Cockpit floorboards for runabout

[jeff pierce]

I am at a stage where I need to make a decision would like to hear opinions from the forum. I think this is mostly a matter of personal preference, which usually makes for an interesting discussion. http://media5.hypernet.com/~dick/ubb/smile.gif

For those who don't recall, I am building "Malahini" by Glen-L. It is a 16' plywood hull "outboard runabout" with a single open cockpit. She will be finished bright, both hull and decks, as is typical of pre-1960 mahogany runabouts.

I'm ready to put flooring in the cockpit and I'm not sure what I want to use. The plans call for 3/8" ply in three sections. (A center section and two outboard sections that fit around the hull frames). With the floor framing in the plans, this seems underdesigned. The center section has large unsupported areas (3' x 3') per plan. I could either add more framing or go with thicker ply. Either way, if I go with ply, I would probably glass (for durability), paint and add some type of non-skid.

However, I am open to other possibilities. I have considered making removable flooring sections from solid planking tied together on the underside by cross braces. Maybe I could space the planks apart a little to improve ventilation in the bilge area. I do want to be careful about adding too much weight.

What do you think?

[John R Smith]

Well Jeff

off the top of my head, 3/8 ply sounds too thin, especially with large unsupported areas. I think we have 1/2 ply in our cockpit, and it is very heavily and closely framed underneath. There is nothing worse than than a flexing, insubstantial floor.

Our marine ply is just painted (Danboline grey) and there are now a couple of corners where rot has got in and the wood is soft. I suppose epoxy sheathing would have prevented this.

If I was starting again from scratch, I think I might be tempted to do something with teak or iroko and not paint at all . . .

Having said that, ply is so quick and easy http://media5.hypernet.com/~dick/ubb/smile.gif

John

[Wayne Jeffers]

Jeff,

I like your second option. You can make the cross-bracing thick enough to rest on the hull underneath for addtional support, say every 12", between the frames, in which case 3/8" thick wood planks would be adequate. Not too heavy, either.

Wayne

[Salt Mullet]

You can notch your frames and install longitude battens on top of floor timbers to support the 3/8 plywood. Remember at some point , you will need to remove and clean under the deck boards. They will gain weight with age like all of us.

Sometimes if they get too heavy, you will have a tendency to ding areas removing them.

I am not sure of the layout you have, but you can also split you deck down the middle with a solid wood, 1x6 notched into the frames and make deck boards on each side to lift up. Keep in mind you will need to rabbit the sides of the solid board the width of the plywood to allow the plywood to lay on it for support.

[This message has been edited by Salt Mullet (edited 01-29-2002).]

[whb]

I remember a roll up beach deck I saw once.

The person had made it out of radius deck wood. Each piece was drilled across the width of the board top and bottom a cord was passed through and knotted between each. it was very nice underfoot. It would allow you to roll up your deck to access underneath and you could use whatever wood you wanted and put a radius edge on both sides.

Howard

[jeff pierce]

Originally posted by JohnRSmith:
If I was starting again from scratch, I think I might be tempted to do something with teak or iroko and not paint at all . . .


I just priced out teak...and its definitely out of the question.

My local lumber supplier has ipe, a tropical hardwood. The stuff nearly hard as a rock and very strong. Its marketed as "Pau Lope" and generally sold for decking (as in the structure attached to the back of your house, not boat decks). Like teak, it is supposed to be very rot resistant and requires no preservative. Unlike teak, I can get it for $2.94 a board foot. Any reason this would be unsuitable? I do realize that it is very dense and I'd have to watch the weight I'm adding.

[imported_Ola Sylwan]

Jeff,
Ipe has a density of 64 lbs/cubic foot which is more than water.
The floorboards will sink if you drop them overboard but the weight gain compared to plywood is not very large.
I would go with Ipe on looks and durability.
Find more at: http://www.fpl.fs.fed.us/documnts/FPLGTR/fplgtr113/fplgtr113.htm chapter 1.
Good luck, Ola.

[imported_Ola Sylwan]

More.
http://www.iswonline.com/wwp/wom/ipe.shtml

[WWheeler]

I remember the Peterborough runabouts used slatted floorboards that ran the length of the boat. They were easy to pull up for bailing/cleaning, but did the job to protect you from stepping into bilge slop.

The slats were connected by a battens/cross pieces, and they were held down just by friction against the ribs.

[bainbridgeisland]

I used 3/4" thick western red cedar on my motorboat. Supports are 15" between centers. Slats are 3" wide with 3/16" spaces between them. Finished with 6 coats of oil, they have stood up well.

The inside of my boat is painted, so the oiled cedar and a few varnished trim pieces really dress it up.

I chose cedar because it is durable and light weight. It is not terribly strong though. 15" spacing on the supports seems about right. It is nice and stiff but still light weight.

In hindsight, painted plywood would have been faster to build and easier to clean. I do like the cedar though. By the way, I agree, 3/8" plywood on 36" stiffener spacing is not correct. 13" spacing is about right for 1/2" plywood. 10" spacing is needed for 3/8" plywood.