Dave Gerr - Boat Mechanical Systems Handbook-How to Design, Install, and Recognize Proper Systems in Boats

that seacocks be fitted on all through-hulls

from 12 inches (30 cm) above the waterline

and down, or from a height of^1 / 60 th of the

waterline length above the waterline and

down, whichever is greater.

Hose Clamps, Sea Strainers, and Sharing Seacocks

Double Stainless Hose

Clamps

Naturally, as we’ve discussed several times

throughout this book, you don’t want the

hoses coming loose. The hoses to the sea-

cock or through-hull should all be fastened

with two stainless hose clamps at each end,

as described in Chapter 4. A hose coming

adrift on an open 1^1 / 2 - inch (38 mm) seacock

makes a heck of a big leak!

Sea Strainers and Hull

Strainers

Seawater is referred to as raw water for good

reason. It contains not only salt but also

otherimpurities, from algae and seaweed to

plastic bags, sand, mud, fish eggs, grit, and

trash. It’s important to keep these impurities

out of the plumbing system. For this reason,

every sea suction should be fitted with a sea

strainer (a filter) just inboard of the seacock,

before the plumbing is led anywhere else.

It’s also a good idea to install an external

hull strainer or grate over the through-hull

opening.

Traditional hull filters or grates are bronze

scoops or round filters. (On scoops, the slotted

openings face forward.) These work well, but

they require you to unscrew or unbolt the grate

to access or clean the through-hull proper.

Companies like Groco offer hull strainers that

hinge open for easy cleaning (Figure 17-7).

PART SIX: PLUMBING SYSTEMS WITH NOTES ON FIRE SUPPRESSION

Figure 17-6.
Requirements for
seacock locations
on powerboats per
ABYC H-27

Figure 17-7. Hull strainers (Courtesy

Groco)