressure water hose over the entire structure and on the joining surfaces of all hatches. Any leaks should be remedied." 
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Let us know of other ways you use to securely close deck and bulkhead openings… ways that are waterproof and yet provide easy access.

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