Anti foul-speed?

P

penpal

Well-Known Member
Joined
18 Apr 2004
Messages
231
Location
Newbury, Berkshire
Visit site
I have a 32 foot semi, top speed 22, cruise at 18kn. Laterly i am only getting 12kn, although i had 16kn sog with the tide on sunday. I antifouled around June with Uni, one good coat as we changed the colour, did we use the wrong antifoul? Can this change the speed that much?
 
I wouldn't think that repainting your bottom with anti-fouling would cause a 6kn drop in speed.....UNLESS you used a completely different type that was incompatible with the previous paint. I would suggest before hauling out to put a diver in the water to see if you have fouled your prop(s), or if the paint is sloughing off or something else. If the different color paint was of the same brand...there should be no problem.
 
Slime could rob you of 6 knots. In June, the water was cold and there wasn't much growth, but there was a big spurt in July and August, so you may be surprised at how much fouling you have. There has also been a lot of barnacle growth this year, so although your hull may be fine, your sterngear could be an awful mess, and that will certainly rob you of 6 knots...
 
Yup, I concur with Wiggo. Barnacle growth on your props alone could easily lose you 6 kts and thats without considering fouling to the rest of the sterngear and the hull. Get your boat lifted and scrubbed and I'm sure your boat will be faster afterwards. If you find there's a lot of growth on the hull in only 3 months, then probably you would benefit from using a different antifoul, maybe an eroding type antifoul as your boat is not that fast
 
PhilipF said:
Interesting subject. Worth more information I suggest.
Click to expand...
International told me I could probably get away with Cruiser Uno and I do otherside of 40 knots- as long as I didnt spend all day at that speed.
As it happened I stuck with Trilux as it seems to work anyway.
I'd check the prop for barnacles..I m in the same marina as OP, and in the last weeks they.ve gone mad. I scrubbed them off, and it added a few knots back, but I d also just check the speed against the gps, as it seems to get a bit astray as the season goes on.
 
gjgm said:
International told me I could probably get away with Cruiser Uno and I do otherside of 40 knots- as long as I didnt spend all day at that speed.
As it happened I stuck with Trilux as it seems to work anyway.
I'd check the prop for barnacles..I m in the same marina as OP, and in the last weeks they.ve gone mad. I scrubbed them off, and it added a few knots back, but I d also just check the speed against the gps, as it seems to get a bit astray as the season goes on.
Click to expand...

That's really interesting....... Our boat does 34 knots but we spend most of the time cruising at 25 knots. We had always used interspeed, but in the interest of saving a few quid this year and with the mbm test results, we've changed to cruiser UNO. No doubt about it, the boats bum is much cleaner this year than the past couple!!
 
Penpal
My boat is a MF 925 single prop, 3 months ago used Blake Tiger Xtra anti foul and took a lot of effort in cleaning the prop and ruder,the results have been great. 18-22knts. Before 15knts max.
David
 
At the moment, we are languishing in port Dinorwick, a semi fresh water lock. Hope being the fresh water will clean M Farters bum. It has done before, so why not again.

Alternate being a £320 lift out and scrub for half an hour.

In the past MF has been taken down from 22 knots to 12 knots with weed and only in a few months. IT'S not as though she stands around alot.
 
You must log in or register to reply here.

Share this page

Top