in reverse water comes over transom

When I put the motor in reverse water comes over the transom into the boat. Especially when pulling the boat off the trailer at the ramp.
Any suggestions..this is a g3 with pontoons...manual jack plate....also seem as though I have to put my back tires into the water to float the boat enough to get the weight off the trailer...or give it a lot of power ...thus getting water into the boat...this has happened at two different ramps...also I am a new owner of this used boat. this is a 1756 tunnel with 70hp.
thanks for any help

Do you only have this problem at the ramps? What happens when you put the boat in reverse on the lake when the water is calm?

As far as you problems at the ramp consider trailer Slides-
I have these for my pontoon and it helps quite a bit loading and unloading, I don't have to back the trailer as far down the ramp and that is a good thing when the water is cold especially -
http://m.basspro.com/Bunk-Slick-Boat-Tra...OSSSELL_PRODUCT

i never had that problem till i got this boat but i have a bilge it just pumps it out to get around it though i have a long bow lines tie it off to the trailer back up and spike the breaks then pull the boat back in on the side of the ramp and go get the truck if i am buy my self it i have someone with me i have them back down and spike the breaks to pull the boat off the trailer. i get it also if out on the lake and give it to much gas it will come in side i usr dont do it anymore

Too much weight in the rear of the boat try relocating the battery or fuel cell towards the front if possible

The ramp you are using is not steep enough. Sometimes I have to put my front tires in the water to get my boat in. The ramps at Gvine are pretty bad sobIbam use to this.

I have a 1650 tunnel hull aluamacraft with pods on the back, one thing your gonna learn is reverse sucks, and so does makeing turns....tunnel hulls definitely have their drawbacks.

get a splash guard for the boat they make them for boats low in the back .....

Tall(ish) trailer? Shallow angle ramp?

if your wife weighs 300-400 lbs, have her sit in the front

well i am screwed my wife is 5'1 95lbs and i would not want to relocate my 40 gallant take under my cancel to way were els on my boat the the OB it he has pontoons on the back is partly the reason my boat just has a low transom but a great build pump

my a small big pump wire it up and let it uck up of the floor when your don all the hose back in and turn it off it wont salve the water coming in the boat but it will keep your feet dry

She's just big-boned, dang it!

Thanks to everyone for your help. I think the first thing to try is boat slides, then a splash guard....then if that dont work I will be back for more info.
thanks again

LMAO snowyriver