* Buys 22 pct stake, has commitment to buy HAL's 32 pct
* Says deal would deliver strong increase in EBITDA
* Says may issue up to 10 percent new shares
* 17.20 euros/share offer represents a 61 pct premium
* Dockwise shares up 59 pct, Boskalis down 0.8 pct (Updates size of stake, share price)
By Gilbert Kreijger and Sara Webb
AMSTERDAM, Nov 26 Dutch group Boskalis , the world's biggest dredger, has offered 682 million euros ($884 million) for maritime transport group Dockwise to expand in oil and gas services.
Boskalis, which offered 17.20 euros per Dockwise share - a 61 percent premium - said on Monday HAL Investments, which owns about 30 percent of both companies, backed the deal and that Dockwise itself had expressed a "positive attitude".
Dockwise shares were up 59 percent to 16.91 euros by 1423 GMT after analysts said the offer price was fair and they expected the deal to go ahead without any counterbids emerging.
Boskalis later disclosed it had bought a stake of nearly 22 percent in Dockwise which together with HAL's 32 percent stake gives it majority control.
"This is almost a transaction between three parties: Boskalis and Dockwise but also HAL Investments as a controlling shareholder. HAL's support makes the deal very likely," KBC Securities analyst Wouter Vanderhaeghen said.
Boskalis said the deal would allow a more efficient use of vessels, equipment, and staff worldwide, and it saw scope for a broader use of Dockwise's vessels in dredging, offshore, and salvage projects.
"This step (Dockwise deal) fits in our growth strategy aimed at broadening our service offering for clients in the oil and gas sector," Boskalis chief executive Peter Berdowski said.
Dockwise, which transports oil and gas drilling platforms and other large objects via ships, said it was "well suited" to manage its operations on a standalone basis, and would seek clarification from Boskalis about the offer.
The deal would be earnings-per-share accretive and result in a strong increase in earnings before interest, tax, depreciation and amortisation (EBITDA), Boskalis said.
Kepler Capital analyst Andre Mulder estimated Dockwise would add 14 percent to Boskalis's 2013 sales and at least 30 percent to EBIT and EBITDA.
"This is a logical takeover," he said in a research note, given that Boskalis wanted to expand in the offshore sector and, to a certain extent, saw Dockwise as a competitor.
ING analyst Tijs Hollestelle concurred, saying Boskalis's strategy was "to become a prime contractor for the oil and gas industry, offering a wider total package of marine services to the customer. The equipment of Dockwise fits in perfectly here".
Boskalis, whose shares were down 0.84 percent to 30.86 euros, said its offer and the refinancing of existing debt would be funded from cash and new senior debt. As part of that, Boskalis expected to issue up to 10 percent of new equity.
Dockwise bought Norwegian rival Fairstar in July in a hostile takeover, and raised about 200 million euros in a rights issue to help fund the deal. ($1 = 0.7717 euro) (Editing by Dan Lalor)