Sea Ray 245 Cuddy Fish (1983)

[Barry_CF]

Thanks WP.

I'm mainly thinking about weight and weight distribution. Best I can tell the Mercruiser has a horizontal COG of just about the back of the engine when the stern drive is accounted for. Weight is something around 900 pounds. I'll replace that with a bracket and outboard that will probably come in around 700 pounds, so I'll lose a couple hundred, but shift 700 roughly 2-3 foot back. I should be able to move my batteries pretty far forward since I now know there is plenty of room and height under the sole for them. The gas tank is about as far forward as possible now unless I change the front bulkhead location. All this is going to require the sole to come up anyway. The sole would be supported in 4 places if I hold to the current design, one on each side of the gas tank and then each side. The worst case span wise is about 30 inches.

So, just wondering if I can shed some weight with a new floor, which is impossible to know unless I know the weight of the existing. I can get that when it's removed. I can use 1/2 or 3/4 plus the glass and epoxy. I just don't know what is enough...

[Fuzz]

Have a water hose and a fire ex close by and then cut the deck with a 4 inch grinder and a thin cut off wheel. I have cut a lot of glass recently and not had any problems doing it this way. If that scares you use a skill saw with a carbide blade. The multi tools are great but there are better choices for this job.
For your deck I would order 7 foot sheets of NidaCore from BBC. One or one and a half inch thick. I do not think the cost will be any greater and you will get a stiffer deck. Thicker=stiffer.

[Barry_CF]

I think you are correct Fuzz, and I appreciate the guidance. This afternoon I decided to get the seat pedestal/mounts out of the way, and I knew the port side seat mount would have a big hole so that I could see precisely how the sole was made. I'm not sure what made me think there was no plywood in the construction, probably the gas tank cover, but that was wrong.

Pictures, first showing the area I remove the seat mounts and the 2nd showing a close up of the sole construction. It measures 1.25 inches thick, 3/4 plywood and glass a quarter inch thick on each side.

I understand the stiffness increasing as we increase the distance between the glass. I'll have to get off the old first, and at this point I'll plan to remove it all, and then I can see what will work best. I did not realize the price of the Nida core was competitive (or better) than plywood so that's what I'll plan to do. What would you suggest for the glass layup on each side?

I assume that you glass one side of each sheet, then butt blocks below plus the cleats, and then glass the top after it's in the boat?

Thanks greatly!

[Barry_CF]

I forgot to add, there was no sealant of any kind present on the seat mounting plate holes. The port side, which is a removable seat, was the worst since the hole was cut and no sealant around the cutout. From the day it left the factory every time the sole got wet there would have been water soaking into the plywood in those spots. There are a few other screws that have no sealant, like the ones that hold metal angles screwed to the soles to attach the walkaroud supports on the bottom along the sides. I'm guessing that is why the rot has occurred.

[fallguy1000]

Plywood sourced locally is okay. Any composite core might require edgework. Plywood decored and recored is the ideal, but most are too lazy to recore or even epoxy seal edges.

Anything requires at least one layer of 1208 in epoxy to prevent ingress.

I'd go 1/2" plywood or 18mm core or 25mm honeycome with veil... the nice thing about ply is it doesn't require inserts for screws, but this is where guys get lazy and done decore and record with thickened epoxy..

[Fuzz]

You have the right idea about how to lay your deck down. As far as what amount of glass to use that depends on a couple of things. What bracing will there be, how far apart, what thickness is the core, what resin will be used? The gillnet boats up to 45 foot around here are using 1.5 core with two layers of 1708 each side. This is done with poly resin. Those are work boats and might have 10,000 lbs stacked on them at times. You will not need to be that heavy I am just showing what works for them.

[Barry_CF]

Fallguy, Fuzz, thanks for the reply's.

I have to check my gas tank clearance to determine the thickness of the sole that I can go with and clear the tank. It's raining today or I would have done that already. I'm thinking 1.5 plus glass is doable, maybe a single layer on the bottom and two on top. I could also probably raise the sole a small amount if need be. Since the original is 1.25 total I would think even 1 inch nida core and glass would work. But I would prefer to go thicker if there is room.

Thinking ahead to the balance of the boat, if I have it correct, the Mercruiser Sterndrive engine/transmission weight is perhaps a shade under 1000 pounds with almost 700 of that engine weight (heavy manifolds). Assuming the engine horizontal COG is near the center of the engine, just back of the envelope calculations and rough measurements place the total COG at the rear of the engine, maybe 10 inches forward of the transom. With the bracket weight and an outboard of 250hp, I'm coming up with a total weight of approximately 700 pounds. That 700 will have a horizontal COG that is roughly 30 inches further aft of the original. I have two batteries, about 120 pounds, located at the rear next to the engine, that I should be able to move forward, at least 120 inches, probably more. the battery move has 4 times the effect of the engine move (120 / 30), so in effect I offset the COG engine move by a counter move of 480 pounds (4 x 120 pounds). While I know dimensions are not yet exact and the actual COG currently might be off, it would seem to be fairly easy to re-balance the boat, especially since I shave nearly 300 pounds on the powerplant and possibly more in the sole replacement.

Any error in my thinking that you can see?

Thanks!

[fallguy1000]

The easiest way to redo a sole is to keep a 2" wide section of old sole around the outside and set the new on top.

I'll keep this reply short for conversation.

[Barry_CF]

So, in that case, it's going to be higher by the thickness of the new sole, right?

[TomW1]

In your COG calculation don't forget to take off the weight of the stern drive that was hanging off the stern before you took it off. 200lbs by whatever length helps you. Remember the COG of the boat is measured from the helm or slightly behind it on most boats. Good luck on your project. Tom