Pontoon cabin boat re-visted

As I stated in an earlier post I'm building a week ender using 24 ft pontoons.The cabin frame is made from 2" square alum; it measures 8x12 with an 8 ft over hang in front and 2 ft in the rear.I sold my 20 footer / trailer and kept the 90 hp Suzuki 4 stroke and bought the trailer in the pic. Next step is re-decking the toons with marine plywood.Will kept updated for those that are interested.

 

Do yourself a big favor and put some crown in tat cabin roof or you'll retain water when it rains, which isn't good. 4" across 8' is a good place to start for a slight crown.

 

Next step is re-decking the toons with marine plywood.

WHY?

Almost all house exterior ply uses waterproof glue , save some cash.

The best construction would be really thin ply with stringers to curt down on the flexing at the lowest weight.

No matter what service , less weight is a better boat.

 

I am agree with him_t][t

 

I disagree Fred. Marine plywood is twice as strong at usually 40% to 50% of the weight of construction grades. This means you can employ 3/8" soles for the strength of 3/4" CDX and still have the same strength, which is a huge difference. If the stringer spacing (what holds up the sole/decking) is fairly tight you can use 3/8" or 1/2". I suspect the strength issue will be much needed on the cantilevered sections he's talking about, so marine plywood is a logical choice.

 

This boat is being built using an existing proto-type,any necessary improvements are being addressed.The roof and siding is SIP[two sheets of alum. with foam center] which is relatively light and has a good R rating.Water retention wasn't a problem because the boat always has a slight pitch.Yes,there is a difference between marine and exterior plywood,no voids and and extra layer of veneer.I'm going with 5/8,which is what it came with,weight savings is a big factor.Also,the alum. framed doors and windows will have either vinyl or thin plexiglass panes.Forgot to mention that the cabin frame is upside down on the trailer with the front pointing towards the rear of the trailer.

 

This is the proto type,many improvements have been made since this pic and will be incorporated in my boat,justs gives the idea of what I'm aiming for here.

 

looks like a fun craft, houseboat?

 

Yes,we used the above boat mainly for speck fishing overnight.It has two dry storage boxes that double as bunks and two bunks above the storage boxes that fold onto the walls when not in use.Ice chest and propan stove,everything is light and portable.Porta pot is outside in back but covered and I even plan for one of those propane fueled water heaters on the other side.

 

Up Date on Speck-tacular

I managed to get some work done over the last week,got the cabin frame off the trailer and got the boat off the blocks and back on the trailer,it's a lot like work when you do it by yourself.I removed the old decking and getting it ready for a new 3/4 marine plywood deck,of course 80% of the screws required cutting off the head and the remaining piece will have to be removed before decking.My brother in law came over and we moved the transom back two feet.We unbolted it from the pontoons,leaving it attached to the three cross braces and slid it back to the existing holes.This was done to give me some much needed room on the rear deck,I've also read that there's other advantages.The transom still has the three original braces and I'm adding a piece of Z bar off each pontoon to the transom but leaving it open for motor tilt,will post pics of that mod when it's done.