Techniques for getting heavy twin keelers across the mud

[IJL]

That is why a fin keel is better , heeling reduces the draft

I think the abilty to sit in the cockpit with a mug of tea and pretend it was all deliberate is something of an advantage of a bilge keel boat. If you don't get the fin keeler of the mud you'll end up with your own thread on here with lots of keyboard warriors telling you what you should have done.

 

[dylanwinter]

It isn't a soft muddy bar anymore, it's hard sand. You won't plough through it and need to stick to the very narrow channel. I draw 1.5 metres and on neaps I can scrape in 4 hours before high tide. The channel runs from the mill rythe buoy to a point 10 metres south of the easterly cardinal then hang a left aiming for the first mooring buoy, bearing to starboard approx 150 yards b4 you reach it aiming between the starboard channel markers and the line of mooring buoys. Once past the first 3 or 4 buoys stick to the middle of the channel.

I did have a bit of a probe - and did not have the courage to step over the side for a walkabout

I can feel an exploration coming on

D

 

[VicS]

That is why a fin keel is better , heeling reduces the draft

The draft of a Centaur is 3' 0". The draft of a Pembroke, the fin keeled version, is 4' 3". To reduce the draft of a Pembroke to less than 3' would require it to heel more than 45° Not sure that this makes the fin keel that much better for creeping about in shallow water. Going to need a bit more than one overweight "hack" and a black dog on the side deck to tip it over that much for starters. Would not be able to use the engine at that angle either.

 

[Ammonite]

I did have a bit of a probe - and did not have the courage to step over the side for a walkabout

I can feel an exploration coming on

D

I'll lend you a spade if you like. 20ft trench, 3ft deep running all the way to buoy No.20 would be ideal

 

[Vara]

A set of tide tables and a watch is the simplest solution.

 

[BurnitBlue]

Same with a cruising catamaran. When it is stuck on the mud, it is stuck on the mud. Sliding across the mud with just enough water to float the boat would be very iffy. The propeller on my catamaran was so close to the surface that it was not effective.

Imagine sliding over mud in a bilge keeper when the keels straddle a rock or supermarket trolley and take out the prop.

 

[Greenheart]

Shifting a dead-weight is never easy. It hadn't occurred to me that it might be easier on dry land than in the water, though.

I bought one of those inflatable launching rollers, mainly for keeping the boat from smashing into the slipway while I run to the park for the trolley...amazing how singlehanders at my club come in and just wait holding the boat in waist-deep water, hoping someone on shore will bring their trolley down to them...it can be a long wait...

...I know boat-rollers are meant to be used in pairs for moving her over distance. Mine was rated at 400kg - I hope never to test that. The Chinese do it on a slightly bigger scale:

 

[Deleted member 36384]

You need a section of pipe that can reach the toe of your fin keels. The pipe should have about small holes, about 2 mm in diameter, 1 per 1" over 1' from the bottom. The pole should be sealed at the end where the holes are. The top section needs to have a fitting for taking compressed air (foot pump, dive bottle, small compressor). When one hits the mud, place the pole over the side and direct it towards the toe of the keel, switch the air on and then stick it into the mud and aureate the mud, repeat on the other keel, repeat as often as necessary.

This device lends itself easily for development where the ultimate solution is a keel shoe and toe device connected to an onboard compressor that allows one to ram the mud with aplomb, knowing that a few inches of mud will not perturb your departure. A word of warning though, excessive air below the boat could result in disastrous consequences for the freeboard.

 

[LadyInBed]

Might be worth shifting any moveable weight aft, to prevent the forward toes of the keels digging in ?

Isn't the nature of a sand bar that it rises from deeper water then falls again the other side?

Raising the forward edge of the keels just allows you to drive on harder!
I've run aground several times when arriving back late, trying to get back up the Wareham channel to my mooring. I've found that if I bottom and the boat stays in line, that indicates that I am still in the middle of the channel so I just try and power over the undulation.
If I bottom and the boat spins, then I've grounded on the channel bank, so it is then reverse power, often in blips, to reverse off and get back to middle channel.
If all fails, then it's engine off, kettle on and drop the anchor wi about a meter of slack chain so the boat just swings and not drift when the water comes back.

 

[Pitterpatter]

If all fails, then it's engine off, kettle on and drop the anchor wi about a meter of slack chain so the boat just swings and not drift when the water comes back.

Agreed. We have soft mud around our mooring. The drying depth changes by about 50cm depending on which way the chain is lying. I could of times I've been caught out. One time a full on charge at the sea bed got up to the mooring. Another time, after several attempts forward, back, forward, ... it was anchor out, quick beer, dinghy out, go home and come back in a few hours.

So, from experience, I think the best technique is to be patient and know when the seabed has won.

 

[prv]

One time a full on charge at the sea bed got up to the mooring. Another time, after several attempts forward, back, forward, ... it was anchor out, quick beer, dinghy out, go home and come back in a few hours.

So, from experience, I think the best technique is to be patient and know when the seabed has won.

I remember years ago visiting a pub with a pontoon outside, with not enough water to get alongside but a rising tide. Can't remember where.

The skipper knew from experience and the amount of pile visible that his boat would stop a certain distance out. So he aimed the bow at the pontoon and motored directly at it, at some considerable speed. We lurched to a stop with about a four-foot gap remaining.

Because of the height of the bow above the pontoon, we were able to make this leap with a standing jump, but there was no possibility of getting back. So we took a bow line with us, and simply tethered the boat like a horse to stop it drifting off completely.

We took a table by the window, and every time we saw the boat start to move at the end of its line, one of us would go down and pull it a bit closer. Eventually we got the bow close enough to clamber onto, and ran a stern line to the pontoon as well to start pulling round to lie alongside. We just about got moored up "properly" in time to pay for our lunch and leave again

Pete

 

[mtb]

D you could
use the engine to create a pool astern then if, you could move the boat towards the pool and keep making pools like that I recon you would get it moving
sand will move, I've done this a few times
mick

 

[LadyInBed]

D you could
use the engine to create a pool astern then if, you could move the boat towards the pool and keep making pools like that I recon you would get it moving
sand will move, I've done this a few times
mick

I hadn't thought of that one - reverse up to the sand bar and use the prop to scour a channel

 

[DRA]

We have, on occasions, managed to move a smaller bilge-keeler through the mud by rocking it from side to side - Grab the mast, lean out as far as you can to one side, then run to the other side of the mast and so the same. I don't rate your chances of this succeeding with a 26-footer but it might be worth a try. Usually we adopted the "make a cuppa and pretend it was all deliberate" ploy!

 

[sailorman]

We have, on occasions, managed to move a smaller bilge-keeler through the mud by rocking it from side to side - Grab the mast, lean out as far as you can to one side, then run to the other side of the mast and so the same. I don't rate your chances of this succeeding with a 26-footer but it might be worth a try. Usually we adopted the "make a cuppa and pretend it was all deliberate" ploy!

Thats were a fin keel come in handy, as i have already stated bilge keel are great, for standing yer boat, on a hard standing.

 

[kevburt]

In shallow water the prop sucks the boat down. If the bottom is too hard to push through you're better off motoring as slow as possible or, if possible get a long pole and push the boat along.

 

[CAPTAIN FANTASTIC]

To get a twin keeler unstuck, you need to move weight at the front, this makes the boat to tip forward, then put it in reverse and off you go; done it many times. However, to "walk" the twin keeler across the mad its a No No, can not be done; you may be able to dig a trench or to form a trench by reversing in and out and then trying to maintain the trench. Twin keelers are great boats, but require a bit of expertise to make them sail well. Also, it is easier to get off the mud if you reverse into it and then to get out put the engine into forward.

 

[Daydream believer]

Get someone in a MOBO to get in deeper water nearby & motor up & down to create a wash
A rib may do it
Then if you are only just stuck you may use max power & motor off on the wash


If the OB or inboard is not enough cut a hole in the cockpit & make a well. Then you can stick an extra outboard on for more power.
Really potty idea i know but might catch on

 

[paul-essex]

 

[oldbilbo]

.....I am after ideas for making progress across shallow water in both forwards and reverse. I am on a drying pontoon and the Rythe has a soft muddy bar that is good to pass at the earliest part of the flood

Most problems with boats have been encountered for centuries, and certainly the Dutch had this problem - getting laden vessels in/out of harbours/rivers with shallows at the entrance - in the days of working sail.

Brute force will just do damage. It seems clear that Archimedes' Principle needs to be employed to reduce the draught.

The Dutch used supplementary flotation lashed low alongside, called 'camels', with slings under the hull. These were sometimes assemblies of empty barrels, secured together into long rafts alongside. This reduced the draught effectively. You should be able to rig something similar, using e.g. a string of heavy-duty inflatable launching pillows secured under the turn of each bilge at low water.