Boat balance

nightvision

Petty Officer 1st Class
Joined
Mar 7, 2004
Messages
252
Hi all,<br />I'm in the process of rebuilding a 15 footer trihull fiberglass boat. I have a couple questions:<br /><br />a. Is there an ideal place to position flotation foam. I removed a block of flotation foam that's about 1.5 feet x 2 feet under the bow seat. Can I cut that up and move it to the very tip of the bow. If cut up, I can get the same amount if material in there. that way I have more storage space under the seats. I will also put more flotation foam in between the stringers.<br /><br />b. when balancing a boat. Do you want more weight in the bow or back of the boat? I was thinking of building a cooler area or live well in the bow.<br /><br />Thanks.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Boat balance

Nightvision<br />To start with is this a Inboard, Outboard, or I/O. In general you want the weight on the dock or in your truck. On the boat weight should be low in center of the boat from mid ship to the stern.<br />While weight up front may help in the small chop you want the bow to rise over the big swell.<br /><br />Floatation I feel should be out to the chimes and ballanced side to side. Since most of the weight is in the back you want a lot of floatation in the back. To me only flotation worth putting in is level flotation. So if the boat should fill with water it will float level. What is the point if all that is above the water is the bow. As long as ballanced then the more the better. I would leave the center open for a drain. If you add enough you can make your boat self bailing. Make sure you use only CLOSED CELL FOAM.
 

sloopy

Captain
Joined
Jul 12, 2002
Messages
3,000
Re: Boat balance

You want the boat to be level in the water. You do not want the bow pointing to the stars or have to put an airplane prop on your outboard because the LU is no were near the water. Although most of the time you can trim it out once on plane. Since you are rebuilding this boat, go out and find someone who has the same boat and take a picture of his boat in the water with no gear or people on it. Since you did not tell me what type of boat you have I really can not search for a picture of one or a web-page with facts.
 

JasonJ

Rear Admiral
Joined
Aug 20, 2001
Messages
4,163
Re: Boat balance

It doesn't sound like there is enough foam. Like Boatist said run your foam under the floor. My rig has foam under the entire floor except the center bilge. I have seven voids between the stringers (six stringers) and there is 16 cubic feet of foam under the floor, enough to keep the boat level and at the surface if swamped. 14-16 cubic feet of foam should be more than enough for your size boat.
 
D

DJ

Guest
Re: Boat balance

nightvision,<br /><br />Being that ypour boat is 15' and an I/O, I would suspect that she is already stern heavy, at least at rest.<br /><br />Bias the foam, toward the rear, yet fill as many voids as possible.<br /><br />I do not believe a cooler, in the bow, is going to cause you any weight distribution concerns.
 

ThomWV

Senior Chief Petty Officer
Joined
Dec 19, 2003
Messages
701
Re: Boat balance

Who said it was an I/O? I don't think it is. If it was there wouldn't be room to sit, let alone build a livewell or something up in the bow.<br /><br />I would think that the question here really isn't about weight anyway, its about filling up spaced on a small boat that might otherwise find good use. Hell, what does he care about the weight of a couple of cubic feet of foam? Its not as heavy as a 6-pack. Foam isn't the question at all. The real point is that if your boat is an I/O at 15 feet its got plenty of power no matter what engine you have - even the smallest 4-cylinder. So in that case extra weight of a live well or whatever isn't going to make any difference at all in the bow. On the other hand if its an outboard of modest power the weight in the front is going to make a great deal of difference, and shouldn't be there.<br /><br />Thom
 

sloopy

Captain
Joined
Jul 12, 2002
Messages
3,000
Re: Boat balance

a 15 foot I/O tri?!?!? I would pay to see this.
 

nightvision

Petty Officer 1st Class
Joined
Mar 7, 2004
Messages
252
Re: Boat balance

Hi all,<br />My boat has a 55 hp outboard motor. the reason for removing the foam is to make extra room for supplies and freeing up room midship and stern.<br />Thanks for the contribution.
 
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