yep. Noone else in Australia to ask and this forum is really looking after me so far, so here goes.

Other than getting the boat on a plane, what are the huge tabs used for? I keep them right up now and use the trim on the drives.

I've down tabbed when in a following sea and it helped keep the nose down.

Is there a purpose for getting speed up or stability?

I've had it up to a shade over 80mph but it seems to go much faster I'd have to hold it flat out for a long time. I'm wondering whether the tabs can help. They are the 380 K planes.

Also, I've noticed some small stress cracks in then engine bay just behind the back seat where the wall joins the floor in front of the motors. My Seadoo Speedster has mega stress cracks in it. Are they normal in the engine bay?

Cheers

I've never got anything from my Kplanes either, except to push the bow down to split open rough seas. The local speed freaks around here say to leave them all the way up for speed and I have to agree with them. I'm not sure about other brands, but it seems like you have to wait a long time to get the last 5 mph out of a Donzi. Be patient is all I can say, cause it will come. Be careful about loading your cabin with a bunch of junk, because it will add a few hundred pounds exactly where you don't want it (in the bow).

Oh, the cracks are totally normal. Mine has them too, and they grow and multiply. No worries (unless they start to cry - - leak :-)

thanks for the advice... much appreciate it

They will keep the boat running flat in rough water. They will also compensate for a list. Get 'em up for top speed runs.

A 38ZR w/525's you should see 88 mph with tabs up and drives trimmed. Maybe 90 mph depending on props. Rough water tabs down to get the nose down and tuck in the drives proportionally.

To elaborate a bit on the tabs. With tabs up and out of the water, the hull will ride fairly level at most speeds, maybe slightly bow up. As you've seen when you apply tab it pushes the bow down. More tab=more bow down.
When your in conditions needing to apply tab like rugher waters, you'll want to run the drives roughly level. To get the most bow donw, put tabs down and drives in.
However be very careful using speed, or turning, or both with alot of tab down in that stepped hull. The counterpoint to pushing the bow down is a lighter aft. Thus inviting a spin out .
In some hulls running tab slightly above flat can actually gain speed fomr no tab at all.
With the boat on the trailer, level the tabs with the hull, and put the drives at exactly 90 down. Then mark your dash indicators with tape or something so you have a reference point when driving.

You should give your dealer a call as I'm sure they know that boat very well and are very willing to help.

thanks again everyone. I think we've got it mastered now. What an amazing machine. 60mph in comfort across a 4 to 5 foot chop. Wow !

I agree

anyone know how the head pumps outside? With the boat on the hardstand, I flush the head but cannot see where the discharge goes.
I found a ball valve in the engine bay on the starboard side, right near the seat. It is closed.
There are seperate fillers in the engine bay. Port is fresh water, starboard is waste.
I've tried opening the ball valve and flushing the head but still don't see any external discharge from any of the outlets on the outside of the boat.....