i own a 93 sea ray ski ray 185 spitfire, similiar to the mastercraft 190. how will i know if i need to reinforce the monster tower backing plates when i install it? or should i do it no matter what?

I'd do it no matter what. Just MHO.

I installed a monster tower on my 91 Sea Ray. Being lazy I didn't reinforce the tower and rode that way for a few months. I didn't see any problems. Being an older boat I decided later to thicken the fiberglass on the underside of mounts. I don't know if it made any difference but it was worth the peace of mind. I say better safe than sorry.

Read the instructions on Monster tower and it will tell you if you need extra backing. <BR> <BR><a href="http://monstertower.com/support.htm" target="_blank">http://monstertower.com/support.htm</a>

I have a 1983 nautique, and I am already starting to see spider cracks after a year installing the tower. Do it no matter what, use epoxy resin also. I am going to do it so the cracks dont spread. They are only an inch long, but they will just keep growing. Remember, these boats were made when towers didn't exist on ski boats, so the top decks aren't really built for it.

how do i reinforce it? do i just put coats of fiberglass resin on the bottom side where the mounts will go?

Not just resin but resin and glass, resin and glass, etc

monsters site says to use plywood and glue it on the back with marine adhesive. so i think im going to do that and then use fiberglass cloth and resin and do a couple coats. with this be enough for all 4 mounts? and how big should the reinforcements be? the same size as the backing plate or larger?

As big as the room around the area allows. The larger the area the more dispersed the load will be. I think I have 4 X 6 or 4 X 8 size backing. <BR>Go with what monster recommends or a little more for safety. In this case any additional really wont be overkill. You cant imagine the loads transferred to the hull when a boarder is pulling, with boards in racks, tower speakers and then you cross someones wake coming toward you.

Bob, did you just use wood, or did you use fiberglass cloth and resin along with the wood?

I bought my boat with the tower already installed. Don't know if it's reinforced, but no cracks...<img src="http://www.wakeworld.com/MB/Discus/messages/65921/458234.gif" alt="Upload">

i have that exact boat.

They are actually metal backing plates slightly bent to match the hull shape.

I just did this on my 96 Centurion. I put some layers of glass behind the mounts then I put a 1/2 inch plate of aluminum 6"x8" over that then glassed that to the boat. I also threaded the holes in the plates so to have the bolts pull it into the boat with nuts on the back side of the plates locking everything into place. Maybe over kill but I just put up 40lbs in speakers and don't want to hurt the boat.