Saturday, November 20, 2021

Mini Keels are not all the same!

There has been lots of debate about the choice of Mini-Keels or Daggerboards.  To boil it all down, Daggerboards allow you to point higher and can be raised to allow shallower draft.  On the negative side, the Daggerboard casings have to be cleaned and if you hit something, can hole your boat if they are broken.  Then there is the space taken up in the hulls for those casings.  Mini-Keels are simpler to use (there is nothing to do), simpler to clean (no casing), don't take up space in the hulls, and should allow you to beach your boat and have access to most of the hull for cleaning, etc.  They can also be sacrificial, so if you do hit something they just break away.

Generally, Daggerboards are associated with performance cats and Mini-Keels to comfort oriented production models.

However, this is not a discussion about the benefits of Daggerboards or Mini-Keels.  Let's assume you want a production catamaran (for whatever reason).  Therefore, it is extremely likely that you are going to have Mini-Keels.  The question is, are all Mini-Keels the same and the answer is, absolutely not.  You will notice that in the above list of features, I said, 'should allow you to beach' and 'can be sacrificial'.  That is because not all Mini-Keels feature these two advantages.

There are catamaran brands that make Mini-Keels part of the hull, like some Lagoons and others.  This means that they are not sacrificial.  If you hit something with your Mini-Keel on one of these boats and tear it off, that puts a hole in your boat and you will take on serious water!  (See Lagoon pic. right)

However, there are brands that make their keels sacrificial, like Leopard and Fontaine Pajot (as well as others).

In the case of current Leopard boats (see pic. left), they add stub keels, which project down from the hull a few inches.  Their Mini-Keels are hollowed at the top and the stub keel inserts into that Mini-Keel cavity.  They are glued in place with bolts put through the Mini-Keels and stub keels to hold them firmly in place.  This works well enough for the sacrificial element of these keels.  However, due to the hollow portion of the Mini-Keel design, there are thin walls on either side.  This means that the full weight of the boat cannot rest on these Mini-Keels, and Leopards manual states that the hulls must be supported at two bulkhead locations with some kind of jacks or other supports when one of their boats is out of the water for any reason.  What this means is that you cannot simply pull up to a shallow beach or boat ramp and let the tide go out so that you now rest on your Mini-Keels.  That is a real issue in some parts of the world.

For example, if you were to head up the Wadden Sea along the northern part of the Netherlands and

Germany, at each low tide the ocean retreats out past the Frisian Islands leaving you and your boat high and dry on the exposed bottom.  Each time that would happen, you would have to get out there before the water was completely gone and try to prop up your boat with some kind of supports.  As the sea begins to return a few hours later, you would again need to be in the water trying to remove those supports.  This would make the entire process nearly impossible and if you don't do it, or fail to get it right, you could seriously damage your hulls.

Fontaine Pajot makes their Mini-Keels a different way.  They have a socket in the hull that the solid Mini-Keel inserts into and this allows them to make the keels strong enough to support the weight of the boat.  Now, you can just let the tide go out and land on your keels.  If you are going to do this often, you might want to consider keel protectors (just to
avoid any small rock damage to the fiberglass).

Does this mean that Leopard or other brands that are not weight supporting are no good?  Of course, not.  However, it does limit you to certain choices and, sometimes, areas of sailing where this is not necessary.

For us, we have too many locations we are visiting where the tide changes are large and many of the ports we might stop in do not have enough depth, lock system or, other mechanism for keeping your boat afloat and we must land on our hulls.  Then there are places we plan to go, like the Wadden Sea, where we will land on the ocean bottom several times while crossing.  Finally, being a somewhat large catamaran, in parts of the world we are limited in where we can haul out.  If we can beach our boat we can do certain types of maintenance, like cleaning the bottom, etc. without the need of an expensive haul out which might not even be available.

So, in the end, we plan to find a boat that can be beached, if she has Mini-Keels, they must be both sacrificial and able to support the weight of our catamaran.

Addendum: We have settled on our catamaran and decided to go with a performance cat, with dagger boards and kick-up rudders.  The boat is the Solitaire 1490, extended to 50' 4".  She is designed to be beached from the get go, but we are adding some impact strength to the hull skin by changing from fiberglass to basalt fiber.  This will keep any small stones from 'denting' the surface skin while we are beached.  The kick-up rudders get them up and out of the way while beaching and we have shaft drive engines, so no sail drive poking down while we are on the hulls.  This will not be as convenient for cleaning the hulls while beached, but the boat will be 1 to 2 knots faster while sailing because of the dagger boards instead of mini-keels.  The boat also has a shallower draft of only 2' 2" with boards up, which is nice.