Boat Remodeling Project Part 1

[gunflint]

I'm a few weeks away from starting my winter boat remodeling project. I need to submit a budget. I've got most items figured out. What I don't know is what kind of wood to use for decking and what type and how thick of floatation material goes underneath the deck.

This is a 16 foot boat with a rear bench. The middle bench has already been removed (previous owner) and the front bench is part of the casting platform. My plan is to remove the rear and front bench's along with the casting platform. Doing so will elimnate the boats floats. What type of wood is recommended? Where can I get the floatation material? How expensive is a couple of 4 x 8 sheets of this stuff? Thanks

[Valv]

Gunflint beware if removing the benches you will also remove any support for the sides, you will have to compensate with the decks to hold sides in place.

Steve Bakken is the expert on this.....

[Guest]

Valv is correct.. your on a road to disaster if your going to remove the rest of the benches.

You can get away with pulling the center bench without losing much for structural support. The rear bench, and the front 2 have to stay there unless proper structural support is put in place... or something that connects to both sides(in a solid way), or connects to the sides and the floor.

Making a flat floor design is not going to happen without some serious support, or a pretty large hood on the front of the boat.

[gunflint]

I'm not too concerned with supporting the gunnels. Whoever did the first remodling job left about 10 inches of bench and supported the gunnels to the bench sections with braces. I plan to do the same with the rear bench and connect the rear and center bench with a rod storage compartment. So the integrity of the gunnels should be fine. The boat does have a big bow hood.

I will be measuring widths before I start anything and will make sure the finished product is identical.

I've decided to leave the front bench in tact as it is already part of the casting deck. I will put a livewell in front of it.

I still need to know how thick of floatation material will be needed to keep the boat afloat. Thanks.

[Valv]

Gunflint, the boat doesn't float because of flotation material, it will do it regerdless of it.

Flotation foam is only to keep it afloat un case of capsize, it will slow down the sinking.

You can have no foam and still have boat at same draft.

[gunflint]

I should clarify this a little. I understand that the foam (for lack of a better term) is to slow down or stop the boat from sinking caused by either capsizing or puncturing. This boat is used as a guide boat and carries paying clients. I haven't checked into the regulations but I would assume that by making alterations, including the ones that have already been done, every step should be taking to assure the safety of said clients. So I guess my concern is more of a liability issue than an engineering issue. To be honest If I didn't use this boat for guiding and it was stricktly for personal use I would just slap some foam where I could and call it done.

What I'm thinking is that the only flaotation material in the boat now is what's in the back bench and the front bench. I'll know for sure about the front bench in a few weeks. I wouldn't be surprised to find that there's nothing under the current deck. I was thinking of adding an inch or two of foam under the new decking but maybe I won't have to.

[Valv]

You might want to consider another issue if you are renting this boat out. Is your liability insurance going to cover an accident on a modified boat ?

I would be sure thet your current policy will cover any damage to other (renters) if using this boat and have an accident. You don't want to pay out of your own pockets if something happens....you know what I mean.

I am not trying to discourage you Gunflint, not at all, just laying all the possibilities on the table, before you invest money and time on this project.

I think if you don't find any foam under your deck, and you want to add some it won't be a problem at all, in fact I am sure it will be beneficial, just be sure to get some "closed cell" type, so it won't absorb water and get heavy.

[wastewaterguru]

The calcs for displacement are pretty easy. Take the boat weight times pounds of water per pound of aluminum (62.4/168.5) will give you pounds of water displacement. Then divide by 8.34 pounds per gallon to get gallons of displacement and divide again by 7.48 to get cubic feet of displacement.

600 pound boat * (62.4/168.5) / 8.34 / 7.48 = 3.56 cubic feet of floatation space. I don't know the specifics of the closed cell foams......but only a portion of the volume of the foam is displacement (between 80 and 95% depending on type of foam). And then throw in a safety factor of 20 to 30%.....

3.56 cubic feet * (1.2 for 80% foam) * 1.3 (30% safety) = 5.55 cubic feet.

You get the idea......it isn't that complicated.

[Chris Haley]

Gunflint

Unfortunately I think it may already be too late. Any modification like what has already been done will void your guide insurance. At least it would mine. (Old Guide Insurance)

[Steve Bakken]

I knew there was a reason I shouldn't have dropped out of math..... anyway, it's always better to have too much foam than not enough. Nobody ever got sued for their boat floating too high in the water after capsizing. When we do any type of modification, especially when adding weight such as plywood, carpet, etc., we always replace each square foot of foam that may come out of the boat such as with the removal of the bench seats, and then add extra in the unused spaces such as under the floor, perhaps under the gunwhales, etc.

[gunflint]

When I first decided to undertake this project, I assumed that the currenet layout,including decking and pedistal seats were an aftermarket addition, now I'm not so sure.

I spent over an hour googleing the manufacture and finally found out a minimal history. It will be another week or two before I get the old carpet and deck up but it seems likely at this point that the layout is from the factory.