A brief chronological summary of the types of anchors vryhof has designed
for use in the offshore and dredging industries:
• 1972 - The Stevin anchor: The original design. The wing was not yet
enlarged. The anchor had a square shank. It is no longer manufactured.
• 1974 - The Hook anchor: originally designed for permanent moorings.
This design was surpassed in 1980 by the Stevpris design and is no
longer manufactured.
• 1977 - The Stevin Mk3 anchor: is the improved version of the original
Stevin anchor. It was equipped with an enlarged crown and fluke
area and a streamlined shank for more efficient penetration. This
anchor is still manufactured and in use in offshore and dredging
activities. It has all classification societies approvals.
*1978 - The Stevfix anchor: this anchor was designed with special fluke
points for harder soils and a larger fluke area than the Stevin, but
has been surpassed by the Stevpris anchor. It is no longer manufactured.
• 1979 - The Stevmud anchor: the Stevmud is essentially the Stevin anchor
with a considerably enlarged fluke area. This anchor type was also
surpassed by the Stevpris anchor and is no longer manufactured.
• 1980 - The introduction of the Stevpris and Stevshark anchors. The
Stevpris anchor is a deep penetrating anchor with a plough shaped
shank, surpassing the performance of all earlier designs in the
vryhof range, and incorporating the latest experience, research
and knowledge of the anchor designer. The Stevshark anchor is a
specially reinforced Stevpris anchor, equipped with a serrated
shank and cutter-teeth for better penetration in hard soils, such as
coral types or sandstone. The fluke points are specially reinforced
to withstand high point loads.
*1990 - The Stevpris Mk5 and Stevshark Mk5 were introduced. The
improved versions of the original Stevpris and Stevshark anchors.
Improvements have concentrated on two features: higher holding
capacity and easier handling.
•1996 - Introduction of the Stevmanta VLA (Vertical Load Anchor). Based
on industry demand for an anchor that could withstand vertical
loads, the Stevmanta VLA was developed. The Stevmanta VLA is a
new design in which a traditionally rigid shank has been replaced
by a system of wires connected to a plate. The anchor is designed to
accept vertical (or normal) loads and is installed as a
conventional drag embedment anchor with a horizontal load to
the mudline to obtain the deepest penetration possible. By changing
the point of pulling at the anchor, vertical (or normal) loading
of the fluke is obtained thus mobilising the maximum possible soil
resistance. As a VLA is deeply embedded and always loaded in a
direction normal to the fluke, the load can be applied in any
direction. Consequently the anchor is ideal for taut-leg mooring
systems.
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