Fin Keel Weakness

Fin keels compliment the sails of a sailboat remarkably. High aspect ratio keels, just like high aspect ratio sails, offer gains in performance while reducing the effects of unneeded drag and weight. While these underwater appendages work astoundingly well, they do have their limitations. If you are able to sail without conflicting with these weaknesses, a fin keel can serve your yacht very well. On the contrary, if you find that these weaknesses will interfere with your ideal method of cruising, a fin keel would not be your ideal setup.

Fin keels attach to the bottom of the hull via a small contact area. This small area has to withstand all the stress placed on it by the forces acting on the hull and the keel. When your yacht catches a puff of wind and heels over, the force on the sails heels your boat over while the force on the keel tries to right the yacht. The junction of the keel and hull is under extreme stress as the hull is trying to pull up while the keel is trying to pull down. If you combine these stresses with heavy pounding seas, the loads experienced by this small area will climb exponentially. With time and stress, fatigue will set in and stress crack will begin to form around junction of the keel and hull. 

Another problem with fin keels is they are not very well protected from impact. They are, by design, a very long lever arm. If you were to strike an underwater object, be it a sunken log or the sea bed, this force is going to be multiplied and then transmitted to the rest of the yacht via a very small area. This small area will be subjected to extreme loads and can form cracks.  

In the Chesapeake Bay, most creeks are around 4.5 to 5 feet deep. Sailboats with shallow enough drafts will attempt to enter these waters, typically running aground at some point during their life. When a grounding occurs, the forces excerpted on the keel are enough to create these characteristic cracks in the front of the keel near the hull.  

These cracks are just the visible damage that occurs to the yacht, but the forces run much deeper and so do the damages. The bolts that attach the keel to the hull are located in the bottom of the bilge and are often bathed in bilge water for the life of the yacht, causing corrosion to wreck havoc on the bolts. The combination of these bolts rusting away and the forces from an impact can cause the keel to actually fall off! If the keel falls off, you now have two very major problems.  

First, the keel is gone and the keel bolt holes (which are rather large) are open and flowing a lot of water into the hull. If these holes are not plugged quickly, your yacht could sink from the in flowing water! 

Second, the keel is gone! You no longer have any ballast or righting moment to counter the sails. If a puff of wind heels you over, you will capsize! Worst of all, if you do capsize, you will not right yourself because the ballast is gone. Losing your keel is not just terrible, it is horrible! 

If you decide on a yacht with a fin keel, don't try exploring shallow waters. If you run aground, damage will occur to your underwater appendages and the repairs can be quite costly. Think of a fin keel yacht as a deep water dream machine! It will glide through the waves with ease and efficiency, but it is a fragile dream machine. If you hit it too hard, it will break along with your dreams. 

Fin Keels

Fin keels are the epitome of performance! They project out of the hull as a high aspect ratio appendage with a long leading edge to generate as much lift as possible with as little drag as possible. The narrow fin slices through the water with ease and its airfoil shape adds to its efficiency.  

The long fin keel locates the mass of the ballast far from the hull, providing a long lever arm to aid in righting moment. This added leverage uses the ballast more efficiently which means that less ballast is needed. Less ballast also means less weight which directly relates to the yacht having a lighter displacement. Lighter displacement gives the sailboat greater speeds in light airs, and much greater speeds overall. Fin keels truly are the ideal underwater appendage from a performance standpoint! 

If your dream yacht is a high performance machine that will zip through the water toward your destination, be sure that you size your keel accordingly to the waters you intend to navigate. The longer the keel, the better the yachts ability to point, but the yacht will also have a deeper draft. 

If you plan to cruise in waters that average around 6 feet deep, then a 10 foot keel may be problematic. Your cruising grounds will be severely restricted and limited to only the deeper areas. If you went with a shorter fin keel, you will still have the performance benefits of a fin keel with the increased cruising realm of shallower waters. 

It would behave you to look over the charts of your intended navigable waters and examine the charted depths. Identify the creeks and rivers you wish to sail into and record their water depths. By compiling the data by depth, you can see how different drafts will remove potential cruising waters.  

For example:

Creek A, Creek B, and Creek C have depths of 4 feet;
Creek D, River E, and Bay F have depths 5 feet;
River G, Bay H, and Creek I have depths of 6 feet.  

If you choose a boat with a draft less than 4 feet, you could cruise all the bodies of water that you have identified.
If you choose a boat with a draft less than 5 feet, you can no longer enter Creek A, B, or C. 
If you choose a boat with a draft less than 6 feel, you can only cruise in River G, Bay H, and Creek I.

If you did not look at your local charts before you purchased your yacht with a 10 foot draft, you would be disappointed when you can not enter any of the cruising waters you wanted to explore! 

While fin keels are excellent performers, be sure to size your keel accordingly to the waters you wish to cruise instead of solely focusing on the performance aspects of the keel length. 

Wedding Registries for Liveaboards

Registries are magical accounts where you can choose mountains of gifts that you wish to receive for your wedding.  Normal registry items consist of fancy dining ware, crystal, wine glasses, vacuums, and endless amounts of household appliances.  This is all well and good…if you live in a house.  The registry of a live-aboard is a tricky thing to create.  I had to completely alter my thought process to include plastic instead of glass and anything that happens to come with a compactable capacity.  I managed to do a pretty fine job of it in the end, and we ended up with a wide variety of handy boat-friendly options.  I’m going to list some of the things we are most happy with. 

1.       The Fruit Hammock

a.       This is a FANTASTIC way to store fruit and vegitables that don’t need refrigeration such as apples, bananas, oranges, avocados, and onions.  This item is inexpensive, so it was a perfect gift option for my college friends who are still trying to begin their careers.  The hammock hangs completely out of the way on the nobs that open our porthole where it is accessible from the galley.  It expands to fit tons of food that simply swings back and forth during wakes and storms instead of rolling all over the counter.    

2.       Solar powered Inflatable floating lanterns

a.       These are a beautiful invention.  They store easily and when we are underway we simply flip them over so that the little solar panel on the bottom faces the sun.  When night falls and we wish to read or dine outside, we blow them up and place or hang them around the boat.  If they fall overboard they are easily recovered since they float and they come with three light settings including a flashing red SOS.  Herby takes one with him on the dingy when he rows Morty ashore so that I and other boats can see him.  We registered for and received 8 of them!

3.       Two-Person Hammock

a.       If you don’t already have a hammock on your boat, you’re doing it wrong.  There is nothing more peaceful than being in a hammock as it gently swings you with each subtle movement of the boat.  Herby and I like to relax in our double hammock while I read to him in the evenings.  It even closes up above us to keep out the bugs, and when it gets dark, I use a solar lantern to see!

4.       Flexible Wine Glasses

a.       We have broken all but two of the original glasses Herby had on the boat when I moved in.  They fall in the sink during wakes, they clink together in storage, and they slide off the table when bumped, which happens a lot since there isn’t a lot of space to move around the salon table.  I registered for two types of wine glasses, therefore, that give off a classy appearance while remaining nearly indestructible.  Govino is a company that makes adorable Plexiglas wine glasses that flex in your hand and include a handy dimple for your thumb.  We have received tons of compliments on them while entertaining.  They are super light and make absolutely no sound when they bump together on the shelf.  I also registered for high quality plastic stacking wine glasses because they stacked so beautifully I couldn’t resist. 

5.       Britta Filter

a.       The Britta filter has become our best friend.  The water that stores in our tanks comes out of the faucets tasting terrible.  We previously fought this issue with tons of water bottles which was incredibly wasteful and costly.  Once our tank water flows through the Britta, it tastes completely normal!  We simply keep the filter in one half of our divided sink so that it doesn’t knock over.  We drink so much water there is no need for refrigeration.  We simply fill it with as much as we plan to drink at that time.     

6.        Stand-up Paddle Board

a.       Stand-up paddle boarding is both super fun and quite useful.  If you are cruising or living aboard, I highly recommend getting an inflatable paddle board.  It stores very easily and does not take much effort to inflate.  It’s a fun way of exploring new areas if you are anchored in a protected creek and it serves as a quick and easy way to get your dog to shore if he is small and has a low center of gravity like Morty! 

So there you have it: six awesome and smart registry items for live-aboards.  We are so very happy with our decisions!!  

Keel Designs

When searching for your dream liveaboard sailboat, the variety of keels may raise some questions as to which one is the best?

The truth is, they are all good and bad at the same time. You have to find one that fits your needs and demands, and has drawbacks that you are willing to accept or don't bother you.

In general, keels are either fin or full. Within these two broad categories are a multitude of variations, but in general, they fall into these two camps.

Fin keels are characterized by their long, high aspect ratio projections from the bottom of the hull. They provide greater performance and less drag, but they are not as strong as a full keel. The hulls have a shallower bilge which results in less wetted surface area, all leading to greater performance.

Full keels are characterized by their low aspect ratio projections, running the length of the hull. They provide less performance, more drag, and add lots of weight to the yacht. This may sound like a horrible keel choice, but it does have two strong characteristics. It is strong and it creates a nice slick to windward when hove to.

Full keels offer a greater area of attachment to the hull and spread the forces from the keel over more of the hull. This very strong attachment to the hull resists breaking under normal and extraordinary conditions. 

Normal loads on the hull-keel joint are experienced when the yacht heels over and the keel acts as a lever arm with the ballast at the end. This load is torquing on the hull, trying to turn the hull back to a vertical orientation. A full keel will spread this force out over a greater area and lead to less stress cracking in the hull at this junction.

Extraordinary loads occur when a yacht is grounded. When the keel smashes into the seabed, all that force is transmitted to the hull via the hull-keel junction. Spreading this massive force over a larger surface area decreases the pressure at this junction and reduces the risk of damaging the yachts hull. This means that a full keel boat will survive coming in contact with the bottom with less risk of damage or holing. 

A full keel provides more drag through the water when hove to and sliding sideways. This added drag will lead to a slower rate of drift and provide a very disturbed slick to windward which will calm the approaching seas from breaking waves into rolling waves. 

The negative attributes of a full keel is the increase in wetted surface area adds lots of resistance which leads to slower sailing speeds. A low aspect ratio of the keel is simply less effective at producing lift when compared to a keel of the same surface area that is high aspect ratio. This is why racing yachts all have very deep fin keels.

If performance is your top priority, a fin keel will be your desired keel platform. If you want a bit more forgiveness with exploring new waters and will be satisfied with a slower boat, a full keel will be a great platform to look into.

Water Tank Plumbing

Where the tank connects to your plumbing is a topic for discussion as the two choices have alternate attributes. The plumbing can either connect at the top of the tank or at the bottom of the tank. 

If the plumbing connects at the top of the tank, a hose or pipe will need to be led down to the bottom of the tank and the tanks will drain via siphon. Water being drawn from the tank will flow up the hose and into the boats plumbing. When multiple tanks are connected to the plumbing in a system, they all depend on having a siphon to drain them properly. If an air lock forms in any of the tanks feed tube, that tanks water line will need to be primed to allow it to feed properly. 

This may seem rather inconvenient, but there is a reason to connect the plumbing at the top of the tank. If the plumbing were to slip off of the tanks boss, the water in the tank will not drain out. Instead, nothing will happen and your fresh water will remain inside your tank awaiting your use. You can either reconnect the plumbing to the tank or remove water through the tanks top access. Either way, your water will remain safe and stored until you are ready to get the water out.

The alternate option is to connect the plumbing to the bottom of the tank. This may seem the most logical as water will drain out of the boss and into the plumbing, never suffering form air locks or other related issues. If your pump stops working, water can still be removed by opening a drain lower than the tank and letting gravity do the rest! 

While this may seem the most logical, it is also plagued by a serious problem. Should the plumbing slip off the boss, the tank will empty its contents and the fresh water will become lost to the bilge. If you loose all your water while out at sea and have no method to replenish your stores once repairs are completed, you will be in serious trouble!

While it may seem trivial, the security of your water is worth the headache of dealing with air locks and the need to prime water lines associated with a top connecting tank. Be sure that the tank has a large viewing port on the top that will allow you to fit a pump or hose into the top to withdraw its contents should your plumbing system fail.