I've used Hillman strap toggles on my 23.5 Hunter to add Stern rail stanschion fitting to deck [no access].also jib track to cabin roof.Worked great.Home Depot,Lowes have them 3/16to 1/4 in.Anything bigger try Fastenal.com.Easy to use,Drill 1/2 hole ,insert metal end. push plastic cap flush ,snap off two plastic peices.done bolt whatever .Bolt can be removed and reinserted.Same as WM,half the price!!!