saturated foam?

Akingjeeper

Cadet
Joined
May 23, 2007
Messages
10
Hi. I'm new to the site and would be greatful for any help. I read other postings about foam and what you have to do to get it out and replace it but my question is how do you know how saturated it is and when is it time replace it? I have a 20 ft Grady. The guy i bought it from told me it has the foam filled hull. (new to boating too) The bottom is rough so i was going to sand and redo the bottom. There are two spots where it looks like water is dripping through the cracks in the paint. Not a lot, but a drop every once in a while. The spots are not soft. I used the boat last season and it sat fine in the water. If the bottom was saturated, wouldn't you be able to tell when it was in the water?
I hope this makes sence and thanks again for any help.
 

Windykid

Lieutenant Junior Grade
Joined
Apr 17, 2007
Messages
1,177
Re: saturated foam?

You probably should find out the dry weight and add motor weight come up with the weight it is suposed to be. then go weigh it on a scale, if there is a major difference you are probably water logged.

Some seem like they are sitting well but you will notice it at WOT. Does boat plane off well? Or is it labored?
 

sdunt

Petty Officer 1st Class
Joined
Sep 11, 2005
Messages
389
Re: saturated foam?

If while it is sitting on the trailer there is water dripping from the hull, you have water logged foam. Take an ice pick to the floor and find out whre it is soft and rotted. Also check your transom down low around the drain plug.

You can not dry out foam and there is no degree at which wet foam is ok. If it is wet at all, it will lead to rotted stringers and floor, etc. People have tried all sorts of trick to 'dry out' the foam, heated garage, blowers, etc and once its wet, it has to be physically removed.

also you can weight your boat with a bathroom scale:

Here is the method I use to weigh boats on a trailer without hauling the boat to a commercial scale, which requires two trips for boat and trailer.

It's simple, accurate and will cause bystanders to marvel at your engineering whiz.

The boat stays on the trailer the entire time. Put the scale under the tongue near the end. You can even put a block on the scale to lift the tongue so you can see the dial. Record the weight. Now, slide the boat aft on the trailer 12" to 18". You must measure exactly how many inches you moved it, and record that. With the scale in the same location under the tongue, record the new scale reading. Finally, measure the distance in inches between the trailer axle (wheel centerline) and the point on the tongue where it touches the scale. You have then four measurements:

W1 = first (heavier) scale reading in lbs, W2 = second scale reading in lbs, X = the distance you shifted the boat in inches, C = distance between trailer axle and scale point in inches.

The formula is Boat Weight = C (W1-W2)/X

A couple of notes. The result, like any measurement, is sensitive to the accuracy of the input data. In this case, the most critical is the distance you slide the boat. One inch error out of 12 inches will really make a difference in the result. Slide the boat as far as you can and still have a readable load on the scales. Notice, too, that by subtracting the two scale readings, any constant error in the scale is canceled out.

Note to techies: The formula was derived by taking the sum of the moments around the trailer axle for each case and (since the sum of moments about a stationary object is zero) set the two equations equal to each other and solve for the trailer weight. Things that you don't know, like the trailer's weight and the location of the boat's center of gravity cancel out, leaving just the variables that you can measure, and the boat weight.

I also use another version of this formula for weighing a boat while it is under construction so I don't get a bad surprise when it's finished. You can use two bridged scales and/or a trailer extension to increase the range of weights you can measure. I usually shoot for measurements of about 30-40lbs
for a low end and 250lbs or so for the high end.

The easiest way for me to accomplish this was take the bathroom scale and tape measure to the ramp. When I pulled the CS out I allowed it to stay aft on the trailer held in place by the bow wench line. Once on the parking lot I cut the trailer loose from the truck and weighed the tongue. I then measured the distance from the transom to the end of one of the bunks. Now I pulled it forward with the wench. I measured the difference in posistion and re-weighed the tongue.
 

TD_Maker

Chief Petty Officer
Joined
Aug 31, 2005
Messages
564
Re: saturated foam?

Aking,
I had a mid eighties Robalo which had water soaked foam. The boat was REALLY heavy due to all the water soaked foam. I was able to remove a built in tackle box to gain access to some foam. You could literally push your finger into the foam and it would gush water. I did some research, and this was a common problem with boats in this era, particularly with Grady and Robalo.

Unfortunately, there is not an easy fix. I had a friend who had a barn which was no longer used. He let me park my boat in the barn out of the weather. I drilled dozens of holes in the bottom of the hull to just let her drip dry out. it took more than a year to get her bone dry. I filled in the holes with glass filler, painted the bottom with a good bottom paint, and she was good to go. In fact, I sold the boat a few years ago; however, I did see her in the inlet last week.

Just make sure you fill in all the holes in the flooring topside, and dont forget to pull your plug if it rains!
 

Akingjeeper

Cadet
Joined
May 23, 2007
Messages
10
Re: saturated foam?

Thanks for all the replies.

I weighed the boat. Unfortunatly, i could not take it off the trailer at the time and i have no idea how much the trailer and motor weigh. The total weight is 3100lbs. this includes the boat, a 74 evinrude 115 outboard motor and trailer.the trailer is a Sea Lion trailer with 4x3 rails and swivel style rollers. The boat is an older boat and has very high sides, unlike newer boats. To give you an idea of its size and shape it has two pedistol chairs at the front then about 2ft behind them it has the back to back seats, one on each side. anyone know if this seems close to the weight it should be or does it sound heavy? I couldn't find the dry weights of anything.
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: saturated foam?

Your motor weighs in the neighborhood of just under 300 lbs.
 
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