View Full Version : wat is moomba doing?

04-15-2007, 06:02 PM
i've had alot of inboard boats, but this is my first wake boat. There is no water shut off on the main hose for the water intake? what happens if i burst a hose in the middle of the lake?

04-16-2007, 12:01 AM
That's weird. My '03 Mobius and my '06 21V both have had shutoff on them.

04-16-2007, 02:12 AM
The mechanical types may correct me on this. The water flow into the engine is controlled by the raw water pump and the engine water pump and shutting off the engine will stop any water flow past the raw water pump since it is a positive displacement pump which means shutting off the engine shuts off the water supply. The raw water hose is vulnerable up to the point of the water level around the boat. So the main issue would be a leak at the connection in the bilge where a valve would be practically useless. The bottom line is it is not needed and may have created problems for some people who may have shut off their cooling water supply.

04-16-2007, 06:24 AM
True, but I believe the line between the water intake fitting and the the raw water pump would be below the water line. If that line ruptures and the boat begins to take on water it will sit lower and lower in the water causing more water to rush in. At some point, the only bouyancy will be the foam in the hull and by then it's a little too late.

04-16-2007, 09:57 AM
The same could be said for the hose between the intake and any type of shut off valve.


Unless they build an intake with a built-in shut off, no additional valve is terribly more "safe".

Throw some pipe tape and hose clamps in your boat tool kit and you are much safer!!! Also any boat without a manual bailer is asking for trouble. $20, and it acts like a bike pump - even kids can do it. Actually , most manual air inflators (for tubes) can be used in an emergency for bailing water.


04-16-2007, 10:03 AM
If she sinks I will make a quick call to the insurance company and get a new one on order! (I am sure this would work at least once)

04-16-2007, 10:51 AM
well im always down for new boats! i guess im going to have to cll the dealer

04-16-2007, 10:13 PM
Prob a good question for SC engineers. I can tell you that the intake hose is pretty heavy duty and reinforced with wire. I know cause I installed my strainer. And if its rated for the pump output, its definitely good for the suction. Having said that, I check all hose connections as part of the annual pre-season pm list. The ballast system on my '05 has a shut off valve.

04-18-2007, 02:56 PM
I believe this is a problem, also. The intake tubing is strong, but I recently had my flush-pro break into two pieces while on the lake. This is installed just after the main intake through the hull and sits low in the bilge. I can tell you that water came into the boat FAST. A shut-off valve would have at least stopped the flow of water into the boat and allowed for a safe tow home. I installed a new flush kit but now check it and the strainer regularly for cracks, etc as I think they are a weaker link than the tubing.

04-18-2007, 09:15 PM
Every time you add a component to the raw water line, you add a potential failure point as you saw with the flush kit. My boat does have the transmission cooler between the intake and the pump and that is it. The system needs to be checked periodically especially the hose connections as they can loosen up. I would expect a failure of the raw water system to be a small leak in the hose or connections that the bilge pump could cover not a catastrophic failure of a component. Unfortunately, everything in life has a statistic associated with it. The manufacturer may claim that the flush kit fails one out of a million and you happen to be the one in a million.

The raw water supply line is a critical system for cooling and the risk of flooding the boat so you must minimize the risk of failure by minimizing the number of hose connections, visual inspections of the hose/components and if you do add components to the line ensure the product is a good quality part with an excellent operational history and make sure the part is installed per the manufacturers recommendations and tested after installation. Long sentence there but after all that was said last year, I did come across a small nick in the line on my boat where the alternator pulley rubbed against it. The nick was only in the outer rubber layer and I accepted the risk that it was OK, I tie wrapped the hose away from the alternator and I periodically check the hose for any further degradation. Having a shutoff valve introduces more problems than it solves with an additional failure point but also the valve needs to be exercised periodically to ensure silt and debris does not seize the mechanism.

I'd be interested in knowing what you did after you discovered the water coming into the boat were you able to pull the boat out , beach it or do a quick fix.

04-18-2007, 09:45 PM
Fortunately I was very near my dock (maybe 100 yards away) and was able to idle over and put the boat up on the lift. Had I been far away, this could have been a disaster. Obviously the engine is not getting enough water and will overheat, but sitting still you will sink! I can tell you that the bilge does not keep up with the amount of water coming in in that situation. :shock:

04-18-2007, 10:38 PM
Close call! I think, if you have someone to drive the boat, a shirt will suffice as a pipe patch. You can back it up with a glove or something to get you to the dock and ideally onto your trailer.
Zabooda, good analysis. Sinking is not an option given the water temperatures around here. I 've also found the same problems around the alternator. The hose to the tranny cooler can get rubbed by the pulley but is protected by a piece of corrugated plastic. The hose from the v-drive cooler to the impeller gets nicked by the alternator bottom support bolt. I agree routine checks are necessary and effective.
Last winter, I ended up winterizing my boat myself. After what I found in the v-drive and tranny coolers, I really appreciated the strainer I put in.