Advice needed: Keeping fin keel boat with sail drive on semitidal mud mooring?

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towermaid

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Please help. I'm looking for some practical advice on whether keeping a little old 27ft sailing boat with fin keel, skeg and saildrive on semi tidal mud mooring a daft idea...

In the interest of saving money I am considering moving out of a cosy but expensive Solent marina with all tide access to a semi tidal soft mud mooring in Portsmouth harbour.

I have rowed out to the potential site to get a closer look and sound out actual depths. At lw neaps the keel will sink into the mud but there will be just enough water to keep the saildrive clear. Since the mud is soft, i'm hoping the boat would just gently sink down and settle nicely at lw springs. The mooring itself is between piles.

My main worries are 1) stress/strain on the saildrive and engine mounts as boat settles into mud and 2) risk that mud blocks up the water inlet on the saildrive which in turns feeds the engine cooling.

Am I worrying over nothing? Should I give it a go or leave boat where it is? What experiencies good/bad do others have keeping similar boat in similar conditions?

p.s. draft of boat is approx 1.3m

Thanks, David.
 
As far as the Portsmouth mud is concerned, no problem. You'll gently sink in without noticing.
It's so soft that I'm surprised that the birds can walk on it!

Can't help with the saildrive, but I've seen plenty of outboard take it happily when they are left down at pontoons
 
There are lots of fin-keeled boats sunk into the mud at our yard. Certainly they don't fall over or anything like that. The mud is very corrosive where we are, though (metallic runoff from a scrapyard across the river) so we decided not to dunk our saildrive in it, and have wangled a deeper berth.

I doubt mud will block the inlet, as it will never get a chance to dry out hard. But I know some saildrive engines don't have inboard strainers - if you don't, I'd definitely advise adding one to catch any incoming debris.

Pete
 
I kept a catamaran with 2 Yanmar saildrives in a mud berth for 4 years without any problems. The sail drive legs and props were totally immersed in the mud at low tide. I found that closing the seacocks every time the boat would settle in the mud prevented it being forced into the cooling system. As the actual valve working components are a small way inside the seacock housing a small amount of water is trapped between the mud and valve workings as the craft settles down into it thus preventing any ingress of mud into the seacock. The incoming tide gently replaces the mud with water as the craft lifts off the mud. I did find that some years a few barnacles settling in the water intake slots in the bottom of the legs. These were easy to remove and not a problem as long as I antifouled the leg with Prop-O-Drev or a similar antifouling.

The same applies to any fitted seacock, heads etc. Although I no longer have a saildrive I do have a craft with a shaft drive which also is not a problem as long as seacocks are shut off when settling onto mud.
 
Hi, David.

If you're right about the saildrive leg staying above the mud, then I don't see any problem. The boat will dig its own hole and on most tides you'll be afloat in a muddy pool. In Southampton, the mud scours the antifouling off the keels and tends to form a thin, packed layer which can promote weed growth, etc. It is worthwhile with a half tide mooring to sort out where the scrubbing piles are, preferably with pressure washer, for a mid-season wash (& before the RTIR). I have known people with bilge keels which dunk the leg into the mud who added a new through hull to pick up water, with a standing pipe to allow it to be rodded through to clear mud plugs, barnacles and other detritus. That's probably more belt and braces than you'll need, though. I guess you'll just have to try it!

Rob (Mojo)

P.S. Not so much of the "little old" - she's a classic!
 
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David,

What you are proposing is exactly the same as I have. Deep fin Sadler 26 with saildrive on a 3/4 tide mooring in soft mud in Emsworth Harbour. If our experience is anything to go by she will be fine.

The best advice I can give you though is if at all possible when first putting her on the mooring each season, or if you've been away cruising for week or more, do it on a neap tide week rather than springs. That way she will slowly dig her 'hole' over a few tides as the range increases. If you chuck her on the mooring with a huge spring tide range, she will almost certainly fall to one side on the first tide and you'll end up with a big brown mark on the topsides and if you're unlucky seaweed on your shrouds and in the cockpit!!!
 
Thank you all for the advice. I need to get a bit more adventurous where I park the boat and trust that she'll be ok. Particularly like emsworthy's tip for putting her in on neap tide - genius. I would have make the rookie mistake of choosing springs!

p.s.
Hi Rob (Mojo) did you see lasts month's PBO? The Varne exterior photo was of Towermaid - It was taken a few years ago during a RTIR.
Total suprise to see this in print when I was flicking through the magazine at supermarket!
 
Yes, there was some forum discussion as to which Varne it was - I knew it was you as Towermaid always looks fresh and bright and those are your colours. Of course the crew somewhat gave it away...

Rob.

P.S. I kept Mojo on a half-tide swinging mooring for the first year. She dug a hole and at LAT there was a muddy pool around her and although the waterline was about a foot down she stayed upright, so the keel must have been impaled in the mud (like a mangrove). I moved her to a deep water mooring as, unusually, Mojo has an encapsulated lead keel and I didn't want her scouring through the gel coat leading to VERY expensive repairs.
 
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I really dislike the saltwater inlet valve on the saildrive leg. My sd20s have a gate valve with a narrow bore pipe. Gate valves have no business in any below water thruhull valve installation. Far better to install a seperate 3/4" thruhull and ball valve for the saltwater inlet - thus making it easier to shut off and also ensuring a decent water flow at higher revs (plus no worries about barnacles blocking it). If you use a strainer, then you need to shut the valve anyway before drying out otherwise you can get an airlock and burn out the salt water impellor. Make sure you make up a board to hang on the engine control to remind you to re-open the valve.
 
Talbot said:
I really dislike the saltwater inlet valve on the saildrive leg. My sd20s have a gate valve with a narrow bore pipe. Gate valves have no business in any below water thruhull valve installation.
Click to expand...

Agree about gate valves - but can you not change the valve on the leg? My Volvo one has what appears to be an ordinary ball valve, which I could unscrew and replace if so inclined.

(Actually I may well be so inclined, as it appears to be brass... :mad: )

Pete
 
prv said:
Agree about gate valves - but can you not change the valve on the leg? My Volvo one has what appears to be an ordinary ball valve, which I could unscrew and replace if so inclined......
Click to expand...

It is still a very small diameter (and probably brass!!)
 
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