some examples:

http://www.maritimeadvocate.com/i23_usa.php

The subject is subjects

The phrase 'subject to' sounds innocent enough, but is one of the great divides between maritime law on either side of the Atlantic. Michael Marks Cohen of Nicolleti Hornig Campise Sweeney & Paige in New York explains

A COMMON practice in charter party negotiations is to fix on 'subjects.' In recent times, the most frequently discussed 'subject' has been the fixture based on a printed charter form 'subject details.' When one party walks away, the other party sometimes objects to the withdrawal as a breach of charter. Since the printed form often contains an arbitration clause, the issue is most frequently seen in the context of a suit to compel arbitration.

In London, a fixture 'subject details' is viewed as an agreement with open terms, which generally is not a contract at all. By contrast, in America, such a fixture will be regarded as binding, and arbitration often will be ordered in a 'subject details' case. It is one of the great schisms in the maritime laws applied on opposite sides of the Atlantic.

Other fixtures on 'subjects' likewise receive disparate treatment from English and American tribunals - for example, 'subject stem' i.e., cargo availability. In England, charterers who develop misgivings about whether a fixture 'subject stem' is advantageous can get out of it simply by failing to seek stem. By contrast, under American maritime law, charterers must exercise due diligence to obtain timely stem.
+++++++

http://www.iccbooksusa.com/index.cfm?fid=145

Fixture Recap:
A summary in short form, between brokers, of the terms of a charter party, which have been negotiated and agreed between their respective principals. The charter party is a formality and usually follows much later. Cargoes are often carried based upon the fixture recap.



--------------------------------------------------
Note added at 11 hrs (2006-03-04 07:05:19 GMT)
--------------------------------------------------

договор фрахтования переводится обычно как charter agreement , fixture - просто сделка.
trade fixture - торговая сделка

--------------------------------------------------
Note added at 11 hrs (2006-03-04 07:17:22 GMT)
--------------------------------------------------

I think that signed fixture is used here as a synonim for a signed charter party. It can be a fixture recap as well but for recap it is usually enough to confirm it by fax or telex. However signature on a printed copy of a fixture recap can be meant by the author of the text too.