Repowering 18' Potter

[Bushwacker]

Originally Posted by T-MAN

. . .
I just repowered my '76 18' with the new Yamaha 115 a couple of weeks ago. I did not move batteries under the console and wish I had plus I had put a 40 gallon Moeller which I don't regret. She squats a little but not too bad.

I decided before I did anything else I would try putting 50# bag of sand in the front and it helped. I had a Merc 2004 115 hp and I like this new one a lot better.

Adding ballast is not the best solution. I'd suggest moving the batteries to console and maybe adding 20' of chain to your anchor line, which will dramatically improve holding power of your anchor. And maybe consider adding trim tabs. Any of the Moesly designed SeaCrafts will plane at about 12 mph if balanced right. Other bandaids you could consider to help the stern-heavy condition would be an AV plate fin and a stern lifting 4B prop.

[BocaSeacraft]

I'm still researching the F70 and its use on similar weight boats to my 18. Boston Whalers Montauk 170 weighs in dry at 1400# and the base motor on that boat is shown as a 60 Merc. 90 is max. The more I read about Seacraft 18 and 20' boats and a lot of the advice on this forum stresses weight and center of gravity, etc. If the boats are designed to plane out at 12 mph if balanced correctly, the additional 47-75 pounds of weight (over the design weight of 300#) seen on the latest 90 and 115 four strokes is kind of a big deal. Maybe it's not a big deal if added to the center of the boat, but hanging out over the transom... I'd really like for my scuppers to be above the water line as designed. Maybe I'm crazy but I'm still leaning towards the 265# Yamaha with like a 13 or 14 pitch prop.

[BocaSeacraft]

So, I've decided on the Tohatsu TLDI 90. The weight is decent at 337 and my research on the web and talking to some marine mechanics has shown the motor to be fairly bullet proof. I was liking the Suzuki 90 but found the dealers around here to be lacking in the follow up department. Like, nobody wanted to give me a price after several attempts. the Tohatsu dealer was the exact opposite. He spent a bunch of time with me running through all the details. I wiol report back after the motor is rigged and run. Thanks everyone for all your input, knowledge and advice. If anyone out there runs a Tohatsu 90, it would be great to know what prop you are running. I'm thinking 13.25 x 15 Stilletto.

[Beaver]

Please give us a report when you get your motor on.

Thanks.

[fishfullthinking]

BocaSeacraft once you get the boat setup I would love to go for a ride. I have been looking for 18 but never actually rode one. I will bring your beer of choice. Cheers!

Fishfullthinking

[JayN]

Hi Boca, if it were my boat, I would go with a motor in the 115HP range, maybe a little bigger. like up to 150HP. It's nice to have the extra power, in case you need to carry extra weight, like dive gear, big cooler, or extra people. You don't need to run WOT all the time, and when you do it should get up and go. I have a 1971 20' CC with a Mercury 225, 25" shaft, 90 gallons of fuel under deck, and I can cruise all day between 3200 and 4000 RPM's all day long depending on the load I'm carrying. Once or twice a month I go out into the Gulfstream and collect 110 gals. of salt water, so I can do a water change in my reef tank, and this is when the larger motor really preforms to its max. Good luck with whatever size motor you decide on, but I always believe, go with the biggest motor your boat can handle, you never now when you will need it.

[DonV]

"I will bring your beer of choice. Cheers!"

Really?? How many? I've got a 23'er you can ride in.

[BocaSeacraft]

I finally purchased the new motor and am bringing the boat in today to have it installed. Hope to be back on the water soon. Ended up getting a Suzuki DF90 for the same price I would have paid for a Tohatsu. Had to go 4 stroke. I will report back once I have some hours on the new set up.

[sidelock]

We're still waiting !

[BocaSeacraft]

Well, motor is installed and went for the sea trial this afternoon. I just want to say the guys at Drummond Outboard in Deerfield Beach did a heck of a nice job installing the motor. Joel and Zach are a great father and son team who really spend the time to get it right. First impressions of the motor are very favorable. I'm still in the break in period but the DF90 gets the boat up on plane with ease, even with 4 of us aboard (about 750#) and half a tank of fuel, all equipment, etc. It holds plane down to about 3200 RPM with the 14x16 Suzuki prop. At idle it is so quiet I can barely tell it's running. The wife and I are taking it out tomorrow for the day to put some hours on it and get ourselves familiarized with the new setup. I will report back once we get a chance to put it through its paces after break in.