larger transom valve on 96x

[grnwtrcruzn]

I've been thinking of adding a larger transom valve on my 96x . I've noticed a few have done it to their and was wondering if anyone had any words of wisdom/ caution before I break out the saw

[bartmac]

How large are you talking....ours on a 2000X is a little under 2" ID...but have noticed the time taken to empty the ballast....lots of other very impatient ramp users not realising that you can only really empty ballast on the incline of the ramp.Have recently bought a inflatable boat pump which incorporates a pressure limiting device.....so I was thinking of pressurising the ballast tank....very low to speed up the process

[grnwtrcruzn]

I was thinking of putting in a 3 inch. With the stock one I've motored for around ten minutes then pulled it at the ramp and still had a considerable amount of water in there. I usually do all my motoring/sailing with ballast full but would like the option on a nice day to drop the ballast and let the 90hp rip.

[Kittiwake]

I was thinking of putting in a 3 inch. With the stock one I've motored for around ten minutes then pulled it at the ramp and still had a considerable amount of water in there. .....

Before you do this I would consider an alternative explanation for your observation: that the stock valve is positioned in such a way (or the ballast tank is shaped in such a way) that complete drainage is simply not possible without tilting the bow up higher (ie. on the ramp). A trivial example would be 'that the lowest part of the transom valve opening is significantly above the bottom of the ballast tank'. I don't know whether boats built in different years can have slightly different positions of transom valve or designs of ballast tank. I first began to wonder about this possibility when I read a thread in which Doupirate described emptying his 26M ballast (his M is an earlier build than mine); but it is hard to be sure because we probably all have different sequences for opening the ballast valve on the retrieval ramp (and ramp steepness varies as does the steepness of the road home).
At present you are assuming that the ballast valve diameter is simply too small to permit adequately-rapid emptying under power.
Kittiwake

[Tomfoolery]

FWIW, I pull the drain valve and vent plug before I get to the trailer. By the time it's on the trailer and winched to the bow chock (still floating at the stern), most of the water is already out. I also pull the car ahead a little, go back and tighten the winch, rinse, repeat, and by then there just isn't much left in there. It seems to finish draining out in little time, but then, I've never actually timed it.

I would be curious to know how much water is left in the tank if you pull the valve with the trailer level, though. The ballast tank is at the center of the hull near the stern, but is split into two 'tanks' for most of the center of the boat, some distance above the lowest part of the hull bottom, returning to the center near the bow, so it would appear to not conform strictly to the lower belly shape of the hull. Just a mental exercise.

Look at the cross-sections top-left.

[DaveB]

I have a 1997 MacX with a 3 inch drain I think came with the boat. I empty the ballast at 7-8 knots in about 3 min. emptying it on the trailer at ramp takes 3-5 min.
You do have to take out the vent plug otherwise it will take much longer, it needs venting to flow fast.
Dave

I've been thinking of adding a larger transom valve on my 96x . I've noticed a few have done it to their and was wondering if anyone had any words of wisdom/ caution before I break out the saw

[grnwtrcruzn]

The vent plug on mine is pulled before emptying the ballast. Even on the trailer the water takes 20+minutes to drain (in excess of the amount of time it takes to lower the mask and unload the boat after a weekend out) and even then it still will leave a water trail on the way home if the valve is left open! I'll have to measure the valve size when I get home tonight to see the present size.

[HERNDON]

I have an early 96x and I open the vent and valve and slowly drive up the ramp and then park. I have never timed it
but I would guess 7 mins or so... I would shove a broom handle or PVC pipe through the valve opening to verify it
is clear.

Rob

[bartmac]

My earlier post didn't mention the fact that we only have a 15HP outboard and hence the only way to empty the ballast is on the ramp

[HERNDON]

and my earlier post failed to mention that for the last 10 years I have used a Tohatsu 8 Hp. on my 26x. I dont know if I had a
larger engine I would bother to empty the ballast prior to retrival. I usually sail within 1000' of dock drop the sails and then
aim for the dock.

[Catigale]

On the 2002 I drain while on the sloped part of the ramp, and it takes less than 5minutes. If there is a line at the ramp, I go up to the next in line and tell him/her I need 5 minutes to dump ballast. Never had a problem when they are informed, they often go arrange coolers in their boat or whatever.

[bartmac]

General ignorance of vessels using water ballast means comments like "gee you took on some water" a nearly 2" spout of water raises some eyebrows but when you inform other ramp users they generally realise the emptying process takes some minutes and that is just how long it takes.We tend to avoid busy ramp times and usually ramp conditions dictate medium to high tide to allow for floating our X back on the trailer and still have wheels on the ramp and not off the back of the ramp!!! Funny though the process of retrieving the X and the emptying seem to take an eternity....the old pot boiling thing....one thing to remember if you don't empty completely....the Mac bump won't work and excessive stress on the trailer weight wise makes for fun times figuring out how to get the last of the ballast out.......how much is left in there you wonder....only done it once and finding an incline suitable to purge the rest was interesting....all a learning process

[mastreb]

You can blow out the ballast using a 12v inflator connected to the ballast vent. Won't get the last little bit though.

[bartmac]

Yes the inflator idea will only work as long as the entire valve is covered by water....earlier suggestions were to only partially open to maintain the pressure on the water...haven't tried yet.The inflator I bought has a variable pressure switch and a 2 stage pump ie probably fan based and then a positive displacement pump.....PSI/Kpa rating of ballast tank?????low I imagine ,lots of surface area....was thinking .5 PSI same as some inflatable toy kayaks , certainly not 3 psi same as our inflatable tender....wouldn't want to crack anything