Home | Classifieds | History | Technical | Links | Store | About Us | Email
Topics Topics Edit Profile Profile Help/Instructions Help Member List Register  
Search Last 1|3|7 Days Search Search Tree View Tree View  

Atomic 4 feasibility

Old Marine Engine » Boats with Early Inboards » Atomic 4 feasibility « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Mike Haworth
Visitor
Posted on Wednesday, November 29, 2006 - 04:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Hi Guys! I have a small 13' dual-cockpit aluminum runabout, originally an outboard, but I have come across an old atomic 4 with direct drive in pretty good shape, and am seriously considering converting to full inboard. There is plenty of room, and moving the weight distribution forward towards the center of the boat is really appealing, as the boat is driven from the rear cockpit on the left-hand side, and tends to be really stern-heavy with an outboard hanging off the transom.
My question is would a 30hp atomic 4 be a viable candidate for this conversion? I am not familiar with the performance of this particular engine, and am not sure if it would have the horsepower, torque, rpm's to plane a small boat like mine, or is it just good for moving sailboats around when theres no wind?! Any wisdom regarding this would be greatly appreciated!
Thanks.
Mike.
Top of pagePrevious messageNext messageBottom of page Link to this message

miro
Senior Member
Username: miro

Post Number: 249
Registered: 11-2001


Posted on Thursday, November 30, 2006 - 12:53 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I suspect that you'd never get it up to plane with that engine. There are performance curves in Weston Farmer's book ( From My Old Boat Shop) that shows the HP vs speed for various hull shapes. The increase in HP needed is spectacular once the terminal hull speed for a displacement hull is reached. And even if you did get it up on a plane, you'd probably be going flat out , full throttle, burning a whole lotta gasolne and making a whole lotta noise.
These engines were designed for slower moving boats, where the captain and passengers enjoyed the passing scene and engaged in thoughtful conversations about old engines.
Slower is better.

miro
Top of pagePrevious messageNext messageBottom of page Link to this message

bruce
Senior Member
Username: bruce

Post Number: 129
Registered: 07-2002
Posted on Thursday, November 30, 2006 - 09:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Mike, Are you describing a boat built by Feathercraft-dual cockpit-radical tumble home?? Try putting some sand bags toward the front when piloting alone-trim your outboard to bring the nose down. This sounds like a lot more fun as an outboard boat-nix the Atomic Four plan IMO.
Top of pagePrevious messageNext messageBottom of page Link to this message

Mike Haworth
Visitor
Posted on Thursday, November 30, 2006 - 04:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Thanks for the info! I'm not completely discouraged. I have been told that originally my Lone Star Admiral was powered by a 25hp Johnson. Although speed would be great, its possible that it was never more than a picnic cruiser. (I much enjoyed the mental image of cruising around discussing old engines) I have been (slowly) deciphering different websites relating to performance curves. Will keep you posted
Thanks again.
Mike

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Password:
E-mail:
Options: Automatically activate URLs in message
Action:

Administration Administration Log Out Log Out   Previous Page Previous Page Next Page Next Page

Home | Classifieds | History | Technical | Links | Store | About Us | Email
&copy 2005 OldMarineEngine.com, P.O. Box 188, Forest Dale, VT 05745-0188 • Phone: 802-247-4864 • All rights reserved.
   Marine Engine Seloc Repair Manual Lookup Tool

marine gas engine repair and restoration