Dirty bottom

Squirrel · 14 July 2005, 16:26

My RIB seems a lot slower this year than last year. It was out of the water over the winter but we did not redo the antifouling as it was fresh for last season and seemed fine. The hull is showing signs of going a bit green, but not exactly an aquatic hanging gardens.

Obviously I'm planning to give it a scrub next time I dry out somewhere, but could the light growth account for an 8kt reduction in top speed? I used to easily get up to around 48kts (GPS) last year, but now struggle to top 40-42.

I'm asking because I'm wondering if the engine might be a bit off tune too, but scrubbing the bottom is much cheaper! It was only serviced a couple of months ago.

Thanks

Dan

hannah · 14 July 2005, 16:31

i dont know if this will make any difference to the speed but try a hull cleaner , we bought some to clean off the dirty marks off of our rib , excelent job ! - but very strong .
atleast it will make the boat look clean

Stuart M · 14 July 2005, 22:10

What Hull cleaner did you buy? Was it just for dirty marks and did it work well?

Scotty · 14 July 2005, 22:28

My rib lives in the water for seven months of the year. It has to be cleaned every four weeks to get the slime off. Our top speed goes from 40 kts to 25 kts if we dont

Ask any sailor that races a yacht. We dont anti foul the boat as it takes one or two knots off top speed.

Squirrel · 15 July 2005, 08:33

Great thanks. I looked at it last night and its definitely getting worse quickly. Better get scrubbing!

pettal · 15 July 2005, 11:06

I don't know whether it's Guernsey in particular but when I cleaned mine the other week I noticed a large amount of jellyfish remains stuck to the hull!

This and the obvious algae bloom season might have a large impact on performance. For some reason in Guernsey the hulls seem to get a thin layer of algae slime that can cut the performance down dramatically.

Take it out of the water and spray with industrial bleach, leave in the sun for a few hours and then wipe over and it should all just fall off without too much effort.

Quite a few people over here tend to just find a deserted beach and beach it at low water and give it a quick spray with bleach. Not exactly environmentally friendly and I'm not suggesting that you should do the same.

However the harbour authorities use parazone when they clean the slipways, pontoons etc. So make your own choice on that one!

hannah · 16 July 2005, 16:58

Quote:

Originally Posted by Stuart M

What Hull cleaner did you buy? Was it just for dirty marks and did it work well?

it was called star bright hull cleaner , worked brilliantly our hull is nice , white and shiny !

wavelength · 16 July 2005, 19:12

The other option is that there is water under the deck. Mate of mine went thru all the hull cleaning etc only to find water was under the floor and in his case there was foam under there soaking it all up and making the outfit very heavy.

Squirrel · 17 July 2005, 21:31

Quote:

Originally Posted by wavelength

The other option is that there is water under the deck. Mate of mine went thru all the hull cleaning etc only to find water was under the floor and in his case there was foam under there soaking it all up and making the outfit very heavy.

Definitely not overweight and I've had a good look under the floor.

Petall, I've noticed a lot of blue jellies this year, must have splattered a few of them. I'm off to find a deserted beach....