loaded zodiac troubles
details on the setup:
1986 zodiac MKIII GR 15'-5" Just put a new transom on it by Alaska Raft and Kayak. New eurethane bottom on it by Alaska Raft Connection. Boat is in very good shape. Has a new Keel. running a 1985 Susuki 40hp on it.
Built a wodden bow box that weighs 40 pounds empty.
Put another 60 pounds (anchor, tools etc) in box.
Mounted a 26 gallon fuel tank on the aluminum floor towards the front
With a full tank of fuel, wife and dog in front and a drybag with coats etc. on the bow the boat really wants to buckle if I get going over 14mph or so.
Yesterday out in the passage of whittier it buckled up pretty bad. I trimmed it nose up a couple notches and had to come down one. Now it is on the 3rd notch from the transom.
If the wife comes and sits on the back with me then it seems to do much better and almost no "porposing" occurs.
Reading some of the latest zodiac threads I see some of these boats loaded to the gills with a lot of the weight up front....do you guys experience this porposing on these loaded boats?
Any ideas for what I should try next? Maybe I just need to learn the boat....
I built a similar box for my 13.5' Achilles with wooden floorboards, pushed by a 25 HP 2-cycle Yami. It buckled till I moved the box back to straddle the floorboard joint and take some of the flex out. I've had three big guys in it and extra gear in the box (including my 6hp 2-stroke Yami for backup). No more porpoising. Still get some flex as it comes up on step, but once it flattens on step it stays that way. If your setup won't let you shift the box back to straddle that joint, I'd look at other ways to stiffen it.
Those old zods like a lot of air in the tubes. I used to have to pump mine up as tight as I could to get it to not buckle sometimes. Plus is ran so much better in rough water.
I am thinking that it is more of an air issue too. In talking with ARC they told me more air too.
The box has two 2x4 runners (to clear the valve on the keel).
I don't have a lot of faith that the old pressure guage that I have is very accurate.
That's sounding logical. I had assumed your tubes were plenty rigid, but if not, that explains it pretty well.
Also keep in mind that you can have lots of pressure in the tubes before you put the boat in the water and then the cold water will decrease the air pressure. So you may need to add air once you're in the water.
The air outside was actually a little cooler than the water was. Either way I should have pumped up the tubes.
Have heard that you can give these things all you have with the foot pump and not pop them....that may be my new pressure guage. Thoughts?
What do you guys use for pumps? I am using what appears to be the original that came with the boat and it is starting to leak with wear......
Yep. Toss the pressure guage. If you have the bellow type foot pump, pump it up until you have to switch to the high pressure side then pump more until you can't feel your legs........ Actually, if I was going moose hunting with mine, I would top it off with my air compressor for that little extra. Man she ran good like that. Sure wish I had kept her.
I use the compressor at home to get her most of the way up but am terribly afraid of popping it......so I usually top off at the put in.
I don't have a high pressure side on my pump. it has a fill and an empty port..this is the old style bellows that I think is original to the boat.