* Private equity firms and shipbuilders may bid - sources
* Maker of dredgers said to have 150 million euros EBITDA
* Rabobank unit backed earlier buyout six years ago
(Adds background on January interview, earlier buyout)
By Quentin Webb
LONDON, March 14 (Reuters) - Rabobank [RABN.UL] and Dutch billionaire Cees de Bruin are planning to sell a stake in IHC Merwede, the bespoke shipbuilder hoping to benefit from a boom in deep-sea mining, people familiar with the matter said. The part-sale of IHC, which designs, builds and equips vessels for land reclamation, oil drilling and deep-sea mining, could fetch hundreds of millions of euros and interest buyout firms and Asian and Middle Eastern shipbuilders, they said.
IHC and its owners -- Dutch lender Rabobank's private equity arm Rabo Capital, IHC employees, and a unit of de Bruin's Indofin -- hired JPMorgan and Rabobank's own investment bankers to help prepare a sale, the sources said on Monday.
Potential buyers were set to receive preliminary information ahead of a formal auction, one of the people said, adding that while a minority stake would initially be offered, bidders could ultimately be offered a controlling stake.
IHC has prospered building one-off ships for dredging companies such as Koninklijke Boskalis Westminster NV (BOSN.AS) but is now betting on a surge in underwater mining, buying a South African marine-diamond firm MMP last year, and agreeing a mining joint venture with DEME of Belgium last week.
IHC, which had earnings before interest, tax, depreciation and amortisation (EBITDA) of 102 million euros ($143 million) in 2009, is now generating about 150 million a year, one of the people familiar with the matter said.
Strategic bidders could include Singaporean group Keppel Corp (KPLM.SI), the world's largest oil-rig builder, and its domestic rival Sembcorp Marine Ltd (SCMN.SI); MISC Berhad (MISC.KL) of Malaysia; and Dubai World's [DBWLD.UL] Drydocks World unit, another person said.
Indofin investment director Maarten Douma confirmed the two banks had been hired but declined to comment further. A Rabobank official declined to comment. IHC Merwede, JPMorgan and Rabo Capital did not respond to requests for comment.
In January, IHC director Bram Roelse told De Tijd, a Belgian newspaper, it was seeking 300-600 million euros new capital to help fund foreign acquisitions. Roelse said IHC's revenues would grow from 1.1 billion euros to 1.5-2.0 billion in 3-5 years.
Rabobank, a co-operative that is the biggest Dutch savings bank, backed a 2005 management buyout of the firm from IHC Caland, now known as SBM Offshore NV (SBMO.AS). Rabo Capital took 49 percent, employees 33 percent, and Parkland, a unit of de Bruin's Indofin group, bought 18 percent.
De Bruin, whose investments span biotechnology, mining, and property, is worth about 1.1 billion euros, Dutch magazine Quote estimated last year.
The courting of overseas buyers suggests IHC's ownership was less controversial than six years ago. A Rabobank presentation about the earlier deal said the bank was "able to prevent three centuries of Dutch industrial heritage from falling into foreign hands". (Reporting by Quentin Webb; Editing by Steve Slater and Dan Lalor) ($1 = 0.7147 euro)