There is little doubt that the 662 rowers from 43 nations will be itching to race and to show where they stand at the start of this all-important Olympic season.

Here are the crews to watch out for in the 14 Olympic class events. Included are the four Blue Riband events (men’s and women’s single scull and men’s and women’s eight). Racing gets under way in the Olympic events with heats on 4 May 2012.

Women’s Pair (W2-)
The highest ranking crew competing in this boat class in Belgrade is Great Britain’s Helen Glover and Heather Stanning. Glover and Stanning missed out on World Championship gold last year by less than a second. At the 2010 World Rowing Championships, the British duo also won silver. With a home OlympicGames in sight, they enter the 2012 season with high expectations for success. But the pair will havefresh, and perhaps unexpected, competition on their hands.
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Sitting in the bow of Romania’s number one crew is the formidable, and formerly retired, Georgeta Andrunache. Andrunache’s record is astounding. She won gold in the pair at the past three Olympic Games and also doubled up to medal in the women’s eight at the same time. Andrunache took a break from rowing after Beijing but at age 36 is now back in time for London with new partner and two-time Olympic medallist, Ioana Rotaru.

The United States pairing of Erin Cafaro and Eleanor Logan, both on World Rowing’s 2011 list of Top 10 female rowers will no doubt be a durable pairing. Both Cafaro and Logan are regulars in the USA’s repeatedly-winning women’s eight. Keep an eye out too for You Wu and Yulan Gao of China; silver medallists at the 2008 Olympic Games, they finished fourth at last year’s World Rowing Championships and will aim to peak in time for London.

Men’s Pair (M2-)
This field will bring surprises. None of last year’s medalling crews are racing in Belgrade; New Zealand and Italy are absent while Great Britain is presenting a new combination. But watch out for the very competent Greek crew of Nikolaos and Apostolos Gkountoulas. The Gkountoulas twins were fourth last year at the World Rowing Championships, but won world silver in 2010 and bronze in 2009.
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The Greek brothers will be facing a fired-up Germain Chardin and Dorian Mortelette of France. Chardin and Mortelette were part of the bronze medal four at the Beijing Olympic Games but have struggled to find success since. The French are aiming to qualify this boat for London and at Italy’s Memorial d’Aloja in early April they showed their form, having succeeded in winning against Italy’s 2011 world bronze medallists of Niccolo Mornati and Lorenzo Carboncini.

Serbia’s most successful rower Nikola Stojic will be racing in this boat class with partner Radoje Deric.

Women’s Double Sculls (W2x)
Coming out of winter training and British trials, Katherine Grainger and Anna Watkins remain unchallenged as the country’s top two scullers. They have also remained unbeaten on the international front since uniting in 2010. If past history is anything to go by Grainger and Watkins will make easy work of the double in Belgrade.
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But watch out for Germany. Top German single sculler Annekatrin Thiele is back in the double after a year out successfully racing the single. Thiele was part of the hair-splitting Olympic final in Beijing where she finished with silver by a fraction of a second behind New Zealand in the double. Now partnered with the very accomplished Britta Oppelt, this duo will be a boat to watch.

Keep an eye out too for regular 2009 World Champions and 2010 world bronze medallists Julia Michalska and Magdalena Fularczyk as well as the feisty Czech sisters Lenka and Jitka Antosova.

Men’s Double Sculls (M2x)
Racing at last year’s World Rowing Championships the German crew came second despite a last-minute change due to injury. The original crew of Stephan Krueger and Eric Knittel (2009 World Champions) are back together and will be the crew to beat in Belgrade. The Germans will be up against two very experienced crews. Slovenia’s Iztok Cop and Luka Spik are back together as they prepare for London and as Olympic Champions from Sydney 2000 and Olympic silver medallists from Athens 2004, this duo has a wealth of experience. Cop also has an Olympic bronze from the Barcelona Games in 1992 and London will be his sixth Olympic Games.

The French double of Cedric Berrest and Julien Bahain are also a handy combination. They rowed together in the men’s quadruple sculls in Beijing, picking up bronze, and their switch to the double in 2009 has led them regularly on to the medals podium.
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The big surprise, however, may come from Italy’s new combination of Alessio Sartori and Romano Battisti.When Sartori won his Olympic gold in the quad at the 2000 Sydney Olympic Games, Battisti had not yet started rowing. Now this pairing of experience and relative youth showed that they had great boat speed when they raced at the Memorial d’Aloja international regatta early April. But Italy is also boating two other crews in this event, one of which includes two-time Olympic medallist Simone Raineri and the other Olympic silver medallist Simone Venier. Italy is yet to qualify in this event for the London Olympic Games and they will be hoping one of these three crews will prove to be the magic combination. Be prepared to witness an Italian showdown in Belgrade.

Men’s Four (M4-)
Last year’s top two crews – Great Britain and Greece – will face off at Belgrade but with Great Britain
having adjusted their boat to include their top two sweep rowers, Andrew Triggs Hodge and Pete Reed. Hodge and Reed move from three years in the pair to join their country’s priority boat, the four. The new crew has been described by Hodge as ‘astonishingly fast’. Three of the British crew took gold in Beijing four years ago. Greece, with its unchanged line-up, will be the boat to test Great Britain.
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Germany and the Netherlands will also put up solid challenges. Both of these boats were in the final at last year’s World Rowing Championships and both have been tweaked to improve boat speed as they move towards London.

Lightweight Women’s Double Sculls (LW2x)
When Christina Giazitzidou and Alexandra Tsiavou of Greece crossed the finish line nearly four seconds ahead of the next boat it looked as if the Greek duo were in a class of their own. Tsiavou and Giazitzidou have taken World Championship status two out of the three times since joining together in 2009 and they have their sights firmly set on remaining at the top.
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To do this Tsiavou and Giazitzidou will need to hold off the new British combination of Sophie Hosking and Katherine Copeland. Hosking rowed to third at last year’s World Rowing Championships and she joins Katherine Copeland, world under-23 champion in the lightweight single, to form what British Rowing has selected as the fastest combination.

The Greeks will also need to be aware of Kristin Hedstrom and Julie Nichols of the United States. Hedstrom and Nichols come to Belgrade almost directly from winning US selection trials and their mission is to finish in the top four in Belgrade to secure their position on the US Olympic rowing team.

Lightweight Men’s Double Sculls (LM2x)
As reigning World and Olympic Champions, Zac Purchase and Mark Hunter of Great Britain may be feeling the pressure. But in Belgrade they may feel a little bit of breathing space as their closest rivals, New Zealand, will not be racing. Instead it will be up to Italy’s Lorenzo Bertini and Elia Luini to keep the British duo honest. Bertini and Luini raced at the Memorial d’Aloja in early April and finished a respectable fourth in the heavyweight double division which marked a good opening for their racing season.
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Likely to be entering into the medal mix is the Danish double of Mads Rasmussen and Rasmus Quist.
Rasmussen and Quist medalled at the Beijing Olympics but took a break from this event before reuniting last year to go after gold in London. The current World Best Time holders, Rasmussen and Quist, are likely to show improvements of training together when they race in Belgrade.

Keep an eye out too for China’s Chongkui Wu and Fangbing Zhang. Zhang was a finalist in this event last year and with new partner, Wu, there could be an element of surprise in their speed.

Lightweight Men’s Four (LM4-)
There has been no real dominating boat in the lightweight four over the last three years but there are some familiar countries that always make a good showing. Italy is one of these countries. The Italians have retained the same crew that finished second at last year’s World Rowing Championships and they will be up against 2011 third-placed crew in the world Great Britain as the top two favourite crews when they race in Belgrade.

The British boat has one change to last year’s bronze medal boat. Youthful Peter Chambers comes in and will join his brother Richard who has been in the four since 2007. Rob Williams and Chris Bartley make up the remaining two spots.
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It would be unwise to ever look past Denmark when it comes to the lightweight four. The Danes have won three out of the four Olympic Games that this boat class has been part of and rowing at all four of those Games in the lightweight four was Eskild Ebbesen. Ebbesen came out of retirement a year ago to go after Olympics number five. Last year the Danes finished fifth, but there is every indication they have the experience to step up into the top medals. Belgrade will reveal this potential.

Women’s Quadruple Sculls (W4x)
There seems to have been a reasonable amount of reshuffling by countries in their women’s quad. The 2011 gold medal German crew has brought in Carina Baer to replace Britta Oppelt who is now in the double. The silver medal USA boat is quite different in appearance, having only retained Stesha Carle from 2011. Both China and Ukraine, who were in the final last year, have made line-up changes with Ukraine keeping only Kateryna Tarasenko in the boat. China, meanwhile, has changed one crew member.
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This opens the event to potentially some unexpected results although Germany is still looking solid with their crew of Julia Richter, Tina Manker, Stephanie Schiller and Carina Baer. But watch out for Great Britain. They were bitterly disappointed to finish seventh in 2011 after being World Champions the previous year. The British have two new crew members including Victoria Thornley who has moved from the eight into stroking the quad.

Romania have added themselves to the mix with the goal of testing the waters for late Olympic qualification in mind. They have put together a boat that includes accomplished rower in the pair and in the eight, Nicoleta Albu.

Men’s Quadruple Sculls (M4x)
The line up in Belgrade is impressive. Reigning World Champions Australia may be absent but all other finalists from last year’s World Rowing Championships will be racing. Germany comes with the same crew that finished second at the worlds in 2011 and it is likely Karl Schulze, Philipp Wende, Lauritz Schoof and Tim Grohmann are the ones that will keep Croatia and Poland at bay.

Poland dominated this event for an astounding five seasons, from 2005 until 2009. But then Croatia shook up the Poles making 2010 Croatia’s year. The 2011 season was another story with both Germany and Australia stepping into the picture and Croatia finishing with bronze at the World Rowing Championships.
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Croatia and Poland have retained their same, very stable, crews with the aim of coming back into the gold medal spot. At last year’s World Rowing Championships Poland’s Adam Korol did not race due to injury and his return to the boat will surely be a boost. With Marcus Bateman and Matthew Wells of Great Britain moving from the double into the men’s quadruple sculls, it will be worth watching out for the renewed strength brought into this crew as well.

Women’s Eight (W8+)
Before the United States began their winning streak in 2006, Romania had enjoyed infinite success in the eight, taking gold at the 1996, 2000 and 2004 Olympic Games. Romania finished third at the Games in 2008 and they will desperately want to get back into the gold medal spot. Is this the reason Viorica Susanu has come out of retirement for 2012? The incredible Susanu has four Olympic gold medals, two in the eight and two in the pair. But, after Beijing, Susanu retired. She has reappeared in six seat of the Romanian eight and will no doubt give a huge boost to this crew that finished fourth last year.
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Romania have their work cut out for them as the British, who won world bronze in 2011, have just gone through a rigorous selection process to pick their eight which sees four new members. With this number of changes selectors must believe that this is the faster crew.

Keep an eye out too for the Netherlands. They have an uncanny habit of putting it all together when it really matters.

Men’s Single Sculls (M1x)
This event always attracts a large number of entries in Belgrade is no exception. But not only is the entry list large, it is also impressive in the calibre of the field. Leading the list is 2010 World Champion Ondrej Synek of the Czech Republic. Synek finished with world silver last year. In Belgrade, he will be up against his perennial rivals Olympic Champion, Olaf Tufte of Norway, Alan Campbell of Great Britain and Sweden’s Lassi Karonen.
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Karonen was fifth in 2011 and comes to Belgrade after a winter training season which has seen him hit personal bests on the indoor rowing machine. Tufte is the master of peaking just at the right time for the Olympics and Campbell continues to dominate the single amongst the British squad with his powerful sprinting abilities.

Added in the mix you will find the formidable Olympic finalist Tim Maeyens of Belgium and the lightweight World Champion Henrik Stephansen of Denmark. Maeyens and Stephansen are both aiming for Olympic qualification later in May and will be using Belgrade to fine-tune their racing prowess.

Women’s Single Sculls (W1x)
Racing at Belgrade is a chance to reveal how beneficial winter training has been. In the women’s single this will be apparent when World Champion Mirka Knapkova lines up against Sweden’s Frida Svensson and Xiuyun Zhang of China. All three of these single scullers are incredibly accomplished with years of international rowing experience behind them. Svensson was the World Champion in 2010 and Zhang won an Olympic medal back in 1996.
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Last year Zhang finished fourth and Svensson took fifth while Knapkova won gold by beating multiple World and Olympic Champion Ekaterina Karsten of Belarus, who will be absent in Belgrade.

The final is likely to be a race between these three scullers with Estonia’s Kaisa Pajusalu, Iva Obradovic of Serbia and Rachel Gamble-Flint of Great Britain hoping to show their boat speed ahead of their aim to qualify for London at the Final Olympic Qualification Regatta later in May.

Men’s Eight (M8+)
Will Belgrade be a shake-up for the dominating Germans? The first major race of the season is always
an opportunity for coaches to see how winter training went and for selectors to see if their choice of crew make-ups is making sense. For the men’s eight, three-time consecutive World Champions Germany will get to test themselves against 2011 silver medallists Great Britain.
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The Germans remain relatively stable with only one change from last year’s line-up – Filip Adamski moves into bow seat. The British have three changes in their boat with perhaps the most significant change being 20-year-old Constantine Louloudis. Louloudis comes into this very experienced eight directly from the under-23 level where he won the men’s pair. Even more remarkable is that Louloudis goes straight into stroke seat, sitting a couple of seats in front of 1992 Olympic Champion Greg Searle.

Hoping to push into the medals will be the Netherlands. The Dutch boat has made three changes from the one that finished sixth last year including 2008 Olympian Mitchel Steenman coming into stroke seat.

The 2012 Samsung World Rowing Cup I starts on Friday 4 May at 09.00 CET. Follow World Rowing's live coverage here, and watch out for all the latest news and race reports here. Also, keep up to date while on the go with World Rowing's mobile site, Facebook and Twitter. Send your comments and support for your favourite crews direct to the regatta's 'big screen' using the Twitter tag #wrcbelgrade.