twin single keel

[Garth]

thanks for all your reply on my last quesion.
Becouse we are planing on coast hopping i was thinking of a twin keel as they can sit on the ground and don't need as deep water as the draft is shellower. With sailboat between 40 and 45 feet [at some stag around the globe i hope]. becouse new zealand has a good drop in the tide and can find your self setting high and dry. Is there any forseable problem with a twin keel cruising the globe not that ill be looking for any trubble

[Lendenbesten]

Garth,

We sail a twin keel cutter-sloop 50ft, 50k lbs. We just completed a 3 week visit to the rivers Stour, Orwell, Deben and Ore&Alden. Had a fine time drying out on twin keels and a rudder. Mind you you need a longer ladder to reach the ground than these boats with retractable boards, etc.

It's always good to look for sluices or little streams entering the river/lake/etc. Avoid those places cause there can be quite long "beddings" into the main stream of the river that will leave you with too much difference in height.

When you don't mind the larger wetted surface (which will leave you a little less speed) I think there are only advantages like less haul-out and no mechanical failures...

[Stephen Ditmore]

I think the research has shown that twin high aspect foils can be good, but twin low aspect foils suffer in windward performance compared to single keel boats. Instead, would you consider a single keel and twin strong rudders (on strong skegs or, if spade rudders are desired, with thrust bearings or stops at the tops of the rudder posts)?

[MikeJohns]

The twin rudders are good on a hard surface, but the small bearing area makes them prone to sinking into the ooze. Sheerlegs are a very good option too and work well (again on a hard surface).

I suggest you search for twin keels and have a read of what has gone before.

[westlawn5554X]

READ THIS: http://www.boatbuilding.com/article....gesoftwinkeels

[naval ark]

Originally Posted by Lendenbesten

We just completed a 3 week visit to the rivers Stour, Orwell, Deben and Ore&Alden.

My old stomping grounds, brings a smile to my face to know people still visit my 'home'...

Regarding your 25 ton cruising yacht - no, there aren't any drawbacks that you should concern yourself with. Yes, you will lose some performance compared to a yacht optimised for upwind sailing, but I don't think you have that boat to race around the cans. Downwind sailing might be more enjoyable compared to a single, deeper fin. More roll dampening, more directional stability, much less risk of digging the keel in and broaching (if you get up to those speeds ).

You just have to be careful not to dry out anywhere steeply shelving