1972 Keel Up Restoration

I'd leave the transom you have. With the strength of the coosa boards, the "knee" supports under the splash well, and what looks like a higher splash well bottom, you will have plenty of strength. I have a pair of straight 6 merc 150's and used 2 sheets of 3/4" plywood plus glass. Total thickness was same as original boat and it is solid as a rock.

 

That is good to hear. When I started this project and took everything out of the hull shell I was left with a 1/8" stern. Then I added 3 1/2" coosa boards for another 1.5". I plan on adding a bit more glass to the transom and stringers and knees to tie it all in structurally. The splashwell will help too. When I am done the transom will be a shade under 2" under the splashewell but be slightly over 2" above the well. I will tie in the well to the rest of the stern because Jim said the structure is tied into everything. That makes engineering sense to me for load distribution. I just want to fearlessly firewall the throttles and not worry about it.

 

You are going to have this boat a long time. Do what ever it takes to make you happy. I assume you will put a plate on the outside?

jim

 

Glad to see you are back on the job. Looking at your rebuild I almost find it funny that you are worried about strength in that transom. When you drop the deck on and tie the splashwell in to what you have so far, the box section and the knees as well as the center reinforcement, epoxy and coosa board, I would call it bomb proof. Nice work, now 'git er done'!

Have you decided on a deck color yet?

 

I was not planning on a plate on the stern. The deck will be red like the Dyne I drove for the ski show in the mid 70's.

 

tj-
I wanted to see how your build was going. I think I speak for many Hydrodyners saying we are looking forward to the results! I am curious as to what you plan on powering this monster with, or if you've purchased motors yet? I know you had a thread out there discussing power options and you were leaning towards 4 strokes. Unfortunately I can't speak to an 18' with twin 4 strokes, but I have had quite a bit of experience with our club's twin 20'. When I joined the team we were running twin 4 stroke Yamaha 150s. The driver of the twin personally owned a 20 with twin 150 Merc Optis, so he was in a good position to make a direct comparison. I remember him being fairly displeased with the performance of the club boat with the Yamahas, particularly in the high speed range. It seemed to have plenty of torque and pulled well for the big group acts, but it seemed to run out of steam when pulling barefoot acts. We have since been running twin 150 Evinrude Etecs and have absolutely loved the performance. If you're considering 4 strokes I would be less worried about the weight and more about the performance. Of course using the boat simply for recreation, how often would you be pulling 8 footers? Fuel economy, exhaust (although personally I LOVE the smell of 2 stroke exhaust haha), and noise (although if you haven't ridden with an Etec I would recommend it, they are extremely quiet for a 2 stroke) are all valid considerations, especially for a family boat.
Looking forward to the future of your build~~

 

I am going with the twin Merc 150 4 strokers. I have a 115 Merc 4 stroke on the pontoon boat and love it. I already have about half of the smartcraft gauges and the modified twin throttle/shifters (I posted a separate thread "dual trim for side mount Merc controls" on the build of the throttle/shifter - under restorations). I also have 1 19" prop and for starters will get another. I am thinking about going to a pair of 23" so I can cruise at ski speeds at 3000 rpm and enjoy the fuel economy and lack of noise. With the twins I don't think hole shot will be an issue and I wont be pulling any pyramids. I hope to get up to the cabin/shop in the next 3 weeks and do some more work and will of course post my progress.

 

This is the best pic I have and it does not show what I am planning on doing....

It looks like I will have to put a slight incline in the floor at about the dash panel. I plan on mounting the batteries and battery cut-off switches just under the deck in the center leaving leg room for the driver and obsever - which would be on that slight inclined floor section.

My question is this: How flat do the batteries have to be? If I mount them on that slightly inclined floor and combine that with 2 heavy motors on the stern the boat will amplify that incline just sitting in the water.

My plan is hopefully in a couple of weeks to go up to the cabin and finish the forward floor. There will be a raised platform just ahead of the batteries for the gas tank.

 

AGM batteries (like Optima) can be mounted like that.

HOWEVER, they have a low internal resistance. I have heard that they are not compatible with some outboard charging systems. You need to do a little research with the manufacturers.

jim

 

Jim,
I run the Odyssey Extreme ER-40 AGM battery in my Trick Cat tunnel hull with the 300XS Mercury.
It only weighs 27 lbs. and is claimed to have 3 times the life of a standard battery. These batteries
evidentally have no problems with the Mercurys charging systems. ( I do keep it on a battery tender
when it's in storage.)

Bob