vital need seems to be a single
propulsive agency for progress on the surface and when submerged.

An interesting table showing the success of the convoy system is
herewith presented:

----------------------------------------------------------------------
| Convoy Atlantic convoys |No. of |No. of mer-|Losses in| P.C. |
| Homeward |convoys|chant ships| convoy | |
|-----------------------------|-------|-----------|---------|--------|
| North Atlantic | 306 | 5,416 | 40 | 0.74 |
| Gibraltar | 133 | 1,979 | 30 | 1.5 |
| West African ports | 105 | 944 | 6 | 0.64 |
| Rio de Janeiro | 22 | 307 | 1 | 0.32 |
| | ----- | --------- | ------- | ------ |
| Total | 566 | 8,646 | 77 | 0.89 |
| | | | | |
| Outward | | | | |
| Various sailings from | | | | |
| British ports | 508 | 7,110 | 45 | 0.63 |
| | | | | |
| Other convoys | | | | |
| Scandinavian (old system) | ... | 6,475 | 75 | 1.15 |
| Scandinavian (new system) | ... | 3,923 | 16 | 0.41 |
| French coal trade | ... | 37,221 | 53 | 0.14 |
| Local Mediterranean | ... | 10,275 | 127 | 1.24 |
| East Coast | ... | 12,122 | 40 | 0.33 |
| | ----- | --------- | ------- | ------ |
| Grand total | ... | 85,772 | 433 | 0.51 |
|====================================================================|
| STATEMENT OF SHIPS IN ORGANIZED ATLANTIC CONVOYS |
| July 26, 1917-October 5, 1918 |
| SHIPS |
|--------------------------------------------------------------------|
| | Homeward | Outward | Total |
| | bound | bound | |
|-----------------------------|-----------|-----------|--------------|
| Convoys | 539 | 488 | 1,027 |
| Sh