1988 Mark V HD

[klink916]

Recently bought this '88 Mark V Heavy Duty and have a few questions. Its in relatively good shape, holds air and all the seams look to be solid. It has no floor in it and also appears to not have an inflatable keel.

First off can I use my later model MK1 floor pieces and fab a few more to take up the extra floor space? Second is the performance going to suffer due to being essentially a flat bottom? Have a 50 HP 2 stroke to mount on it also.

Thanks in advance for any input

[office888]

Originally Posted by klink916

Recently bought this '88 Mark V Heavy Duty and have a few questions. Its in relatively good shape, holds air and all the seams look to be solid. It has no floor in it and also appears to not have an inflatable keel.

First off can I use my later model MK1 floor pieces and fab a few more to take up the extra floor space? Second is the performance going to suffer due to being essentially a flat bottom? Have a 50 HP 2 stroke to mount on it also.

Thanks in advance for any input

The boat will not work properly without a keel.

The MK V has a very wide beam, I do not think your old floorboards will work.

You will need to fabricate a floor that is about 25mm longer than the measured distance to properly stretch the boat.

[klink916]

So did these early model use the floor pieces to create a keel? My later model had an inflatable piece running down the center that the floor essentially pushed down to make a keel.

[spartacus]

Originally Posted by klink916

So did these early model use the floor pieces to create a keel? My later model had an inflatable piece running down the center that the floor essentially pushed down to make a keel.

It would have had an inflatable keel which has subsequently been removed. They can leak at the transom end where it's thermobonded, and can be repaired. Zodiac sell them as replacement units.

[Starovich]

I believe these had a "futura" hull.

[office888]

Originally Posted by klink916

So did these early model use the floor pieces to create a keel? My later model had an inflatable piece running down the center that the floor essentially pushed down to make a keel.

No, it had a keel, it was just probably removed by the Military before the unit was decommissioned.

You can fabricate a keel out of wood. Use the Bombard Commando for inspiration.

[office888]

Originally Posted by office888

No, it had a keel, it was just probably removed by the Military before the unit was decommissioned.

You can fabricate a keel out of wood. Use the Bombard Commando for inspiration.

In order to properly custom make a floorboard set for your boat, you will need to take some exact measurements of your particular boat.

• Inflate the boat to 240 mb and leave to settle for 4 hr
• Before measuring, check pressure and top off as ncessary
• Measure between the rear of the fixed floorboard (the thrustboard in the bow) and the transom where the stern floorboard section rests against it

The floorboard should be made to be at LEAST 55mm oversized from the total length, optimum is 65mm oversize, 75mm maximum.

The idea is the extra length stretches the boat out and locks the floorboards in place.

You will need some stringers that lock the floor in place and lock them from flexing up and down. They are triangle shaped blocks that fit over the floorboard "joints", and fit snug in between the joint for the tube / bottom of the boat.