Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Convoy PQ 15
Table title:
Merchant ships
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Name </th><th colspan=1 rowspan=1 > Flag </th><th colspan=1 rowspan=1 > Tonnage (GRT) </th><th colspan=1 rowspan=1 > Notes </th></tr>
<tr> <td colspan=1 rowspan=1 > Alcoa Cadet (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 4,823 </td><td colspan=1 rowspan=1 > Lost in N.Russia after arrival </td></tr>
<tr> <td colspan=1 rowspan=1 > Alcoa Rambler (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,500 </td><td colspan=1 rowspan=1 > At Reykjavik 15-26 Apr </td></tr>
<tr> <td colspan=1 rowspan=1 > Bayou Chico (1920) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,401 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Botavon (1912) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 5,848 </td><td class="highlighted"  colspan=1 rowspan=1 > Torpedoed and sunk later by convoy escort Capt H J Anchor OBE RD RNR (Commodore) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Cape Corso (1929) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 3,807 </td><td class="highlighted"  colspan=1 rowspan=1 > Sunk by aircraft torpedo </td></tr>
<tr> <td colspan=1 rowspan=1 > Cape Race (1930) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 3,807 </td><td colspan=1 rowspan=1 > At Reykjavik 15-26 Apr Vice-Commodore </td></tr>
<tr> <td colspan=1 rowspan=1 > Capira (1920) </td><td colspan=1 rowspan=1 > Panama </td><td colspan=1 rowspan=1 > 5,625 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Deer Lodge (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 6,187 </td><td colspan=1 rowspan=1 > At Reykjavik 16-26 Apr </td></tr>
<tr> <td colspan=1 rowspan=1 > Empire Bard (1942) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 3,114 </td><td colspan=1 rowspan=1 > Joined From Reykjavik. Heavy-lift crane ship N Russia </td></tr>
<tr> <td colspan=1 rowspan=1 > Empire Morn (1941) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 7,092 </td><td colspan=1 rowspan=1 > CAM ship at Reykjavik 16-26 Apr </td></tr>
<tr> <td colspan=1 rowspan=1 > Expositor (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 4,959 </td><td colspan=1 rowspan=1 > Reykjavik 15-26 Apr </td></tr>
<tr> <td colspan=1 rowspan=1 > Francis Scott Key (1941) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 7,191 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Gray Ranger (1941) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 3,313 </td><td colspan=1 rowspan=1 > Detached, Arrived Lerwick 8 May Replenishment oiler </td></tr>
<tr> <td colspan=1 rowspan=1 > Hegira (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 7,588 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Jutland (1928) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 6,153 </td><td class="highlighted"  colspan=1 rowspan=1 > Bombed, Wreck Sunk By U-251 </td></tr>
<tr> <td colspan=1 rowspan=1 > Krassin (1917) </td><td colspan=1 rowspan=1 > Soviet Union </td><td colspan=1 rowspan=1 > 4,902 </td><td colspan=1 rowspan=1 > Icebreaker on passage </td></tr>
<tr> <td colspan=1 rowspan=1 > Lancaster (1918) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 7,516 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Montcalm (1904) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 1,432 </td><td colspan=1 rowspan=1 > Icebreaker on passage </td></tr>
<tr> <td colspan=1 rowspan=1 > Mormacrey (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,946 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Mormacrio (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,940 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Paul Luckenbach (1913) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 6,606 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Seattle Spirit (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,627 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Southgate (1926) </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 4,862 </td><td colspan=1 rowspan=1 > At Reykjavik 16-26 Apr </td></tr>
<tr> <td colspan=1 rowspan=1 > Texas (1919) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,638 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Topa Topa (1920) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 5,356 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Zebulon B Vance (1942) </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > 7,177 </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
How many Convoy PQ 15 ships were sunk?
Answer:
Three of PQ 15's ships were sunk: Botavon in 1912, Jutland in 1928, and Cape Corso in 1929.