Ballast Vent location

[Memmer99]

I just installed a fully integrated ballast system on my 89 Sunsport. I put a 650lb in the rear ski locker (with some modifications,) 1000lb triangle sac under the front playpen (I'm sure it only fills to maybe 500lb max.) Both sacs are run on a reversable Johnson ballast pump just like the one from wakemakers connected to a 1" through hull.

My question is where should I put the through hull for the vent lines? I've heard that vent position is crucial for everything to work properly. Anyone know if there is a rule of thumb for this? I was thinking of drilling the front vent right behind the speaker location which is no more than a foot above the sac. The rear vent should not be an issue because there is space to basically put it anywhere.

I promise to get some pics up for you guys but it's raining here in California so the boat is under a tarp at the moment. It looks like we may be rained out for Memorial weekend too, Which REALLY SUCKS!!! :(

[Fman]

I just installed a fully integrated ballast system on my 89 Sunsport. I put a 650lb in the rear ski locker (with some modifications,) 1000lb triangle sac under the front playpen (I'm sure it only fills to maybe 500lb max.) Both sacs are run on a reversable Johnson ballast pump just like the one from wakemakers connected to a 1" through hull.

My question is where should I put the through hull for the vent lines? I've heard that vent position is crucial for everything to work properly. Anyone know if there is a rule of thumb for this? I was thinking of drilling the front vent right behind the speaker location which is no more than a foot above the sac. The rear vent should not be an issue because there is space to basically put it anywhere.

I promise to get some pics up for you guys but it's raining here in California so the boat is under a tarp at the moment. It looks like we may be rained out for Memorial weekend too, Which REALLY SUCKS!!! :(

This might be a better solution or something for you to consider:

Use a one way check valve and "T" it into your drain line right before the thru hull exit, you wont need to add an extra thru hole and it will act as an additional overflow valve when the bag is full. You can pick up the check valves from wakemakers.com

[docdrs]

With the reversible pumps the the bag is filled and drained thru the same line.
A vent/overfill line is needed to allow this. The only thing to keep in mind is to have your rear vent lines as high as possible and ideal would be on the opposite side of the boat as when you fill , if the top of the sac is above the vent line the bag will self drain. this occurs when surfing due to the leaning of the boat and the bag being higher. It happens to me with my 1100 lb bag on my 21v.......i need to fix it .....i guess i could just get more hose and reroute my lines to opposite sides.....thanks i just solved my prob :)

[saltare inverts]

How long does it take to fill with that pump?

[ScottnAz]

I'm not so sure vent location is crucial, other than the fact it needs to be higher than the bag, as Doc pointed out. As far as length of run, my center sac vent line runs a good 15' before it exits the boat.

[Fman]

Woops, I did not see it was on a Johnson impeller pump. This changes everything, sorry bout that.

[87SunSportMikeyD]

Hey Memmer - Nice freaking work man!! Lets get some pics of that ASAP!! :) Wish I could get that big sac in the rear.

Vent/overflow placement is CRITICAL! The reason this step is SO important in OLDER boats is that our compartments do not fit our sacs correctly. If you have a compartment where your sacs are able to fill to capacity (and then some) without touching any walls, then you have no worries. The sacs are very strong and can overfill about 10-15% without worry of popping. Capacity is greater than stated on the sac. The pressure will force water up to a foot high through your vent line and out the boat.

However especially with Simer/Johnson/Jabesco reversable pumps (more power), the risk to damaging your fiberglass is great. Overexpading the sacs can EASILY break wood or split fiberglass. You need to align your vents to allow the sacs to fill witout damage the boat, but also let you fill the sacs as completly as possible. If the vents are too LOW, ie half-way up the sac, then the sac will never get more than half way full.

The only way I know to really get it perfect is to mock it up when you are floating around. Hook up the vent line and one way swing check valve and then fill the sac. Keep a bucket handy for the overflow. Once the sac gets full, raise/lower the height of the line until the sac fills to your needs.

Best of luck and document for us! :)

[87SunSportMikeyD]

Memmer I had two threads from you on this topic so I merged them to this thread. :) FYI

[Memmer99]

Thanks for all your input! It sounds like the front vent will not be the issue like I originally thought. I think I'm going to give it another test like Mikey suggested. I'll attach the vent to the sac and fill it in posistion (on the opposite side that I surf) until it's is full. I'm thinking a good spot will be up high on the port side next to the rear seat cup holder. This way the vent will be higher than the bag when it's full and in front of the bag so it will not drain when under power.


SALTARE INVERTS, The pump is rated at 12 Gallons per minute and I ran all 1" flexable PVC for my fill/drain lines. I did a test last weekend and it filled the 650 and an old 350 I had in my bow in about 7 minutes. I went with the Johnson because the Jabsco is only 8 GPM plus it cost about $100 bucks more. I got a great deal on the Johnson for only $158 here. http://www.marineandrvpartssupply.com/johnsonPump_parts_List.html
It is a little loud but hey that just less of a chance of me running it dry if I can hear it.

[87SunSportMikeyD]

I have ran mine dry for several minutes with no ill-affects. Pretty sure it's gotta REALLY run dry to hurt it. My Simer also came with an extra impellor.

I have not really been able to decide exactly where it should go for the front sacs... Please let me know if you experiment with the front ones.

[ScottnAz]

If the vent line is the same size/capacity as the fill line, I don't see why placement would be so critical.
I understand a bag filling past capacity or locker restrictions and therefore doing damage to the boat, but also know water will take the path of least resistance, and the large bag will conform to an otherwise smaller storage area and then spit out the overflow/vent line and out the side of the boat without putting too much pressure on the compartment itself. The most important part, imo, is to have a correctly sized vent line that matches or exceeds the flow capacity of the fill line.
I'm sure I'm simply not understanding the logistics or layout of the Classic (not older) Supra boats, and would certainly defer to Mikey's recommendations.

[Memmer99]

Well my fill/drains are 1" and my vents are 3/4". We'll see how the test goes. Hopefully Cali. gets a break from the rain on Sunday.