Pete, I know you can answer this question but I'm not sure if you're in town or not.
Tell me about adding fittings to ballast bags. Where can you get parts, what's the process like (no smart a$$ comments, plz) and how strong are the completed fittings.
I understand that most people who're trying to hide their forward sacs use Side Sacs under the bow cushions with mixed results. At best, they're getting like 400 lbs up there because you can't fill them.
Have you seen the waterbed tube sets? The tubes can be ordered as replacements for waterbeds using such things. The ones I've been looking at are 14.5" wide when empty/flat. To me, this means a 28" circumference, or a diameter of 9" when fully filled. There is a single fitting on the top of one end. The bags work out to 28 pounds per foot per tube. I think that two tubes will lie next to eachother in each bow seat area, and can be ordered 60" long.
Four tubes 5ft long at 28 lb/ft works out to 560 lbs. More importantly, it's very far forward and off the floor. This much weight up there will preserve balance with a big sac in the trunk (Big Bump fully filled - 750 lb, or the mondo Fluid Concepts sac mostly filled - 850 lb). It just so happens that the balance is nearly identical between the Big Bump in trunk and the custom v-drive sacs mentioned above (1150 lbs).
Based on rough guesses and a little empirical evidence, here are balance calcs with four 5' tubes fully filled in bow:
1) Custom v-drive sacs: 1710 lbs ballast, boat center of gravity 2.9" farther forward than normal.
2) Big Bump, uncovered and fully filled in trunk: 1310 lbs ballast, boat center of gravity 2.6" farther forward than normal.
3) Fluid Concepts or custom sac in trunk, filled to 950 lbs: 1510 ballast, CG at it's normal location.
The forward CG is probably a really good thing for driveability, bow rise, etc. The one time my boat's been heavy was 1050 lbs shifting the CG aft around 3". Bad bow rise.
If I could install sac fittings on the ends of the tube sacs, I believe the battle would be won. I'd tie each side's sacs together and plumb them back to the back of the boat. In effect, the five or six sacs become one, with both fill and empty pumps at the lowest point in the system. I'd orient the standard fittings on the tubes forward and upward in the bow and connect them together, then through a restrictive check valve and into the existing through-hull.
The aft sacs would be drained and filled through fittings near their lowest points. With the custom sacs, this is easy; with Bump in the trunk, I'd like to add a fitting in the center, bottom of the sack (down by the rudder's tiller). The top fittings of the Bump or custom v-drive sacs will exhaust overboard through a restrictive check valve as well.
The exhausts will allow the bags to burp themselves and will indicate when bags are full. The restriction will ensure that both forward and aft ends of the system fill. The check valves will ensure that air doesn't enter the system when draining (which could break the drain pump's suction.) Since the bow sacs are low and the aft exhaust/drain is high on the gunwhale, I don't think the sacs will siphon/self empty while underway.
Based on Pete changing his mind yet again (you da man ;-) you'll see a change from solenoids to simpler cable-actuated valves. Will probably connect switches to either the valve actuator handles or to the valves themselves which will energize their associated pumps. Manual actuation can't be such a bad thing, right? Pull the valve handle (up by the helm) and the pump turns on.
Might not need the exhaust/bleeders, but they make sure for sure, ya know? Comments?
By the way, gethighsports.net (home of the Big Bump) is selling these huge sacs for $55 right now. Pretty damn good if you ask me. In all likelihood, I'll just grab a pair of these bags and do it old school for a while.
