Investment Group Raises Bid for Shipper  NEW YORK (Reuters) - Buyout firm Fortress Investment Group  on Monday raised its offer for Stelmar Shipping Ltd. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=SJH.N target=/stocks/quickinfo/fullquote"&gt;SJH.N&lt;/A&gt; by  about 4 percent to \$703 million, but Stelmar's founder said he  still intends to vote against the deal.