Steel bilge keels sinking into soft mud

[jockster]

Hi, can someone out there advise me re: my colvic has steel bilge keels fitted and these do well on firm sand/mud and rocky bottoms but they sink into the mud where I am currently moored (fore and aft ground tackle). This did not occur instantly but after a few days after i brought her round. Locals say that this is due to the nature of the ground; the keels loosen up the mud and sink in eventually. Those yachts with thicker, more vertical fibreglass bilge keels remain upright. What can I do to improve the design of the keels to prevent my boat lying on her side? I did think of having the keels extended as they are about 6" shorter than the long keel, or perhaps some sort of round/flat plate on the bottoms to prevent sinking, although now I wonder if they might not remain more stuck when she lifts. Any advice would be appreciated.

 

[Bosun Higgs]

WE have lots of bilgies moored in a very similar situation. After settling down in slightly different spots over a month or so, they create a mud wallow for themselves and sit upright

 

[jockster]

Steel keels sinking into mud

Many thanks Bosun, It does seem to be taking a while.

 

[Caer Urfa]

[QUOTE Any advice would be appreciated.[/QUOTE]

Hi Jock
One of the best set of bilge keels I have seen fitted during my' Pre Buying Inspection' surveys on a Colvic Watson Motor Sailers as the new owner had similar problems.

You will see that everything has been 'Glassed in' and the new 1200mm long tubular bilge keels are 60mm dia Galvanised heavy wall tubing, all bolts 15mm dia Stainless steel.
Mike

 

[reeac]

sinking into soft mud.

Those tubular extensions to the keels look very good but they probably won't prevent sinking into soft mud which was the original question.

 

[LadyInBed]

Get her flying

You could weld 'Wings' onto the keels, though I have never seen a winged bilge keeler before!
You never know, you might just set a trend

 

[jockster]

Steel bilge keels sinking into mud

Many thanks to all who replied and especially for the pix. I guess it's a matter of sucking it and seeing what works.

 

[prv]

My boat has steel plate bilge fins either side of a long keel. The bottoms of the plates are turned outwards into little horizontal "toes" a couple of inches wide.

On my soft mud berth she dries upright, with the whole of the boat sinking into the mud.

Pete

 

[oldharry]

a common solution is to weld a steel plate to the bottom of the keel to form a foot. This stops that sinking feeling in all but the softest mud. The foot needs only to project 50cms or so each side.

Triple keel Trident 24s had them fitted as standard.

 

[jockster]

steel bilge keels sinking into mud

Thanks again to all respondents. I will probably go for the plate on base of keels. It struck me that the keels reach out at an angle from the hull and are also not on the same level as the long keel which means I may also have to extend the keels outward. Most bilge keelers in this area are original fitments and drop verticaly from the hull; they are also much thicker with a wider footprint.

 

[Scotty_Tradewind]

Bit of a bind to store but how about legs with large horizontal plates welded on the bottom?

Or perhaps you could have some form of floatation device fitted either side of your bilge keels....water wings style??? Post war my relatives used to turn the old long range fuel tanks from planes into canoes so an idea comes to mind..how about some skids off a small seaplane attached.

It will probably do the job to have horizontal plates fitted at the base of the existing bilge keels ... say 200mm wide and some 8mm thick.
Once they are in you will probably find she suddenly pops up as the incoming tide sees the buoyancy get the better of the fact they are stuck in some way... could be interesting
Those bars fitted in the photo look as is they are only good for sitting down on very firm ground and I bet they do the performance figures a lot of no good.

 

[Seajet]

For a start, how cruel to a boat to settle deliberately on 'rocky or sandy' bottoms ?!

The tubular jobs shown will not help do anything but create drag; the poster who mentioned boats in soft mud sorting out a 'wallow' for themselves is spot on - I've been playing around such moorings since 1974.

Better ( but more engineering, serious side loads involved ) to have deeper bilge keels, they won't prevent her heeling when aground much but would be an aid against leeway and stranding on hard surfaces.

I'd avoid wing style end plates, not much help but enormous loads; think how hard it is to lift one's welly boot out of soft mud !