This paper aims to contribute to highlight the main factors which determine the commercial success of Short-Sea-Shipping lines. As a part of complex topic of modal competition, we will focus on the ship's performances. The finality is to define the capacities and the speeds needed by ships for compete effectively with the services "all-by-road" of freight transport in West Europe. In fact, the flexibility is the main competitive advantage of road transport over the other modes as maritime, fluvial or railways, and the travel time is the second one. With exception of some cases which have ports as origin and destination, the transport “Door-to-Door” needs the participation of road transport ineluctably. So, the modal competition between the Short-Sea-Shipping and the road transport is in fact a problem of their complementarily. The really important matter is how to maximize the Short-Sea-Shipping' component into the travels which combine the maritime and the road transports. The main impediments for the SSS's component maximisation are the travel time of the boats and the ports passage time.In continuity of our precedent researches, we use the results showing the more competitive SSS's lines (Martell Flores, 2007). On this base, we proposed the links between ports and the best operation way for each one, in “classical lines” of collecting & distribution or as "shuttle lines". All lines initially proposed are competitive with road transport under the costs criterion, but not always, even rarely, under the travel time criterion. We take the travel time by road as reference to define the travel time that the ships need to reach in order to be competitive. So, this analysis includes the cost & the travel time as criteria of comparison. We analyzed a network of the main 112 cities in West Europe, including 57 ports, which constitute our O-D matrix. For this analyse we use the DETCCM algorithm, it identified the differences between travel times of transports in “all-by-road” and in combined “maritime / road” for each possible link of the O-D matrix. The results show us a selected number of SSS's lines which are competitive in the current conditions of travel time. They show us the average speeds' necessaries to reach the competitive travel times for the rest of the lines. Finally, we made a performances’ review of the more currents ships in order to propose the more adapted kind of ship to the SSS proposed lines. The results underline the necessity to make new naval engineering developments oriented to design a specific Short-Sea-Shipping' boat in the close future.