Smith-McIntyre grab sampler

Science Center Objects

The Smith-McIntyre grab sampler, nicknamed the Smith-Mac, scoops up sediment from any water depth.

Two women wearing personal protective gear on a boat stand near a mud sampling device and scoop mud from it.

PCMSC scientists Amy Foxgrover (left) and Leticia Hallas collect mud from a Smith-McIntyre grab sampler aboard R/V Parke Snavely to study sediment sources and redistribution within San Francisco Bay.


Grab samplers like the Smith-McIntyre, or “Smith-Mac,” easily scoop up sediment from the bottom of the ocean, bay, or lake—wherever bottom sediment samples are needed for research. Grab samplers are simple, robust, and reliable.

The impact of the Smith-Mac's foot plates on the seafloor triggers the release of heavy-duty springs that rapidly force the bucket jaws to clamp shut into the bottom sediment. This forceful, quick action ensures penetration even in stiff sediment. On retrieval, the lifting force of the wire closes the jaws and holds them tightly shut until the sampler is recovered to the deck.


  • Dimensions - 3’ x 3’ x 3’
  • Power Requirements - none
  • SWLs - 1,000 lbs.

Operational characteristics

  • Minimum Operational Depth - 5m
  • Maximum Operational Depth - unlimited
  • Sediment Type - Any
  • Limitations - Its light weight may limit penetration in dense sediment and may kite in deep waters
  • Power Outputs / Freq. Ranges - none
  • Ship’s Requirements
    • All overboarding gear rated to a SWL of 1,000 lbs.
    • A-frame or davit with 6’ of clearance.
    • Winch and wire/cable with approriate SWL and length in excess of planned water depth
    • Ability to hold station for duration of operation in variety of sea states

Additional equipment required

  • Stand for landing/subsampling
  • Trigger tensioning arm
  • Subsampling equipment and supplies, as needed

Complementary Systems

Often used with larger coring systems (jumbo piston corer, Rossfelder vibracorer) to determine site suitability or to obtain surface samples