A semi-rigid pneumatic boat (1) comprising: a rigid hull (2) defined by a rigid underwater hull (3) closed on the top by a rigid floor (4) and bordered on two sides by two pneumatic floats (5); a ballast (8) arranged in the rear part of the rigid hull (2) and pumping means for filling it with water or emptying it thereof; two pneumatic chambers (10) defined in the respective rear parts of the two floats (5) and pneumatically isolated from the rest of the floats; means (12, 13) for inflating and means (14) for deflating the rear chambers; the boat having no rear board; thus, by filling the ballast (8) and by deflating the rear chambers (10) the boat is nosed up, with its rear part submerged and a load (25) may be brought closer, against the floor (4), and then by emptying the ballast and re-inflating the chambers (10) the boat is set afloat, supporting the load (25).