Dear Rabbi
Q, Can I buy a seadoo during three weeks, since it is available now at a discounted price and just give a deposit? I will not be having any intention to acquire the machine, until delivery after the 3 weeks, but still legally, it is mine. I this permitted? Can I take it for a test drive?

A. See question 100 in this forum where we mention that Igrois Moishe’s (O.C. 3, 80) opinion is that if the car is a pleasure vehicle, one should avoid acquiring it during the 3 weeks, as he has to pronounce the brocho of Sheheheyonu (or Hatov Vehameitiv), when taking possession. Horav Shlomo Miller’s opinion is that if one takes delivery of the vehicle after Tisha B’av it is permitted until the nine days begin, as no brocho will be recited yet.
See also similar question 596 on acquiring a new vehicle during this period: “However, during the Nine Days any purchase that provides enough joy to qualify as “Binyan Shel Simcho” should be avoided and no Hatov Vehameitiv should be recited. (Igrois Moishe ibid.). When this could not be achieved before the Nine Days, Horav Shlomo Miller’s Shlit”a opinion is that in case of need one may still sign a purchase contract. However, he should condition his signature on the contract and the deposit of monies, to only agreeing to purchase the car in the near future, not actually buying it and owing it now. Therefore until he takes possession of the automobile the ownership will remain in the hands of the vendor.”
In the case of a seadoo, that is primarily a recreation vehicle and also involves a degree of danger, Horav Shlomo Millers Shlita opinion is to preferably wait until after the three weeks. If that would imply a loss, it could be purchased before the nine days, following the above guidelines.
One is permitted to take the vessel for a test drive.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a