Missing ballast?

[Daddyo]

Our new boat includes 1100 gallons of diesel tankage the Mr DeFever factored into the ballast. Problem is I won't be keeping that much fuel aboard so what do I do to replace the missing weight from the ballast equation?

 

[Marin]

A guess might be that deFever probably realized that the tanks on his boats were not going to be full all the time but would vary in weight with the fuel usage. So I'm guessing that it's not as critical as you might think. Our 36' boat holds 400 gallons of fuel. There is no discernible diffference in trim between having the full 400 gallons aboard as having only about 60 in the center day tank.

The 170 gallons of water in our lazarette tanks, however, do make a difference to the trim by a few inches between full and nearly empty.

 

[sunchaser]

Contact Mr DeFever direct in San Diego. I'd be interested in his answer. On my DF 48 it appears about 1/2 the main tank fuel *is above the water line. Why keep the fuel tanks low?

 

[Woodsong]

Daddyo,
clearly the answer is to keep extra whiskey aboard. either that or fill up those 1,100 gallon tanks now and not have to fill up again for 5 more years if just weekend cruising.

 

[markpierce]

Is it all in one tank?* I've got four and paid extra for a pump (and related system to filter fuel) to move fuel from one tank to another.* Here's part of it.

 

[Daddyo]

I think it's closer to 3/4 below the waterline. Fuels in 4 tanks. Contacting DeFever would make the most sense, I'll put in the call on Monday and post the results as it should pertain to most boats. The whiskey sounds like a good idea but after there's a nip in the air that Lagavulin or Doublewood Balvenie isn't going to last long!

 

[Larry M]

The design displacement for Hobo is 39,500 lbs (half load).**What exactly does half load mean?* 1/2 full of fuel and water?


-- Edited by Larry M on Saturday 13th of August 2011 05:47:42 AM

 

[Nomad Willy]

There is a fisherman here in Thorne Bay that obviously had that problem. The man that owns the boat now says the PO filled 2 of the 4 fuel tanks w sand.

Daddyo,**** Is the WL documented or marked on the hull? On my Willard there is a crease (like a caulked seam) running along about 2 to 3" above the WL as the boat sits in the water normally loaded. I try to keep my water tanks close to full in the laz to prevent having a light stern. A light stern (I think) will broach much more easily in a following sea. Can you see where the actual WL has been due to staining on the old anti-fouling paint? That may help. Have you contacted Arctic Traveler? You could duplicate his WL if he has had no handling problems as he's had lots of experience w his DeFever. Off the top of my head I'd say fill the aft tanks 1/2 to 2/3rds full of fuel and use the 2 fwd tanks until you get all the information you need. If the 4 tanks are amidships try running light and see how it goes. The boat may be on the heavy side and that would then be beneficial. One last thought .....Look at all 4 tanks and try to determine if they are all original equipment. If the 2 aft tanks are add ons it probably will be good to remove them. Whatever you do try hard to get all the standardized information you can and conform to that but consider that perhaps (unlikely though) that the stock Defever was light in the stern and many owners put in aft tanks to help trim the boat. In other words don't assume DeFever designed and built the boat so that it was perfect. But you may have an opportunity at this time to make make the boat more perfect. Once youv'e done your best on information seriously consider resale value and make your move.

 

[sunchaser]

On my 2003 DF 48 (made in Pocta) the two aft tanks hold 80 gallons each and the main tanks about 340 each. This is "live" meaning to the bottom of pick up tubes. The advertising brochure states about 15% more. The main tanks conform to the hull sides with the upper measuring 12g/" dropping to 8g/" on the lower sections.

I'd not advise any tanks be left empty. The downside is wet moldy fuel - a very corrosive mix. I've had*no problem running fuel that is two seasons old. By switching fuel around the age varies between 0 to 18 months.

Iron diesel tanks last a very long time if external and internal water are kept at bay.

 

[ausie bob]

the other thing to consider is all the extra weight we seem to be adding to our boats, like house batteries, inverter/chargers watermakers,bigger gensets, air conditioners ,more electrical gadgetsect, ect, many of these added after original launch. I have a 42 europa and a mate has the same boat and yet mine sits about 4 to 5 inches lower in the water.His is a minimal cruiser and mine has all the bells & whistles.

Bob & Cheryl
Grand Finale

 

[sunchaser]

On a hull speed trawler, the minimalist approach does not necessarily*equate to better mpg. On a planing vessel for sure with some overloaded to the point where they can no longer get on a plane.

Ballast in some cases is added by the MV builder to achieve desired stability, notably Krogen and Nordhavn and all sail boats. In my vessel I would not venture out in inclement weather without the 1100 lbs of batteries buried in the keel and at least 1/2 + water and fuel.