Big motor, little boat.

[culpski11]

I have a 1995 Seaswirl 185E; the original owner upgraded the motor option from the 4.3liter to larger heavier 5.0 liter. I was wondering if there is anything that can be done to add stern buoyancy without compromising performance and handling.

 

[skibrain]

Re: Big motor, little boat.

Stern buoyancy? As in, if the boat were swamped and full of water, the stern would float higher? or when under way the stern is too low in the water and you'd like to remedy that?

 

[GA_Boater]

Re: Big motor, little boat.

The weight difference between the 4.3 and 5.0 is about 150 lbs. That should not cause much change to the performance of the boat, except power-wise. It's only roughly one passenger. Maybe the boat has some other problems (soggy foam maybe). A little more info night help.

And welcome to iboats. You posted in the Prop Questions and Topics forum. Props don't help "bouyancy". You might get better answers by posting in the Boat Topics and Questions (not engine topics). The folks here bend over backwards to help and some monitor some sections closer than others. Enjoy your stay and have fun!

 

[culpski11]

Re: Big motor, little boat.

Thank you, I will re-post. How would I check for soggy foam.

 

[culpski11]

Re: Big motor, little boat.

Sorry, while stopped(in the water) the rear of the boat sits extremely low in the water. the Seaswirl logo is almost completely under water.

 

[craze1cars]

Re: Big motor, little boat.

Your only answer to correcting this is to lighten the load at the rear of the boat. Adding buoyancy product inside the boat will do absolutely nothing...

Is this really a problem? Why does it bother you that it sits low when parked? How does it plane out and handle at normal speeds?

A few semi-practical things that can be done would be to pull the battery(s) out of the engine compartment and reinstall them as far forward in the boat as possible...maybe under the dash or up in the bow? This involves some rewiring and very heavy cables (0 gauge or 2/0 probably) to run the extra distance due to voltage drop. Also make sure absolutely NOTHING heavy is ever stored in the engine compartment. No coolers, no anchors, no skis, spare props, toolboxes, etc....NOTHING but lifevests in the back. All heavy items must get stowed as far forward as possible.

Small 18 and 19 ft boats with big V8's will squat in the back when they're stopped. Fact of life...not even sure your hull was ever designed to handle a motor of that size....

 

[Howard Sterndrive]

Re: Big motor, little boat.

How would I check for soggy foam.

use a hole saw and cut holes in some inconspicuous places (under seat bases etc)

 

[57Cadilac]

Re: Big motor, little boat.

You could take off about 70lbs on the engine by going to aluminum heads and probably another 10 by switching to an aluminum intake manifold (if not already done). Aluminum water pumps are fairly cheap and will shave some weight. Check to see if there is any water logged wood and consider switching to 1 good battery instead of 2 mediocre batteries if that's an option (that could drop another 35-50lbs).

 

[stackz]

Re: Big motor, little boat.

You could take off about 70lbs on the engine by going to aluminum heads and probably another 10 by switching to an aluminum intake manifold (if not already done). Aluminum water pumps are fairly cheap and will shave some weight.

and it'll add more power

if its non-vortec, look into some of the 90's aluminum LT-1 heads from camaros/corvettes. they are getting cheaper and cheaper.