Jetted Piling Help Requested

Some non-technical partners and I have a floating fishing cabin on the Texas Gulf Coast near Matagorda Island. We have had much trouble with the minimal jetted pilings we've installed getting worked/pulled out by Norther storms during the spring months and the cabin ending up high and dry on the island adjacent to it. Obviously, the single pilings we installed have been inadequate for the lateral loads imposed by a) winds pulling on the steel cable draped around the pole or b) dynamic wave loads that cause the cable to yank on the piling with the full force of the 9000# cabin. The cable is about 100' long and is attached to the cabin on two corners of the 16'x24' cabin.

We've installed two pilings to date: 1) a 8-10" treated wood piling about 20' long, jetted about 10' into the saturated silt and fine sand bottom and 2) a combination piling consisting of an 8" 20' galvenized pipe (tinhorn) with a 3" ODx30' drill pipe in the center and concrete in the annular space, jetted to about 15' below bottom. Water depth is about 3.5-4.0 feet. The wooden pole was wallowed out by a storm in 2001 and we haven't seen it since. The combo piling is listing at 20-30 degrees to vertical, but is still intact. It will have to be jetted out to restore it to vertical.

We are limited to manual methods that can be accomplished by 4-5 weakling professionals and a couple of 22' fishing boats for piling installation, as pros will charge as much as $10K to install a dolphin.

My current plan is to install a 3-piling dolphin, including the current listing one, using a 3" trash pump and PVC stinger jet pipes to install these. After installation, sand will be pumped back into the conical holes from a distance away to backfill the holes to grade. That's a trick I didn't learn until recently.

Any suggestions on a) technique or b) an easy way to determine adequate piling number, type, grade, or depth? Jetting is definitely the cheapest and most accessible method of installation we've found, and my choices of pilings now include 1) treated wood pilings (20' long) or 2) helical screw anchors. We can't use a hydraulic power unit and impact driver with the latter, because the power unit is over 1200# and too heavy for an ordinary fishing boat. It should be possible to jet the screw anchor in though, I believe. Other threads have suggested that the helical anchor won't support as much lateral load as a larger diameter piling. I'd like any thoughts on that issue.

The design storm would be about 75 mph and the area of the exposed end of the house is about 200 sq.ft. Again, the house is about 9000#.

Thanks for any help on this you can provide.