Wednesday, April 10, 2013

All sorts of hull shapes and sizes

We have certainly enjoyed our travels down the Costalegre with its beautiful beaches and cozy anchorages.  As we made our way from Manzanillo north to Bandaras Bay we discovered a leak in the boat that started out as a faint trickle and by the time we left Yelapa it was a full blown stream causing the bilge pump to cycle every couple of minutes.  At the marina in Puerto Vallarta we took a good look and found that the scupper drain that exited below the waterline had a crack in it that needed repair.  We tipped the boat over a foot or so by taking the jib halyard to the dock and cranking it over.  This raised the hole just above the water so I could temporarily patch it with some 3M Fast Cure 5200 Adhesive Sealant, doing a sloppy (but thorough) job of it while I floated on top of some fenders in the fetid waters of the marina.
Floating on Fenders while patching the hull

Great! The refrigerator is failing and we have a hole in the hull.  We better do some boat maintenance ASAP.  La Cruz was wonderful, for sure, and we enjoyed going out to hear Luna Rumba a few times but we hoisted the anchor, cleaned the barnacles off the flopper stoppers, and headed to Punta Mita for an early morning start up the coast.  We got a favorable weather window when the north winds calmed down for a while and then did the jump to Chacala. 

Ubiquitous hauling bike and Ez in front of a bed of Aloe Vera.


We anchored bow and stern there for the night and  continued north to Matanchen Bay where we met up with our friends on Luna Sea.  We spent a few days there and enjoyed seeing the town of San Blas and hanging out at the palapa bar on the beach with Hal and Nina but we needed to get north.  We had a hole in the hull for Dog's sake!

 While walking through San Blas we found Paul Hjelm's old van that Ocho Pies used to carry their equipment to gigs.  Connie was overwhelmed at the sight of the old beast!  She misses playing music with the band.  Now she gets her music fix by singing and playing the accordion or ukelele when she's not busy sailing the boat. 
Connie played in a band named Obrador.






It was good to have Ezrah along as a third crew member as we did the 36 hour non-stop to Mazatlan.  We took three hour shifts through the night.

I especially liked the midnight to three AM shift under a moonless sky with Pink Floyd in my ears.  We arrived in Mazatlan in the afternoon and surfed through the harbor entrance on the huge swell that had been closing the bar to traffic the day before.  Now we are at the Fonatur docks next to the work yard where we will haul out in two weeks to get the thru hulls fixed, the bottom painted, the hull sides painted, and various drive train items repaired.  We'll also drop in a new refrigeration unit and do some deferred maintenance here.

I love this marina because every day they are hauling out another sailboat into the yard. So I get to see all sorts of hull shapes and sizes.  And that is the belated topic of this blog.

Boat hull shape has trended in the past from deep and long to in the present as flat and long.  Long is good because your hull speed is determined by the length of the waterline as in this formula: 

Velocity of the hull = 1.34 times the square root of the length of the waterline.


At 34 feet 10 inches at the waterline, Traveler's hull speed is 7.91 knots. That's as fast as she can go.  Can her engine push her that fast?  Probably not. Can the sails? Oh yes.

Traveler has lots of hull under the water, which means lots of wetted surface and friction.  The keel, while not running the entire length of the boat, is a pretty good sized monster.  With this big keel, she likes to go in a straight line.  With her general hull shape she is pretty sea kindly, meaning that in a rough sea she is fairly stable.  In a rough sea she won't "seem" stable but believe me, she is more stable than many faster boats that have little fin keels and not much else below the waterline.

Note that she has a skeg-hung rudder. The skeg protects the rudder somewhat.  The keel extends about 8 feet fore and aft making her track well but not be very good at turning on a dime or backing up.  A little short keel part extends aft from the keel and houses the propeller shaft and helps protect the prop. The stern is rounded. Some call it a "canoe" stern.  It is thought that when a big breaking wave comes at you from the rear the rounded stern will rise through it easier than a big vertical flat stern.  The downsideis that we've lost some nice storage space in the rear and some flotation.  I'd say that the design of Travelers bottom is a nice compromise between the full keel behemoth found on old boats to the fin performance keel found on new, fast models.

So let's pull a few boats out of the water and have a look at their hulls.





This is the machine they use to pull the boats out of the water.














It reminds me of a machine found in a Doctor Seuss book, not this machine.  I could not find the one I was looking for which featured the grinch or somebody riding high on top of a strange contraption.




Once they get them out they balance them on the keel and add supports to keep it all upright.  Looks precarious doesn't it?
Harmony has a similar hull shape as Traveler. 

Here are a couple of Westsail 32's.  Note that the keel goes all the way from the front to the back. Some mean people call this the "WestSnail 32" but not me. I think they are beautiful. These small boats have traveled the world in safety.

And if you want to get totally historic, there is this little gem of a hull shape. 


On the other extreme, we have the fast boats.  Fin keel, spade rudder. Turns on a dime but might take a pounding in a big sea.



Would you name your boat this?  Other curious names we've see on boats are:
"Blow Me"
"Poopy Express"
"Master Baiter"
"My Assiss Dragon"
"Wet Dream"

And our final high speed craft picture is of Legacy a Saga 43, sailed by our friends Heather and Chris Stockard  
You can see on these performance boats that the bow is pretty vertical and the stern sticks out as far as possible.  This extends the water line so that the hull speed (as explained above) is very long in comparison to the overall length of the boat. Legacy's LWL(length of waterline) is 39 with a LOD (length on deck) of 43.  By comparison, Traveler's LWL is 34' 10" and her LOD is 41' 9". 

So as you see, there are many types of boat hulls out there, some short and deep, some long and thin, some with wide sterns some with rounded butts.  It is a trade off any way you go.  We think we've got a nice compromise, but still... it would be nice not to be passed by every time we have a boat come from behind us while we are in transit.  This is a common occurrence.  "Here she comes, there she is, there she goes."

We will be here in Mazatlan for about a month.  Feel free to come visit us and bring lots of money to pay our yard bills.  We hope to escape north to the Sea of Cortez when this work is done. 

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