Solent outdrive fouling

[TerryW2]

Can anyone help please?

I have a "fore and aft" mooring in Southampton Water. The outdrive weeds up in about a week. This completely ruins the performance. 20 knots turns into 10 at wide open throttle and fuel economy is unthinkably high. Planing is impossible.

If I could understand exactly how a little bit of weed can trash the performance so badly I might be able to work out a solution. Does anyone know in detail what the weed does to effect the performance e.g. increase drag? block water holes?

I have read the pros and cons of outdrive anti fouling which on balance seems to be of minor help and for a limited time.

Terry

 

[BrokerBen]

Weed disturbs the flow over the drives and props, causing everything to work less efficiently.

Shiny smooth bottomed boats are faster and more efficient.

If you can tilt your outdrives up, and perhaps hop into your dingy and give them a good scrub before you set off it will make a decent difference, expecially making sure the props are clear of worms and the likes.

Is the rest of your underwater area and planing surface clean and smooth? If not this will also make a difference.

I am sure you know your stuff, as a boat owner, but I would also recommend experimenting with the trim of the boat, might make a good difference to speed and handling.

Ben

 

[TerryW2]

Thanks for that Ben.

I think I am going to have to put my diving gear on and scrub. The hull was antifouled about 8 weeks ago and is still clean except a little scum mark at the waterline.

The trim tabs are as fouled as the outdrive. I have my doubts that they work properly when weed covered. Trouble is I can't do the speed to check them because the performance hit is so severe. I can hear the motor running ok.

In your opinion, does it sound right that a 5.0L 200HP powered 24 footer will be so "stuffed" by a just little greenery on the outdrive or do I have another issue that I haven't found yet?

If I couldn't see the anchor in its locker I'd imagine that I was dragging it along.

Terry

 

[Scubadoo]

You not the only one with this problem, I tend to clean off my duoprops every few months, mostly weed and a few barncles.

Your best bet is to Trilux antifoul for the outdrive which seems to be working well for me and also antifoul the trimtabs.

This year I am trying prop-shield which is a hard coating and seems to be working, I won't know for certain until lift out in March. But the weed has reduced.

 

[duncan]

simple answer is 'probably'

I use 4 coats of trilux on my drive every year and with a light scrubbing from time to time end up with a cleanish drive but little AF by the end of the season!

the real killer to performance are (1) little barnacles on the hull and (2) weed on the props causing huge inefficiency and break out at high revs.

 

[jonnybuoy]

I had my outdrive and trim tabs antifouled together with the hull earlier this year. But it only lasted 6 weeks or so, the stuff doesn't seem to work on metal. So every time I anchor up somewhere (or every couple of weeks) get down with a scrubbing brush. Can clean most of it off from the swim platform with the leg right up.