Hull finish

   Hi all,

What's peoples opinion on underwater hull finishes...??? I know all the arguments for and against polishing, high grade wet & dry, laminar flow over the surface etc. But in practice what do you feel is the best finish on a few years old GRP hull.

Has anyone ever tried experimenting with some of the expensive automotive nano technology finishes to get an extremely smooth finish. I've seen the results of this type of finish and the water just beads and runs off very easily. 

Author	Message Share Topic Printable Version Delicious Digg Facebook Furl Google MySpace Newsvine reddit StumbleUpon Translate Twitter Windows Live Yahoo Bookmarks Topic Search Topic Options Post Reply Create New Topic
Splash II Send Private Message Find Member's Posts Newbie Joined: 22 Jul 15 Online Status: Offline Posts: 2	Post Options Post Reply Quote Splash II Report Post Quote Reply Topic: Hull finish Posted: 22 Jul 15 at 3:36pm
	Hi all, What's peoples opinion on underwater hull finishes...??? I know all the arguments for and against polishing, high grade wet & dry, laminar flow over the surface etc. But in practice what do you feel is the best finish on a few years old GRP hull. Has anyone ever tried experimenting with some of the expensive automotive nano technology finishes to get an extremely smooth finish. I've seen the results of this type of finish and the water just beads and runs off very easily.

JimC Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6661	Post Options Post Reply Quote JimC Report Post Quote Reply Posted: 22 Jul 15 at 3:52pm
	My feeling is that the behaviour of droplets of water on a dry hull is pretty much irrelevant. It is underwater and will be wetted. So just get it as smooth and fair as you can with the effort available. I suggest though you should be putting at least double the time into the foils as into the hull. This is especially true for pivoting board boats, where all too often that centreboard just stays in there accumulating gunge and gouges from one year to the next.

Presuming Ed Send Private Message Find Member's Posts Really should get out more Joined: 26 Feb 05 Location: United Kingdom Online Status: Offline Posts: 641	Post Options Post Reply Quote Presuming Ed Report Post Quote Reply Posted: 23 Jul 15 at 4:05pm
	Sanding chart on an old thread on SA here: http://forums.sailinganarchy.com/index.php?showtopic=84231#entry2068554

Rupert Send Private Message Find Member's Posts Really should get out more Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8956	Post Options Post Reply Quote Rupert Report Post Quote Reply Posted: 23 Jul 15 at 5:48pm
	I'm a fan of polish on a 1200 grit sanded hull. Mainly I like how easily it slides onto the trolley after sailing, and in my head it is fast, which is what matters.
	Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686

davidyacht Send Private Message Find Member's Posts Really should get out more Joined: 29 Mar 05 Online Status: Offline Posts: 1345	Post Options Post Reply Quote davidyacht Report Post Quote Reply Posted: 23 Jul 15 at 6:09pm
	Bit of a fan of a good soapy wash to get off the crud ... Then polish with Hullcote. Wet and dry finish on foils, something around 800 seems fine to me. IMO don't want them too polished as I think this encourages separation, besides which too shiny when you tip it in. As Jim said, time spent on leading edges and trailing edges of foils is well spent. Also transom edges and slot gaskets warrant a bit of care. Those who's formative reading was Elvstrom Speaks (should be on any bodies reading list) may remember Elvstrom talking about crud making a discernible difference to performance.
	Happily living in the past

JimC Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6661	Post Options Post Reply Quote JimC Report Post Quote Reply Posted: 23 Jul 15 at 7:29pm
	Rudders mirror finish if you can manage it. That would be good for centreboards too if you didn't have to stand on them to right the boat.