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:
Submerged floating tunnel
Table title:
Proposals
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Date </th><th colspan=1 rowspan=1 > Place </th><th colspan=1 rowspan=1 > Country </th><th colspan=1 rowspan=1 > Proposer </th><th colspan=1 rowspan=1 > link </th></tr>
<tr> <td colspan=1 rowspan=1 > 1886 </td><td colspan=1 rowspan=1 > Patent N.9558 </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > Sir Edward James Reed </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 1923 </td><td class="highlighted"  colspan=1 rowspan=1 > Patent </td><td class="highlighted"  colspan=1 rowspan=1 > Norway </td><td class="highlighted"  colspan=1 rowspan=1 > Trygve Olsen </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 1947 </td><td class="highlighted"  colspan=1 rowspan=1 > patent pending nr. 91699 </td><td class="highlighted"  colspan=1 rowspan=1 > Norway </td><td class="highlighted"  colspan=1 rowspan=1 > Erik Ødegård </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 1969 </td><td colspan=1 rowspan=1 > Strait of Messina </td><td colspan=1 rowspan=1 > Italy </td><td colspan=1 rowspan=1 > Alan Grant </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 1998 </td><td colspan=1 rowspan=1 > Høgsfjorden </td><td colspan=1 rowspan=1 > Norway </td><td colspan=1 rowspan=1 > Norwegian Public Roads Administration </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > April 16, 2003 </td><td colspan=1 rowspan=1 > Transatlantic tunnel </td><td colspan=1 rowspan=1 > N/A </td><td colspan=1 rowspan=1 > Discovery Channel's Extreme Engineering (Season 1, episode 3) </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2011 </td><td colspan=1 rowspan=1 > Sognefjord </td><td colspan=1 rowspan=1 > Norway </td><td colspan=1 rowspan=1 > Norwegian Public Road Administration </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2016 </td><td colspan=1 rowspan=1 > Bjørnafjord </td><td colspan=1 rowspan=1 > Norway </td><td colspan=1 rowspan=1 > Norwegian Public Road Administration </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > June 6, 2017 </td><td colspan=1 rowspan=1 > Multiple potential sites </td><td colspan=1 rowspan=1 > N/A </td><td colspan=1 rowspan=1 > Hyperloop One </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > ? </td><td colspan=1 rowspan=1 > Funka Bay, Hokkaido </td><td colspan=1 rowspan=1 > Japan </td><td colspan=1 rowspan=1 > Society of Submerged Floating Tunnel Technology </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > ? </td><td colspan=1 rowspan=1 > Lake Washington, Seattle </td><td colspan=1 rowspan=1 > United States </td><td colspan=1 rowspan=1 > James Felch / Subterra, Inc. </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > ? </td><td colspan=1 rowspan=1 > Vancouver Island </td><td colspan=1 rowspan=1 > Canada </td><td colspan=1 rowspan=1 > Ministry of Transportation of British Columbia, Canada </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > ? </td><td colspan=1 rowspan=1 > Lugano Lake </td><td colspan=1 rowspan=1 > Switzerland </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Cook Strait </td><td colspan=1 rowspan=1 > New Zealand </td><td colspan=1 rowspan=1 > Stuff.co.nz t </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
What Norwegian patent proposals for submerged floating tunnel structures were proposed before 1950?
Answer:
In Norway, a first patent on Submerged floating tunnel structure was presented in 1923 by Trygve Olsen and a new request was done in 1947 by Erik Ødegård.