Question on fuel bladders

[Bobmaddox]

Hello…. I want to add extra fuel/range to my CB29. The space where the table goes on the upper deck will hold a 100# bladder but what do you think about the impact on the boat’s stability will be by placing upwards of 700 pounds in that position ? The boat is already too sensitive to forward and aft weight so I don’t want to use the swim platform. Anyone have any other solutions to the need to carry extra fuel to achieve extra range question? Thanks!

 

[Maggie Anne]

HI Bob, I haven't heard of anyone adding fuel storage. You have got me curious though as to where you're heading with the extra range?

 

[Bobmaddox]

We’re are based in Puerto Escondido,, near Loreto BCS. There are no marinas or fuel services north of us, but lots of great cruising areas. Now, we have to get a fisherman to bring us diesel fuel if we wanted to make a longer trip.

 

[Chimo]

Doing as you suggest would make a significant change to the metacentric height. See https://maritimepage.com/what-is-the-metacentric-height-of-a-ship/ for background. The CB probably has a higher COG than the Sedan anyway but I don’t have the data. Bear in mind that your COG, and therefore your metacentric height and the righting arm will change depending on many other factors like tankage levels, passenger weight and where you store “stuff”. What you can be sure of is that you are certainly going to increase the tendency to roll.

 

[Bobmaddox]

Doing as you suggest would make a significant change to the metacentric height. See https://maritimepage.com/what-is-the-metacentric-height-of-a-ship/ for background. The CB probably has a higher COG than the Sedan anyway but I don’t have the data. Bear in mind that your COG, and therefore your metacentric height and the righting arm will change depending on many other factors like tankage levels, passenger weight and where you store “stuff”. What you can be sure of is that you are certainly going to increase the tendency to roll.

thanks for your thoughts..... my concern too! even though i can secure a bladder to the floor, the boat is so sensitive that rolling is an issue.

 

[Mihn]

Hello…. I want to add extra fuel/range to my CB29. The space where the table goes on the upper deck will hold a 100# bladder but what do you think about the impact on the boat’s stability will be by placing upwards of 700 pounds in that position ? The boat is already too sensitive to forward and aft weight so I don’t want to use the swim platform. Anyone have any other solutions to the need to carry extra fuel to achieve extra range question? Thanks!

 

[Mihn]

Put it in dinghy.

 

[TristenT]

I would avoid putting the weight up high. I some runs with extra fuel and the goal is to keep it as low as possible and move it to adjust any list and trim issues. We could run through to CG,GM,KG and GZ calculations but it’s really not going to provide that much usable information for the application. If you can add the bladder before deck as close to centerline and amidships as possible is best unless you want to counter any trim or list issues. If you are just running the bladder occasionally I would make a quick disconnect that runs to your fuel manifold pre racor filter. Have the full bladder on the aft deck. Run off the bladder first to empty it then fold it up and toss it in a hold for storage. My c28 has a space just aft of the engine that is where I am thinking of adding a bladder but I am not sure what you have for space.

 

[Eagle 2]

We've used Fuel Bladders before on deliveries to Cabo, PV, Loreto,ect from CA. As suggested, many times to even out the load, we would have two bladders, either fore and aft, or on each side of the boat if you have that kind of space. These were mostly bigger boats, that wanted to have the capacity to make Cabo from Ensenada, instead of stopping for fuel in Turtle, or San Carlos, which both can be questionable, and when they do have fuel, there are 15 sailboats ahead of you taking 30 gallons each that you have to wait for. 😎