How to increase my scoop volume

[Tony Matusadona]

I have a 35 foot sailing Cat. The scoops are well sized but lack height which means continuous water movement over them and regular cleaning. I want to add 100mm to the level. Does any one have a plan/guidance/recommendation. With thanks

[Sand crab]

Usually lengthening the stern will result in more buoyancy which will raise the height. Lots of threads and vids on this. See Parlay Revival on YT.
Which cat?

[GordMay]

Greetings and welcome aboard the CF, Tony.

[catsketcher]

Gday Tony

If I was to do the work I would need to know what the current materials are, a few pics of the current set up and its limitations, whether you are going to do the work yourself and what materials you are happy with.

Get back to us with some pics and some more info.

cheers

Phil

[carlosproa]

Originally Posted by Tony Matusadona

I have a 35 foot sailing Cat. The scoops are well sized but lack height which means continuous water movement over them and regular cleaning. I want to add 100mm to the level. Does any one have a plan/guidance/recommendation. With thanks

I have seen in the past a similar length cat done with a tortured melamine 4x8 with straps and wood stringers. Is somewhere in the web. They used epoxy, fiberglass cloth, foam.
Looked very doable, the trick was how back in the old fiberglass to start the skarfing

[thinwater]

Originally Posted by Tony Matusadona

I have a 35 foot sailing Cat. The scoops are well sized but lack height which means continuous water movement over them and regular cleaning. I want to add 100mm to the level. Does any one have a plan/guidance/recommendation. With thanks

Photos, please. Hard to make useful comments without them (I have extended the transoms on my cat).


Water washing over the steps should not result in cleaning, any more than water splashing on the side of the hull. What increases cleaning is POOR DRAINAGE. I'm guessing they are sitting level and hold water. All you probably need to do is add a thin wedge to give more slope. I'm assuming you are a good hand with glass, other wise, this is a pro job.

• Buy a sheet of 1/4-inch structural fiberglass.
• Bevel the trailing edge to ~ 1/8".
• Add three stringers with a 0-1.5" cut, about 3 inches shorter than the 3-foot extension. These could be wide foam or built up from 1/4-inch GRP. Epoxy putty these down, with the sheet on top.
• Tape and far as needed. Many details.

Many variations. The height of the wedge depends on the existing slope. But all you need is some slope. Mine are about 20:1 slope.

The other source of dirt is draingage off the deck. Making them higher won't help with that either. You need slope so that they are self-cleaning.


Making them higher will make boarding more difficult, from the water, kayak, or tender. . It will.