Rusty the Junk - Hull

Rusty is built of steel.

The hull and keel are 4mm plate, and the deck and superstructure 3mm.

When we found her, she was a part finished hull, with no deck, superstructure or transom. The frames had been raised upside down on a strongback in a barn on a farm in Huntingdonshire.

When we transported Rusty to Southwold to begin our part of the project, we had her turned over by the crane operators. This requires someone who knows how to turn a boat, and competent crane operators, neither of which we had! When we arrived at Southwold, we had a space with a 6 legged cradle waiting, and a very competent crane operator to pick her off the lorry and put her in place.

With the assistance of Dick Baldwin a local fisherman and friend, we removed the strongback, cut it up and raised it to support a cover which stayed in place through most of the building. This is much easier said than done, and to this day we don't really know how Dick did it!

The man who started the project was a boilermaker, and had access to very large metal working equipment, so he had had the hull plates rolled to make a round bilge hull, which was beautifully fair.

The frames are made of 6mm plate cut and joined to the appropriate shapes. Stringers narrow steel beams that run the length of the boat. run across the frames Steel beams that are set vertically and run right around the inside of the boat. the length of the boat, approximately every foot. The plates lay upon the stringers and are welded to each other and to the stringers at about 4inch spaces on alternating sides of the stringer.

The plates had been welded to each other with a MIG Metal in Gas, probably now the commonest form of welding. Wire is fed from a gun into an arc. Gas is fed around the wire, to protect it from the atmosphere. welder, from the outside only. He had been attempting single pass full penetration welding - very, very difficult. It was impressive that he managed as much as he did, but it all needed to be re-done. We weren't aware of the shortcomings of his welding at that stage because we knew very little about it, but for the price he could almost not have welded it at all and it would still have been good value.

In the end the plates were re-welded from the inside to ensure the full penetration. To do this we had to cut the stringers at the seams, and re-weld them afterwards. All the welding that we did on Rusty was MAG More traditional than MIG welding, a stick coated in flux, is melted into an arc. The flux melts to form a slag that is removed. welding (stick as its more normally known). We were influenced in this by the fact that the companies in Lowestoft who build oil platforms do not allow MIG welding at all on their structures, because one can't get the same level of penetration.

Hull plates have to be stitch welded, because they are comparatively thin. This requires the welder to do about a 3inch run, then move to another part of the boat and do another run, waiting until the original run is cold before continuing it. This limits distortion in the plates, and means that the welder becomes very good at starting and stopping.

Another problem that we discovered later was that there were no drain holes in the stringers. This is trivial to do before the plating- essentially one runs a grinder vertically down the stringers to almost a third of their depth. After the hull has been plated it's extremely tricky, as it's difficult to get a drill that close to the hull plates.

The gunwale The join between the deck and the hull. on Rusty is a 2inch diameter steel pipe. This had to be bent around the top of the frames and welded in place. This stiffened her up quite a lot.

The transom The part of the hull right at the back. curve was designed so that a single sheet of steel could be laid over it and welded in place (yet another point for the 3d modeller).

The deck beams were cut from 6mm steel plate, welded across the tops of the frames and strengthened with knees. Again stringers were welded across the deck beams and the 3mm deck plates were welded to these.

The deck around the wheelhouse was edged with angle iron to provide the necessary stiffness. Then frames for the wheelhouse were raised from there. Roof beams supported with knees were welded across the tops of these and stringers across the beams. The wheelhouse walls are 3mm plate welded to the frames. The roof is 3mm plate welded to the roof stringers.

There are no stringers in the wheelhouse walls, because we wished to insert a lot of windows and it is not a major structural component of the boat. The wheelhouse windows are double glazed clamp on units from SeaGlaze. When fitting large windows like this it is very important that the plates haven't twisted at all when they are welded into place. The windows, being glass, can't tolerate more than a few millimetres deviation from a perfectly flat plane. Perspex is slightly more forgiving. Basically if the frames are all properly in line, there shouldn't be a problem. We had to re-make the forward port corner of the wheelhouse, as it had too big a curve. It was undetectable by eye, but far too much for the window to handle. These windows are very heavy, so it is best to make accurate templates and use those for all checking and offering up etc.

Hatches were set into the deck and the wheelhouse roof. These were Moonlight Hatches. Our friend Jan fashioned supports for them from angle iron, that could be welded into the deck. Then the hatches screwed to these supports. We nearly made a mistake positioning the hatch in the back deck. It was only because we simulated going in and out of the main hatch that we realised that it was too close. This wasn't as obvious as it sounds, as our main entry at that time was through the transom, and there was no companionway ladder.

At this stage the shell was complete.

Internal watertight bulkheads were added. One at the front approximately 10ft back from the bow and one each side of the engine room. The forward one enables us to close off the bow when at sea, to give emergency buoyancy at the front or to contain hull damage if we hit something. The one after the engine can close off the aft cabin for the same reasons. In addition the engine room can be sealed to stifle a fire.

The edges of entrances through decks, walls and bulkheads, were all supported by angle iron, to give them the necessary strength and stiffness. Around the main hatch these were stainless steel, as we thought the paint there was very likely to be chipped. We were right.

The deck in the aft cabin, the wheelhouse roof, and the deck in the saloon were all supported by stainless steel grab poles, because of the wide open spaces. We juggled their positions and the furniture so that they weren't in the way. In fact they have been more useful than obstructive.

Partners of steel were constructed where the two masts come through the deck. These were formed into octagons and welded into the deck, with a lot of strengthening. On a junk rig almost all the stress of sailing is transmitted to the deck at the partners. See the rig for more details.

A solid guard rail was fashioned from stainless steel. There was a stanchion The equivalent of a fence post for the guard rail. above the end of each frame, welded to a stainless steel plate that is in turn welded to the deck. The extra plate is so that the inevitable leaks into the hollow stanchions don't end up on mild steel, as there is no way to paint inside the stanchions. Cross bars were welded between the stanchions at half height and just above the deck. The lower one acts as a fairlead A smooth route for a mooring line. for mooring lines etc. At the top a stainless bar was welded all around, to which a teak rail could be fixed. Openings were constructed in the rail at the sides and the bow and stern. The stanchions either side of these were stiffened, with angled supports.

Mooring bollards Used to attach the mooring lines to the boat when she is tied up. were fashioned from stainless pipe, with a raised cap over the end and a bar just below the cap. We mounted these in pairs on each side fore and aft. In addition we mounted two single ones at the mid points on either side.

At the bow we implemented a twin roller system, for storing and deploying two anchors. This was a system that we had designed for Duet and had worked well. So we scaled it up a little and used it for Rusty. It is made from stainless steel, with a teak plank through the centre, to make it easier to get on and off at the bow.

We fashioned a pair of samson posts Very strong posts, for attaching the anchor chain when she is at anchor. from thick walled stainless pipe, again with a raised cap and a bar through. These were extended through the deck and welded to frames inside the hull.

At the stern we fitted a narrow bathing platform just above the waterline and steps up to the deck from there. These were made from stainless steel filled in with teak.

We designed a framework at the back to mount on the solid rail, this carries various gadgets, like a wind charger, a radar, the stern light and a hoisting point for the dinghy, although that latter didn't work out quite right.