what size of boat should I get?

bagpipeswest

Cadet
Joined
Feb 5, 2009
Messages
14
I've been here before, years ago it's round two time to get back into boating. I want to fish in the big pond Pacific Ocean (Naniamo) BC Cod, salmon

I've just bought a 1980 70hp Johnson that needs some work, I sure I will be back here asking questions about it. But what I want to do is run two 1980 70hp Johnson's on my boat.

What should be the min length should it look at. any particular type of boat. I was thinking fiber glass 19' to 21' any year or up to 1980ish.

Please ,, i'm at a loss on this one, need a bit of help. I currently drive a jet drive 42' with two CAT diesels @ 500hp each. Lovely boat. not mine . but it's my job

Cheers Brent
 

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
I have been on the Pacific in a 20' cuddy and I can say it was not the best day. My grandpa had a 25' and we went out all the time. Many good memories on that boat. But it was a boat for big water where the 20 was a bayliner or something and was more for lakes.
In my opinion, any good brand center console (boston whaler and such) should do you well. Also I think using two engines is a great idea. I would suggest each being big enough to get you back to port by itself.
 

ssobol

Chief Petty Officer
Joined
Sep 3, 2010
Messages
503
Two 80's 70hp motors is going to limit you to something about 20-22 feet tops. It will depend a lot on the hull shape. A 20' deep V (for big water) is going to have a hard time planing on 140hp. You can get a nice displacement hull that will work with 140hp, but it won't be very fast.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
When I was younger my grandpa had a 18 or 19' Reinell that we used in the Straits for probably 10 years. It had a Volvo 2.5l I/O in it and did fine for fishing.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Agree on 140 hp which isn't 140 hp on an engine of that year model. Back then engines were "brake" hp rated which means powerhead with nothing attached. So you have to take off 10-15% of that for engine ratings for pre mid 80's produced engines. Plus given wear and tear they probably wouldn't dyno out to 70 brake anyway. In big water you use up a lot of hp fighting waves if caught in bad weather....normal weather down here....seems wind always blows and worse in the afternoons when you are trying to get back to the dock. I think I know what and where you talking about in making your living and you probably have experienced a lot of what I am talking about with heavy water.

As stated above boat (hull shape) and load make a big difference in what you can get out of what.

Might look around at some dealer's and marinas and see what has what hanging off the transom and remember the powerhead vs today's prop rating difference.

Outside of that I always found that my boat(s) were always too big out of the water and too small in.

HTH,
Mark
 
Last edited:

bagpipeswest

Cadet
Joined
Feb 5, 2009
Messages
14
Great info What about the sheer weight of the two engines. 500 lbs ish. would you hang them off 19' ft V hull like a Double eagle. I don't want to over load back of the boat to the point of it being unsafe. Just throwing the idea out there.
 

ssobol

Chief Petty Officer
Joined
Sep 3, 2010
Messages
503
Most of the time the boat is sized for the intended use and then the motors are sized to the boat. Working back from the motor size is not the best way to do it.
 

bagpipeswest

Cadet
Joined
Feb 5, 2009
Messages
14
your right... not the best way. But Im in no rush. I should have my first Johnson restored by early spring. I havent found the second one yet.. When the right boat comes along.I'll be ready I need to know what the right boat is.

You guys have been great. Keep you ideas coming. To add,,, I really tend to stay away from ugly weather. 10 knot winds are the limit. will will stay 2 mile from shore. I do want to take it out on a lake as well.

BM
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
SWAG: (The S is for scientific.....grin) I'd say if you were into an 18' or up boat with a wide enough transom cutout to fit two engines you are good to go. A boat of that size would carry a 150 hp and that's around 400# with the thrust twisting force and weight in the center, in one spot not, distributed like yours and closer to the sides of the boat.

Mark
 

roffey

Commander
Joined
Nov 22, 2012
Messages
2,187
this may be a dumb question but, with two motors one has to be counter rotating, right?
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Not necessarily but it does help to stabilize steering and boat tilting as a result of the torque. I don't think you have to worry about the engine. Just get a counter rotating prop with everything the same as the rt hand prop except the blade direction is reversed.

Mark
 

crb478

Lieutenant Junior Grade
Joined
Dec 6, 2006
Messages
1,036
You will need a counter rotating prop and gear case. I am sure if your not in a hurry you can find the parts to convert one of the gear cases
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
You will need a counter rotating prop and gear case. I am sure if your not in a hurry you can find the parts to convert one of the gear cases

I just started to reply to your input and just mentally went through the process. If you didn't have the drive changed to ccw with the ccw turning prop it would be like the CW prop (port side) would be in reverse with the CCW prop blade geometry. Sorry for my stupidity and apologize for any disinformation.

Good Luck,
Mark
 
Last edited:

bagpipeswest

Cadet
Joined
Feb 5, 2009
Messages
14
ok Now my brain really hurts. I have look at pod conversions inboard to outboard, length of boat, how much will it sink in the water, will it come up on plane. what does a chevy 350 weight verses a twin 70hp Johnson ..

I think what would the best for me is find an 18' that had an out board on it. and start off with one 70hp. Then stick the other one at a later date. If the boat is rated for a 140hp? I should be fine. Right?

Question Can I re-enforce a transom from the inside of the boat only. or will I have to do it from the outside ?
 

undone

Petty Officer 2nd Class
Joined
Jul 26, 2014
Messages
147
I think you may need to redirect you thought process.

Twin engines of this size on a small boat doesn't make much sense, a typical West Coast 20' boat probably wouldn't get on plane with one motor, so your speed is limited. It will also use more fuel, be slower and require twice the maintenance of one larger motor. The normal set up is a single large motor and a small motor for trolling, something in the 9.9 to 15hp range works well. This small motor will also get you back to the dock when needed.

Any boat of that vintage will need a complete rebuild, this means transom, floor and stringers. And while some do have the space for two motors, many won't, so you will either be limited in options by design, or you can modify the transom to run twins. This may mean widening the mounting area and raising the transom height, twins need to be mounted higher on most hulls. But if your desire is to own a boat with twins and that's the goal, then go for it.
 
Last edited:

BF

Lieutenant
Joined
Apr 8, 2003
Messages
1,489
Since you seem to be looking at this long term a project... how about watching for a Starcraft Islander with a blown OMC drive, and converting it to dual outboards? I don't know anything about coastal boats, but it seems (?) like it be a good hull to work from... and aluminum might be the way to go. I think those boats did OK with a 4cyl I/O, which wouldn't be much different than twin 70's...
 

undone

Petty Officer 2nd Class
Joined
Jul 26, 2014
Messages
147
It makes little difference what the boat is, but it probably is a Fiberform, they say it's solid, it's not, any boat of this age will have rotting wood that needs to be replaced, so it will be a total rebuild. The only things of value are the kicker motor and the trailer, the boat and main motor have no value, so $2000.00 is more than double the actual value.

The brand and original build quality means little when boats are this old, you will be rebuilding everything from the hull up, so the quality will be up to you this time around. All you need to do is find the right type, style and layout as a starting point for your new project.



PS. "the recently painted" comment actually reduces the value even more, it's one more thing you will need to spend a great deal of time trying to fix.
 
Last edited:

bagpipeswest

Cadet
Joined
Feb 5, 2009
Messages
14
Thanks for you input. I value it a great deal. I thought it was a too high of a price. way too high. New paint can hide old problems. I'd rather buy a car with original paint. you can get a better idea of the rust.

thanks again.
 
Top