Vol. V · No. 2Issue 23May–June 2026·Port Townsend, WA·Boat Haven, Shop 7·(360) 385-6211
BHWT
The Bilge & Tankage QuarterlyA Journal of Marine Wet Trades · Published by Boat Haven Wet Trades Co.
EST. 2021ISSN 2769-3104
Department · Shop Drawings

Three reference plates

p. 48

Reference plates drawn at the shop bench — the diagrams we re-draw most often, redrawn for this issue. Each plate is a working approximation, not a build document. For an as-built schematic for your boat, write to the editor.

Plate · 23.A · MSD-IIIType III Holding Tank Layout — 25-foot sailboat
DWL Head Raritan PHII Y-VALVE [PADLOCKED] 38 gal XLPE tank RONCO TT-2000 VENT & FILTER DECK PUMPOUT OVERBOARD T-H [NDZ: closed]
Routing Head → Y-valve → Tank inlet Vent 1" filtered, clamshell aft Discharge 1.5" Trident 101 Overboard padlocked in NDZ
Plate · 23.B · WMK-SKIDSpectra Newport 400C skid mount — Quimper-class hull
PORT LAZARETTE COOSA-BOARD BASE, BONDED TO LAZARETTE SOLE Boost 12V HP Pump Spectra Pearson ERS Energy Recovery Membrane (SW30-2540) SEA BRINE PRODUCT
Mounting Coosa-board base / G/Flex bond Routing Stacked vertically Membrane Filmtec SW30-2540, 40" Output 15 GPH @ 12 A / 12 V
Plate · 23.C · LAVACLavac vacuum-head schematic
HEAD COMPARTMENT — LAVAC Lavac bowl SEALED LID Henderson vac pump Tank VENT
Operation Sealed-lid + vacuum draw Pump Henderson (manual) Routing Bowl → pump → tank Note No raw water; vacuum draws
How to use these plates

The plates are working approximations — the diagrams we re-draw most often, at the shop bench, on the back of a Casey calendar page or on the chart-table whiteboard. They are not build documents and they are not intended as such. For an as-built schematic specific to your boat, write to the editor with your hull's make and length and we will dig the install report and send back the matching pages.

Plate 23.A is the standard Type III holding-tank layout we install on any sub-30-foot sailboat that does not require an overboard-discharge capability (or where the overboard is kept padlocked closed in the Puget Sound NDZ). The specific Y-valve is a Raritan three-way; the tank is the Ronco TT-2000 in 38 gal; the deck plate is the Perko 1283. See the F/V Cape Fox feature for the worked install in the same layout on a Bristol Bay gillnetter, and the MSD primer for the regulatory context.

Plate 23.B is the watermaker skid mount we built for S/V Orcas Lullaby on this issue's Spectra Newport 400C install. The Quimper-class hull reference is to a generalized small-aft-cockpit sailboat with a port lazarette; this layout works for any boat with a comparable lazarette geometry. Plate 23.C is the Lavac vacuum-head schematic we hand to any customer considering a Lavac install.