Yes you do, unless you can ride along as crew with someone as l60f says. There are a number of good visa agencies in the UK that can tell you all you need to know. Try contacting these guyswho should be able to sort you out with a one or two entry visa pdq.
Visa and Transfer services for Russia, China and Ukraine : Travel Direct (UK) Ltd.
I have used them a lot in the past and they are very reliable but they are in Edinburgh. If you are really short of time and are based in the south, try
Star Visa Services Ltd - Russian Visas, Russian Consular Services & More