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Been a little bored recently and so I decided to make an offshore style drag anchor for the future tug I will be building. I originally wanted to make the anchor from brass but I was stuck for a way to cut out the 1.2mm thick sheet. I then decided to try with plasticard.

The plans I have drawn up for the anchor are here

I was inspired by this photograph and memories of my offshore career where I was around these anchors quite a lot.

First things first, I looked on the internet for some basic measurements and put the data into CAD and drew the anchor full size. This was then scaled down at the printer which is the usual way things happen with CAD.

Some basic paper plans were printed and stuck together to see how the anchor would look.

There was a few areas I was unhappy with which were then changed in CAD and again the design was printed out and roughly assembled. Once I was happy, the plans were printed. As you can see by the top two sheets, I was playing about with the angles of the sides.

The parts were then cut out and stuck onto 2mm plasticard with pritstick. The adhesion didn't last long but it was enough time for me to score the outer and inner edges with a knife. They were then simply snapped off leaving a good clean edge.

The base of the anchor was then scored about a quarter of the way through and snapped along the edge, being careful not to completely snap off the parts.

The profile of the base was then decided with use of a tin and a cheque book! This was about 13mm from the base to the underside of the base. I then used my trusty plasticard filler made from plasticard melted into a bottle containing a few drops of plastic weld. The mixture is perfected until like a thick syrup. Ive found if its not potent enough (runny), then it will cure before it gets chance to eat into the parent material of which I am filling.

The filler was then left for around 3 hours to ensure it had completely hardend.

The sides were then scored in the appropriate places and a washer added with a 3mm centre hole. When painted or wethered, this will beef up the hole as it will be used to drag, handle and lift the anchor when on the ships deck. The hole was then made using a 3mm drill bit.

The filler has been left to cure and then it was all sanded down flush with the parent material. The joint now is basically as strong as the parent material and it has acted like a proper metal weld. The parts could be separated, the edged bevelled and then plastic welded together, however I personally would manage to make it wonky given the fact I usually make a blunder while building something.

These are the brackets in which the real anchor would lock onto its base. Again everything on the anchor is 2mm plasticard.

Here the sides have been installed with most of the brackets (they are located either side of the sides), and the cross strengthener piece was installed.

While this was curing, I knocked up a basic shackle. Its 3.2mm brass rod cross drilled with 2mm holes and bent round a 6.5mm drill bit.

The end strengthener peice was installed. 2mm diameter threaded rod was then installed and secured with nuts to complete the shackle.

All areas needing filler were filled and sanded flush. It looks a mess but its actually very smooth!

This is the configuration in which the anchor its normally pulled on deck.

All that remains is to install more 2mm threaded rod through the brackets and again secure with nuts, this will be done when I have decided what to do in regard to giving the anchor some colour. These anchors have the facility where its pitch can be changed to suit the type of sea bed, i.e sand, rock or clay etc... This anchor could be made to change pitch quite easily by making a slot in the base in which the forward parts of the sides can slot into, as the rear brackets are fixed hinge points. This picture also shows the middle strengthener peice.

Got hold of some chain, infact two types of the same size, one brass and one steel nickel plated.

The chain attached to anchor.

There are several types of chaser. This being a ring or permanent chaser. The general idea is that the anchor chain is fed through this and then shackled to the anchor. The other end of the chain is obviously connected to the vessel or platform. When the anchor is first taken off the vessel or platform, it would be lowered onto an anchor handling tug via crane anlong with the chaser and wire which will be attached to it. The anchor will be then dropped at a specified location and the chaser wire at this time will be attached to a bouy. So when the anchor needs to be retrieved, the chaser wire will be connected to the anchor handlers winch and hauled.

It is 3.2mm brass rod which has been bent, copper braised and had some normal solder applied to the joint to pad it out and to make the join look uniform. It will be cut down to size later and cross drilled.

General idea of how it would look when hauled onto the anchor handlers deck.

 

 

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©Dan Walker