New 45' - water ballast Y/N?


any problems with fouling inside a tank if saltwater use sometimes

or with alternate use of fresh/salt in a tank

btw I like the image of rolling cans of supply's
moving from side to side as needed
Check out the JP54. It has a rotating nav, kitchen, battery bank thingy in the salon to move the weight to windward.


definitely would add water ballast, make so much better to sail - discuss with your designer /structural people as they will need to allow for increased rig and structural loads, inc stablity and righting moment when it's all on the wrong side

will need to design in the plumbing, how to lift water into tank eg SoFo scoop or 'bilge' pump, dropping side to side (slide 'gate' valves remotely operated) 4inch dia pipe at least
we had 6inch (IMOCA size) on my Open 30 and dropped 300+ lites in less than 5 secs - a bit of overkill!
do you want to be able to pump from one tank to another?
able to pump water out -rather than 'dropped'
you will prob split to fore aft tanks so stop part filled tanks 'slopping water' about when part filled
so lots to think about on design side

for info
max lateral ballast allowed for racing is 10degees static heel, which is probably a sensible


I'm planning a new 45' performance cruiser, most of the time I'm sailing shorthanded or singlehanded. The boat is designed for that. Inspired by new First 44, we are now debating adding 300l of water ballast on each side. I don't race and usually stay longer on one tack ... good idea or bad idea? Space is not an issue, we are only planing 1 cabin aft.
My experience with water ballast is that it's racing only, cruisers can reef and if you want a faster boat then a bigger one is almost always a better option. Water ballast is however a relatively inexpensive and easy way to increase RM. If its a new build and the design is not constrained by rules and the budget allows then a canting keel offers a lot of performance advantages in exchange for more maintenance.

There isn't enough information in your post to really give a considered answer, how long is a long tack- 3 hours or 3 days? and what is performance cruising, you mention single handing which for most people is point and shoot yachting i.e where you can get to in a single day and find an anchorage. If you are talking about extended crossings then there are other factors which are more important such as storage, but I still really cant see the point of WB for cruising applications.

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Super Anarchist
43 south
I'm a water ballast fan. My late 90s 30'er carries 300 liters per side, and it really settles her down to ww, also an amazing feeling when sheets are eased and ballast dumped - she gets far more lively. I would however love to be able to control things from the cockpit - pump and valves are down near the engine, which necessitates someone going below prior to each tack (usually race 2h). Dumping from one side to the other, or just dumping, probably takes 30s-1m.


Super Anarchist
For water ballast plumbing, 3" or 4" for that size boat. Sliding gate valves can be opened with strings to the cockpit. Making the bends all nice and smooth curves in fiberglass instead of using plumbing 90 deg elbows will make transfer/dumps etc much faster.


As far as i'm aware only the IMOCA class is limited to 10deg static heel, and boy does it complicate the design choices. I will check my Class 40 this spring when we are back in the water and let ya know how far we tip at the dock !


Appreciate your comments on the WB - examining a retro fit for shorthanded Cookson 12 at around 350 - 400 kg WB. Target is long passage racing - RSHYR etc.

Our Hobart race simulation tells us that there are two primary modes that make up around two thirds 'on average':

1. Full heel upwind, cracked and JT angles - say 20 - 25 degrees heel.
2. Max heel under A3 or masthead sail - speed in double figures. This is around 15 degrees of heel at the limit of rudder adhesion in rough water.

The rough maths suggests that the inboard tank face should be at about 17 - 18 degrees to vertical.

We are paying close attention to the flotation, design displacement ~ 4,700 kg which with new carbon spars and some other work will be met.



Super Anarchist
One tank or two (per side)? If you do 2 tanks you can get the CG further outboard when winds are lighter and you only need to fill 1 tank. (You split the tank into an inboard and outboard tank)

And how is she downwind? Is everybody hanging on to the backstay and stern pulpit? In other words would it benefit from a stern tank as well in more downwind conditions?

Not knowing the boat very well (other than by reputation) I'd always optimize for condition 1 where stability is king.
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As far as i'm aware only the IMOCA class is limited to 10deg static heel, and boy does it complicate the design choices. I will check my Class 40 this spring when we are back in the water and let ya know how far we tip at the dock !
the most poplar is 10deg static which IIRC comes from the original rules by RWYC for the OSTAR
others use righting moments, measured, or 'knock down test' (pull over to 90degress)IMHO 10deg is a good starting point


Super Anarchist
Do loads really increase if you are replacing crew with water? Of course, one might be tempted to use the water when there is crew.