Avon Searider Water Ballast system

[westlajay]

I recently acquired an Avon Searider 4.0. How does the water ballast system work? I see a threaded fitting in the lower section of the stern (transom.) Do I simply open that fitting and let the boat do the rest?

[Nos4r2]

That doesn't sound right. Post a pic of the transom.

[Sailmaker]

As just said that doesn't sound right.

The basic system is a large round hole 5 -6" at lower centre of transom plus a couple of small round holes 1" approx at the forrard end on either side of the hull adjacent to the stem. At rest the lower hull floods and makes it very stable but on the plane the water flushes out of the transom thus lightening the boat.

Sounds like someones modified your boat?

[westlajay]

Here is the shot of the transom in question.

[mike-stgt]

Hi there.
the flooding hull works at lower speed and stop. In the front, just under the waterline , there is one hole of 1 inch in the hull. In the center of the transom,
just at the keel, there is a hole of 4 inches.
The hull has a seperate chamber inner the keel from front to back.
In stand, the water is flowing through the big hole in the back an gives a
plus of 700 pound water to stabilize the boat. In acceleration , the nose is comming up and the water is leaving in the back through the 4" hole and
breathing air in the 2 front holes. In decelleration the nose is commong down
and the front holes into water. So it is filling in decelleration.
I hope to have it declared to understand.
I have closed mine, because it needs a lot of power to come up from stand
to planning.

Salve Mike

[Tomas]

I looked at the photo and don't recognize what I'm looking at. The other posts relative to the water ballast system are accurate. Some like it, some don't but I can assure you that when laying to in a seaway, not corking all over the place is a real benefit. Landing a fish is sufficiently difficult into my 4.7 without bouncing around more than necessary. I don't really care that it takes extra effort and time to "get out of the hole".

[Nos4r2]

Originally Posted by westlajay

Here is the shot of the transom in question.

Your flooding hull has been closed off. Do you still have the holes in the bow? If you do you need to block them too-and that small hole needs a screw in bung.

[9D280]

Originally Posted by Nos4r2

Your flooding hull has been closed off. Do you still have the holes in the bow? If you do you need to block them too-and that small hole needs a screw in bung.

.....or get your holesaw out and reinstate the 4" hole at the transom!

I guess it depends what you want it for. The stability can be useful as Thomas says, but if you do a lot of stop - start then it can also be a pain in the bottom. Once the hull has emptied of the ballast water it behaves like any "sealed" hull. The only real difference is that it takes a bit longer to get up on the plane. Also with the ballast system it sits a bit lower at rest- good for rescue work (and I guess fishing?) as you're closer to the surface to pull people / tuna out. I had an SR4 with a 25 on the transom. Took about 20-30 seconds to drain & plane, but as it mostly was used for cruising it really wasn't a problem.

In short you either want a big hole at the back and the two small ones at the bow or none at all! Just remember that if you do reinstate the rear 4" hole to seal the perimiter properly or you'll get a floppy transom.