Check out Higher Hangers. They're great for our short closets. And I can measure the width of them to see if they'll fit into your 15" closet.
My wife hangs her dresses by folding up the middle and clipping them.
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Officially a SOB with a 2022 Jayco Precept 36C
Checkout my site for RVing tips, tricks, and info | Was a Fulltime Family for 5 years, now we're part-timing on long trips