This website aims to bring together all available information and photographs concerning TID class tugs. If you have more information, stories, pictures, experience of working on TID tugs or can correct anything within the website, please contact Martin Stevens.


The TID Story - "One Tug Per Week"

In 1943 the Ministry of War Transport decided to introduce a new class of tug. Urgent demands were made for small tugs for harbour and dock work, and to support the impending invasion preparations. The terse statement made to satisfy the needs was simple:

"Design, organise and start work immediately toward achieving, in the shortest possible time, the delivery of one tug per week, using in the process, little or no shipyard labour."

Constructional engineering yards were already hard-pressed and could not accept orders for tugs, generally launched from conventional slipways. However, there was more capacity in manufacturing establishments for welded work rather than riveted work. For instance, railway train manufacturers were not in demand so perhaps they could be used for producing these tugs. It was evident that the planning must allow for work to be placed with a number of different firms, and the basic design for an all-welded tug emerged.


Technical Innovation

Pre-fabricated construction in shipbuilding had risen to huge proportions in the United States but there was little, if any, in Britain. Now, however, its possibilities were investigated, with a tank-tested model requiring only minor modifications before acceptance.

The result was a complete departure from normal British shipbuilding practice, in shape, in design detail and in the construction of pre-fabricated parts for the assembly of a vessel - welded, not riveted. It was an advance in technical and industrial development.

So came the "TID" tug. It was to be mass-produced and of straight-line form. The hull was designed on the 'hard chine' principle, all design lines of the same strake of plate being parallel, giving frames in straight lengths. There were to be no bent frames, and curvature in the shell would apply in one direction only, i.e., with no twist in the plates.

The design was subdivided to eight units, cut right across the vessel, with all joints of units arranged to come midway between two frames. There were independent drawings for each unit, with the unit sizes restricted to maximums of 10 ft length, 17 ft width, 13 ft depth and a weight of six tons for transport by road, sometimes up to distances of 200 miles.


The eight sections of the TID

click drawing for general arrangement plan



Initially, contracts for making the units were awarded to

William Neill Ltd.
Foster Yates and Thom,
R.Dempster and Sons,
Charles Roberts and Co. Ltd.,
Newton Chambers and Co. Ltd.

The original order was for twelve tugs to be constructed, but when this was increased to fifty, Dunstons allocated the work so that two companies were responsible for making each section. This meant that supplies were assured if enemy bombing put one company out of business.

Unit One, the stern, a 4ft 2" section was made by Robert Jenkins and Co., also Foster Yates and Thom.
Unit Two, the aft peak tank, 10 ft, was made by A.J.Riley and Son, also Foster Yates and Thom.
Unit Three, the after cabin, 8ft 4", was made by Nortons Tividale Ltd., also Robert Dempster and Sons.
Unit Four, the engine room, 10ft., was made by Wrights Forge and Engineering Co., also Robert Dempster & Son. It is known that with such a prefabricated system, the bedding of the engine and alignment of the propeller shaft were difficult, and Robert Dempster and Son were trusted with this area from the outset.
Unit Five, boiler room and bunkers, another 10ft. section, was made by John Booth and Sons (Bolton), also Newton Chambers and Co. Ltd..
Unit Six, boiler room and bridge, 8ft 4", was made by Head Wrightson and Co., also Charles Roberts and Co. Ltd..
Unit Seven, forward cabin, a 10ft section, was made by C. and W. Walker Ltd., also William Neill and Sons.
Unit Eight, the bow section (incorporating the chain locker and fore peak), a 9ft 2" unit, involved the most difficult shaping, It was made by Orthostyle Ltd., also William Neill and Sons.



Welded by Women

The longitudinal seams of plates were left unwelded for a length of 10 inches at either side of a joint, in order that the plates might be 'sprung' together if any slight deviation from the correct dimension occurred. Each separate unit was completed with many of its fittings in position: a special feature of the after-most unit being that it was completed with the rudder, propeller and tailshaft in place.

At fitting-out stage - after completion and launch of the hull - the engine bedplate chocks were machined to dimensions taken from the engine after it had been packed and wedged up in alignment with the tailshaft.

The White TID - from a promotional brochure

However, with some fittings - namely engine room valves, pipework and auxiliaries - it was deemed unwise to have these fitted to the units by the sub-contractors, due to possible movement by vibration during transit. Therefore, such items were fitted at the shipyard, prior to the transverse all-round welding which turned eight separate units into a complete tug. Many women welders were involved in the construction of TIDs. At the end of the war, after pressure from the Trade Unions, they were all sacked.


Made in Thorne, Hessle, and Sunderland

Hull measurements of the tug were 65 ft length (bp), 74 ft (oa), 17 ft breadth and 8 ft depth, giving 54 gross tons. The draught was 7.3 ft with bunkers and water tank full. Full displacement was 124 tons, bollard pull two tons and full bunker capacity eight tons (coal) or nine tons (oil).

Assembly of the hull was done by Richard Dunston Ltd., at their Thorne shipyard, (who later took over Henry Scarr Ltd. of Hessle), in Yorkshire and late in the programme, to keep up with demand, by William Pickersgill & Sons Ltd., at Southwick, Sunderland.

A hull was put together every five days - the record was four.
The boiler, the two-cylinder compound engine, which developed 220 indicated horse power, and superstructure were fitted after the launching. For this purpose, units Nos. 4, 5 and 6 had their upper casings merely tack-welded into position by the contractors. These were removed by cutting the tacks and were easily replaced afterwards.


click drawing for larger version


'Springing' the section joins prior to welding

TID Relay

At Dunston's, the first TID was towed from Thorne to Hessle, her engine and boiler were fitted, ran trials back to Thorne and as she left for delivery towed the next completed hull downstream for its machinery installation. This went on week after week, each completed TID towing the next one.

During the four years of TID building, their appearance changed little, only minor changes to the deckhouse, boiler room and accommodation being made, most of these on the Sunderland-built craft. All TID's were built with an open bridge, so subsequent enclosed wheelhouses tended to be of individual designs.

The initial order from the Ministry of War Transport for twelve TID tugs quickly became twenty five; then, as production began, was altered to fifty, and as work quickly progressed the figure was doubled to 100. All were ordered as coal burners, to give 7-8 knots and with the liberation of Europe in mind, the main intention was for their use in smaller ports and anchorages.


TIDs Abroad

Then came the likelihood of the use of TID tugs in the Mediterranean and the Far East and another fifty were ordered. It was necessary to modify the design to make them burn oil. This was due to the lack of coal - or its generally poor quality - at prospective bases, and to give increased range to the vessels.

TID 132 on service in the Far East

Such conversion, including lowering funnels, required only slight structural modifications to two of the eight prefabricated units. At the same time it was decided to convert similarly the second batch of fifty tugs ordered, but with these already in production it was found possible to change only ten of them to oil. Finally, a group of thirty two oil-burners for tropical service was built, with generators to operate a boiler room ventilator fan and electric lights, and equipped with canvas awnings.