MARBLEHEAD – The seventh time may be the charm for the contractor who wants to rebuild and enlarge a seawall at 15 Spray Ave.A Conservation Commission hearing on the project began in March and has now gone through its sixth continuance without a decision.Groom Construction is in the process of renovating the home at 15 Spray Ave. The house is on the ocean, in a spot where powerful ocean waves strike the shore.Groom wants to make the seawall higher to protect the house, but neighbors on a nearby street fear that the new seawall will send those waves crashing onto their properties. They have hired attorney Carl King to represent them.King urged the commission not to take action until they had more information.Attorney Paul Lynch represents Groom.In July an obviously exasperated Walter Haug, the commission chairman, told project designer Peter Ogren he was ready to recommend denial, but he could not get a majority of the commissioners to follow his recommendation.The commission wants Ogren and the contractor to perform test borings under the present seawall to see if there is support for the new wall.Ogren told the commission Thursday that no test borings have been made because Groom is afraid they will undermine the present wall.Haug told Ogren he will not recommend any action until he receives the report from Childs and advised him to submit it before September.