Originally Posted by Johnyo
My main concern is if the weather should get bad when traveling the Gulf between islands. I've watch several sailboats out in gale force winds and high seas and that spooks me a bit. But info about not being able to convert one is greatly appreciated. Thank You,
To push a 33' sailboat to 15kt or so would require 300hp or so assuming you could get it to plane.
Lets assume you can get to 20kt using 400 hp. At that speed you would be getting about 1/2 NM per gallon of fuel. If you are only using the high speed to get away from unexpected weather you are only going to be using it on longer legs of the trip. On shorter legs you would able to time your passages to coincide with weather windows. You will only be surprised on longer passages (lets say 400 nm or greater) when you will be several days out when the weather starts to deteriorate. The worst case is that you are halfway when you start to worry about the weather and want to outrun it. So you are 200nm from shelter and make 1/2 nm/gal so you need 400 gal of fuel for this sprint. At $3-$6/gal that's $1200-$2400. Also, at 6lb/gal, that fuel is about 2400lb. The added weight will slow you down so you won't even make the 20kt for the first 5-7hr. I used a Beneteau33 specs and the PsychoSnail boat speed calculator set for a planing hull. At best the B33 is a semiplaning hull but the calulator won't work to that high of a speed for that displacement and LWL. I assumed the all up weight would be 12,000 lb without fuel. BENETEAU 323 sailboat specifications and details on sailboatdata.com
The problem here is the B33 is designed to operate very well at displacement speeds and to resist the heeling of the sails
. Try to take it out of this speed and weight range and you pay a big penalty for it. Also working against you is that if you add the big motors at the back of the boat it will be really out of trim and sail poorly as well as motoring poorly.
The original post indicates boats down to 26' So let's look at the MacGregor
26 (MACGREGOR 26M sailboat specifications and details on sailboatdata.com
). This boat was designed to be motored at significant speed. In order to do this it has a lot more flotation aft, and uses water ballast which you can dump when you motor
fast or pull the boat out of the water. Together that means the boat doesn't sail very well except downwind. Upwind it doesn't have enough ballast except when it is light when the extra surface area of the fuller stern drags the speed down somewhat. As a boat to live on it's not bad, kinda small but with the powerboat hull roomy for its length. It was designed for a 50hp motor
. per this website (MacGregorSailors.com â€¢ View topic - 26X typical speeds under sail and motor
) you can motor at 10kt with ballast tanks
full and 14kt empty. At 14kt you can expect to use about 4.5gal/hr or about 3nm/gal. Using a trolling motor you should be able to get that up around 10nm/gal at 5kt. To get 200 nm range at WOT you will need about 60 gal of fuel ($180-$360) and that will weigh about 360 lb. As a boat to do the great loop it should be decent.
The down side of the MacGregor is that it is very lightly built in order to achieve the those speeds. That means that if you are caught out in heavy weather you are good and truly screwed, even if the boat doesn't roll over it is likely to sustain significant damage from pounding. I wouldn't take this boat into the Caribbean
The solution is to learn to deal with heavy weather rather than avoiding it. Like anything it takes practice.