ABSTRACT A new type anchor what is called DA-l was experimented。 Model experiment was executed at the Anchor Model Basin in the Faculty of Marine Technology, Tokyo University of Marine Science and Technology。 This result was compared with JIS type and AC-14 type。 In the case of horizontal pulling experiment, AC-14 anchor showed the highest holding power among three types of anchors, but the continuity of high performance was not so good as DA- l anchor。 In this experiment authors could show the high performance of a new type (DA-1) anchor concerning the sustainability of high holding power。 The reason of this result is depends on overturning performance of anchors。 AC-14 anchor is overturning more easily than DA-l anchor。 At the comparison of towing direction of horizontal pulling experiment, 180 degree pulling direction was not so good performance as normal pulling direction。 At the 180 degree pulling, angle of fluke of anchor is not fully developed by the sand in the hinge of anchor。 The effect of transverse inclination of bottom surface was also experimented。 The performance of holding power decreased compared to the flat bottom。82149

1。Model Anchors

3 types of model anchor was experimented in the anchor model basin of Faculty of Marine Technology, Tokyo University of Marine Science and Technology。 These are JIS type,  AC-14  type  and  DA- l  type  as shown in Fig。1。

Fig。 2 show also the difference of anchor crown of these 3 types。 The dimensions of these experimented anchors are shown in Table 1。 In this table, length means the maximum length parallel to the anchor shank and width means the maximum length right-angled to the anchor shank。

Fig。1 Model Anchor   CHS (left), AC-14(middle), DA-1(right))

Fig。2 Anchor  Crown of 3 Types of Anchor  ( JIS type (Left), AC-14 type (Middle), DA-I  type (Left)  )

Table 1  Dimensions of Experimented Anchors

Anchor type Weight (kg) Length论文网

Width (mm)

JIS type 11。0 394 245

AC-14 type 10。0 430 320

DA- l type 9。8 405 330

DA-I type 16。0 475 397

2。Experimental Facility and Experimental Conditions

Anchor Model Basin is shown in Fig。3。 This figure shows the condition of horizontally towing。 In Fig。4 shows the condition of 20 degrees’ towing。 Initial towing direction is not only Odegree but also 90 degrees and 180 degrees。 These condition shows in Fig。 5。 Fig。6 shows the condition of the transverse inclination of bottom surface。 Fig。7 shows the example of experimental result。 Authors analyzed on the maximum resistance force。 This figure is not actual result, but shows typical pattern of the holding resistance force。

Fig。3 Experimental Facility (condition 1, pulling angle 0°)

Carriage

-  Load  0elI

Sand

Digital Recorder

lira  Rope  and Chain

Fig。4 Experimental  Facility (condition 2, pulling angle   20°)

(a)90 degree (b)  180 degree

Fig。5