Stainless Steel Sounding Head

Types and Materials

Sounding heads are classified by their mounting location and mechanism. The main types are:

Type A: For steel decks (inject head).

Type B: For wood decks (inject head).

Type C: Elevated or lift inject head.

Common material combinations for the body and cap include:

Body: Carbon Steel or Stainless Steel (316, 316L).

Cap/Plug: Stainless Steel or Brass.

Gasket: NBR (Nitrile Rubber)

Overview

Description and Function:

A sounding head, also known as a sounding pipe head or inject head, is a self-closing cap assembly welded onto a ship's deck. It provides a sealed access point for a sounding tape or rod to measure the depth of liquids (like water, oil, or ballast) in tanks below, while preventing water ingress and tank content escape.

Key features include:

• Self-Closing Mechanism: The cap automatically seals after the sounding operation to maintain tank integrity

• Corrosion Resistance: Stainless steel construction (often 316 or 316L) offers superior resistance to seawater and harsh marine environments

• Weldable Design: The base is designed for butt welding directly to steel decks

• Optional Chain: A plug chain can be attached to prevent the cap from being lost overboard

Specifications:

Parameter	Specification
Design Standard	CB/T3778-1999 (or JIS F3002)
Nominal Diameter (DN)	DN40 to DN150
Nominal Pressure	0.2 MPa or 0.3 MPa
Medium	Water, Oil
Connection	Butt Welding
Seal Test	0.11 MPa water pressure for 5 minutes
Thread	M453 to M1653

Dimensional Data:

N	H (Height)	D1 (Body OD)	D2 (Cover OD)	D3	D4	a	B	h	d (Thread)	D	D5	b	Weight (kg)
40	60	64	50	70	57	34	6	10	M45×3	90	59	6	0.96
50	65	76	62	82	76	34	6	10	M60×3	113	78	6	1.4
65	70	96	82	102	92	34	6	10	M76×3	125	94	6	1.82
80	75	109	93	115	106	55	10	14	M90×3	145	108	10	2.81
100	80	134	118	140	126	55	10	14	M115×3	170	128	10	4.62
150	100	188	172	194	178	55	10	14	M165×3	210	180	10	9.58