Adding keel weight to small houseboat

Could also add bilge keels…not sure about the design, but probably something above the planing area of the hull that when the hull sinks or ballast is added also dampens roll.

 

Sorry, I got tied up with some things and didn't get a chance to do some figuring since most of my notes are across town in the warehouse. There isn't a whole lot of info on this hull as it was only made for a short period. From what I can tell looking at some old photos and the few manufaturer pictures I could find the designed draft was between 7 to 9 inches depending on load and balancing. This was with the hull weight at 975lbs. Rough calcs put the displacement at 7" around 2400lbs conservatively with a PPI of 350lbs+/-.

I think your note about weight central vs saddled is interesting and not something I've really considered. I can't test the theory with the hull as it's on supports, and won't be moved until the floor is foamed in and secured. Ballast tanks are not an option on a hull this small with limited room, and would add more complication then I'm willing to get into. I've got some inquires out to a few guys who have done terminal trawler conversions and I'll let you know if they respond with anything decent. Either way I need to decide soon as the foam has arrived.

 

Everything will be built very lightly. I'm struggling mentally with that since I like to over build, lol. The base hull when done will be much lighter then originally built. They used DF 3/4" for the stringers, transom and deck, and the console was reduculously heavy. Once stripped the actual thin fiberglass shell weighed very little. That is part of the reason why I am considering adding weight back.

 

No planing. I'm planning on a smaller outboard and displacement speeds of around 6.5mph. Bilge keels are possible and wouldn't to hard.

 

What did you ‘strip’ out? A thin glass hull may have needed support.

You should trust me on not adding keel weights; it is the wrong way to go. A trawler is built with a deeper vee, in general, and ballast is sometimes added to get to dwl. Your hull shape will not benefit from central weights along the keel. Whoever told you this is broad brushing the concept across all hulls.

 

It is a very thin glass hull. I bought it because for it's size I thought it would be a decently beefy hull given the weight. All the info I could find on them and the similar kenners were that they were tanks. Come to find out differently. The hull had a good twist in it too. After I replaced the transom, the floors and stringers were removed. I built a support structure under the hull to support and level it while I rebuild. The foam and floors are the last part of that step. I feel the foam is definitely needed to support the hull, like a Whaler.

I don't disagree with your assessment, I just didn't really consider it. In my world, planing power boats, it's all about reducing weight, never adding it, for shallow draft. I think I'll skip the weight all together.