View Full Version : Wedge on a Moomba

David Davidson
06-10-2010, 09:12 AM
I was surfing behind a Malibu my friend owns this weekend and all I could thing about was what a wedge would do on my boat. We had the wedge down, 500 lbs. of ballast in the corner, and 400lbs. of human ballast one side of the boat. At 10.5 mph it threw out the biggest surf wake I have ever seen. I have heard that the transom on the Malibu's are 3/4" thick to take the load of the wedge. I am serious about trying to make one to put on my boat, but I don't want to start drilling holes and find out that my transom is too thin to take the load. I would assume that all the load from the wedge is pretty much straight down and only the drag of the hydrofoil would give any actual torque on the mount.

If you guys have any input on this subject it would be greatly appreciated. I found one old thread from 2008 that talked about it although it had no final result posted. The boat is a 1998 Mobius.

I know I could just load my boat down with ballast but it is a small boat and I hate having to deal with bags every time I go out.

06-10-2010, 09:18 PM
The Malibu Wedge: just do a search and you will find that it is the greatest thing every or the greatest mistake ever.
Advantages: easy to use, fast to set up, no extra load in the boat to make it sink.
Disadvantages: Boat must be designed to handle the extra stress on the boat. Hit a stump and there goes the back of your boat!

If you search hard enough, you should be able to find a used one from a wreck/destroyed/salvage boat. If you mount it on your boat, beware. First, you will want to reinforce the whole transom. Second you will want to find shear bolts to attach the wedge to your boat.
You need to take measurements between the exhausts to see if there is enough room on your boat to even try. The last thing you want to do is modify a wedge to the point that you have no data if it will work.

David Davidson
06-14-2010, 10:00 AM
I can't find a wedge for under $600 so I guess I will have to fab a adjustable one. I think this will make a good winter project.

06-14-2010, 03:44 PM
Do even more searches and you'll find a lot of damaged and broken wedges. They are notorious for breaking as you add stresses of surfing and extra ballast. The Malibu is designed to handle the stresses with a lot more than just 3/4" transom material. A Moomba is not, even more so for your '98. I'd consider the power as well, a wedged Malibu has plenty of power to handle the load.

Ian Brantford
06-15-2010, 10:16 AM
I would put this in the same category as putting a tower on an old runabout that was never designed for it: don't do it. You might get away with it, but there is a pretty good chance of the whole thing just ripping out.

I would never trust myself to remember to bring the wedge up before entering shallow water... such as every time I return to the marina.

David Davidson
06-15-2010, 12:35 PM
I have also come to the conclusion that it would not be worth it. I will just upgrade when I sell it, in a year or two. Just have to deal with ballast bags till then. :(

06-23-2010, 09:39 AM
The folks at Switchblade put one on an old Supra DD. It's even bigger than the wedge. I have one on my boat but it was designed for it. The kit does come with a large mounting plate to distribute the load. Expensive at $4k, but can be had on ebay for $1500-$2k. Shear bolts are part of it in case you hit something but still scary about dragging that thing around the lake.

Bad: driving is less responsive, MPG/MPH is a bit worse, expensive, hope you have a deep lake as I won't run it in shallow lakes.

Good: it kicks butt at shaping the wave on the fly. adds a few vertical inches to the wake (really about 600lbs ballast equivilent). turn it on and everyone says Wow. No bowrise on takeoffs.

Not worth it unless you have a 'no ballast' restriction on your lake, or really want to have the best wake possible money no object.