The remains of a plank-built boat were discovered by the Poznan Archaeological Museum expedition in ąad by the Warta river in October 1981. The wreck was found at about 1.5 m outside the fortification ring 1 m below the actual ground level.
The boat from ąad is the first wreck of a plank-built boat built on a T-shaped keel with the bottom and boards overlapping that was found distant inland. The wreck measuring 8.5 m in length and about 2 m in width was located parallel to the embankment line with its bow facing the east. Presently the wreck is reconstructed at the exhibition of the Polish Maritime Museum in Gdasńk.
There had been seven strakes to either side of the keel. All seven had survived in the starboard side, while only three strakes were preserved on the port side. The end of strake 6 on the port side was not nailed to the sternpost; instead it was scarfed to the fifth strake. The strakes were assembled in the lapstrake manner with a land of 4.5 - 5.5 cm wide, and fastened with treenails 1- - 1.2 cm in diameter. The wedged treenails were driven from outside at an interval of 8.5 - 9.5 cm.
The hood ends of the planks were fastened to the sternpost with iron nails. The strakes were made of two or more overlapped planks joined through scarfs secured with treenails. A total of 16 frames, numbered 1 through 16 from the stern to the bow, were preserved. They consisted of straight floor timbers with futtocks alternating with half-frames. No fastening was observed between futtocks and floor timbers. The floor timbers were fastened to the hull with pine treenails, one for each strake. The naturally curved half- frames were not fastened to every strake in the hull. No fastening was observed between frames and keel. On the average the spacing between frames was 40 - 46 cm.
The inner structure was reinforced by a birch stringer notched over the floor timbers. Some of the half-frames were set over the stringer which was notched at these joints. At the sheer strake the hull was reinforced by a rubbing strake made of ash wood (Fraxinus sp.). Three additional elements were fastened to the hull from the inside in the stern quarter . Made of naturally curved branches, the longer arm of each knee-like timber was fastened to the inner side of the hull, while the shorter arm extended over the sheer strake and the rubbing strake.
The vessel could have reached a length of 10.70 m and a breadth of 2.35 m.
In the first study concerning the artefact in question the determination of the region and century of the boat's origin is described as one of the most important issues of the investigation concept concerning the artefact from Lad. On the basis of the analysis of the boat's structure and interpretation of the entire finding it was indicated that the boat originated from the end of the medieval period - perhaps the 13th century. The boat age measurements taken by the Laboratory of the Physics Institute of the Silesian Technical University in Gliwice with the employment of the C-14 method gave slightly different results. The conventional radiocarbon age was determined as 1120+70 BP (GD-2230), and the calendar age as 970 AD or 900 AD where the final error in respect of each of the specified dates may be estimated as + 90 years. The results have been adopted in the literature concerning early medieval Slavonic boatbuilding.
In 1996 seven samples from the planks and the central keel part were taken for dendrochronological analyses. Following examinations carried out at the Dendrochronological Laboratory of the University of Mining and Metallurgy in Cracow the construction of the boat was determined to fall in the years following 1125 AD. The obtained growth ring sequence on the basis of the samples from the boat is 234 years old and represents the period of 891-1115 AD. The actual year of cutting the trees determined by the dendrochronological method is not included in the C-14 dating range.
The keel of the Lad boat was made entirely from one oak trunk and survived in the length of 7.2 m. The sample taken from the keel central part shows that the element was made from trunk pith parts. The Lad wreck keel was given a shape close to the letter T in such a way that the pith centre went centrally through a plane between the keel arms and beam.
The analysis of board cross sections visible during sample taking permitted determining another regularity. The examined planks taken from all strakes are turned with their pith parts towards the hull's outside and the external parts come under the overlap of the next strake. The probable reason for that is that the keel and the front and back parts of bottom planks are exposed to heavy friction over the bottom. The higher planks of the upper hull part are placed in the same way, the pith part turning inwards. It is because wood has the highest ability to bend in the outer parts of the mother trunk.
In order to determine the place of origin of the wood from which the boat was made the obtained average curve was compared with chronologies from southern, central and eastern Poland. The mentioned ring growth sequence from Lad shows the greatest similarity to regional chronologies from the area of Wroclaw (t=7.3) and Opole (t=5.9).
It is thus indicated that the wood used for building the boat is of Lower Silesia provenance. The boat must have been built inland, most probably in the area of Wroclaw.