Cool Ballast Idea

[DAFF]

Here are my numbers....
20' long 2.5' wide average depth of 6".
25 cubic feet per side =50
375 us gallons *8lb/gal

3000 lb......

[DAFF]

Go ahead and do it to the Sunsport. Its just fibreglass, worse case scenario you have to repair the transom.

[DAFF]

Drilling three 3" holes in the transom with gate valves would achieve the same results other than filling on the go.

[wiatowski]

Math is good, as for doing to the Sunsport... hahaha.... maybe. I like the point of filling on the go and being able to take off without the weight. Would maybe reduce the volume for around 2000 lbs of weight.

[CornRickey]

The critical part is the vents

[Salty87]

Here are my numbers....
20' long 2.5' wide average depth of 6".
25 cubic feet per side =50
375 us gallons *8lb/gal

3000 lb......

it seems fairly straight forward until you open the floor up and see the space you have to work with. it 'could' be done but you'd have to be a world class fiberglasser & decent engineer. the smaller side stringers get in the way and restrict the space unless you flood all 4 compartments instead of just the main 2. then there are cross braces every 3-4 feet. plus you need to get a serious seal where the floor contacts the stringer tops. on top of those issues your fiberglassing needs to survive being submerged. you really want to use composite materials for this.

redesigning the stringer layout would be a good idea to maximize space and also increase the fill & empty speeds. it's an overwhelming project when most people are just in a rush to get their boat back together and on the water. i'd love to see someone do it though.

[wiatowski]

it seems fairly straight forward until you open the floor up and see the space you have to work with. it 'could' be done but you'd have to be a world class fiberglasser & decent engineer. the smaller side stringers get in the way and restrict the space unless you flood all 4 compartments instead of just the main 2. then there are cross braces every 3-4 feet. plus you need to get a serious seal where the floor contacts the stringer tops. on top of those issues your fiberglassing needs to survive being submerged. you really want to use composite materials for this.

redesigning the stringer layout would be a good idea to maximize space and also increase the fill & empty speeds. it's an overwhelming project when most people are just in a rush to get their boat back together and on the water. i'd love to see someone do it though.

Agreed flooding all 4 compartments is in order. How about coating with Line-x over the glassed stringers. To seal the stringers isn't really that much of a problem, as stated above as long as it's vented properly there really shouldn't be that much pressure.

[CornRickey]

Sounds like a aircraft fuel tank. I wonder what they use to seal everything.

[Jetlink]

Sounds like a aircraft fuel tank. I wonder what they use to seal everything.

RTV usually, but those are not placed under much pressure.

[DAFF]

Glue in a pond liner which encases everything. The seal point could be where the centre stringer meets the floor. Venting and drilling holes would be EZ. To me anyone who is in the market for a cap off resto would be crazy not to attempt it.