Displacement VS single hull

[Fanie]

Hi Guys,

Something has been nagging me for quite a while.

The power boat I have currently is a 5m500 semi cathedral hull, 2m wide. Draft is around 150mm and deck clearance is around 500mm. The 115 does up to about 70 to 75km/hr flat out. Very stable to walk on, in general not a bad rig for venturing onto fresh water.

Only thing that I find very irritating is that if the wind picks up on some of our dams, you have to abandon fishing and 'retire to the lounge' so to speak. Being a single hull there can be quite a bit of roll and the risk of a wave splashing in becomes a risk. The boat won't sink, it has enough flotation for that, but it would be a very unpleasant experience as you can imagine.

Our boats have high decks where you can walk on and fish from, similar to the bass boats. It just works better to stand on the boat instead of in it, especially since we lure fish and cast almost all the time.

Now since I got involved with you hooligans, I got a liking in the sailing catamaran hulls that are wide apart and offers the space and stability.

So here's what I was thinking -

Hulls similar to a sailing catamaran but shaped so they can plane. The two hulls fit on a trailer side by side and when you launch the hulls expand sideways so a gap is between them, the gap between the hulls has a trampoline one can walk on.

This would result in a wider boat offering more stability, and more deck space to walk on. The two hulls should also be lighter in weight which should make trailering easier. If one make the hulls longer it would add to stability and still be within the weight of a single hull.

Anything one would gain from a setup like this instead of the single hull ?

Any disadvantage I'm not considering ?

[blackdaisies]

Maybe what you need is some ballast, a keel, daggerboard, or centerboard. This weights the boat down, plus the keel types prevent you boat from being pushed by waves from underneath. It stabilizes it. You are on flat water, but you need some wind resistance, so maybe its a simple fix,, make or buy yourself a portable keel, or daggerboard.

It's only a guess and you can experiment with a cheap daggerboard from wood to see if they work. I just read on another forum wood ones aren't allowed, but why would they out law wooden daggerboards?

[eponodyne]

Originally Posted by Fanie

Hi Guys,

Something has been nagging me for quite a while.

The power boat I have currently is a 5m500 semi cathedral hull, 2m wide. Draft is around 150mm and deck clearance is around 500mm. The 115 does up to about 70 to 75km/hr flat out. Very stable to walk on, in general not a bad rig for venturing onto fresh water.

Only thing that I find very irritating is that if the wind picks up on some of our dams, you have to abandon fishing and 'retire to the lounge' so to speak. Being a single hull there can be quite a bit of roll and the risk of a wave splashing in becomes a risk. The boat won't sink, it has enough flotation for that, but it would be a very unpleasant experience as you can imagine.

Our boats have high decks where you can walk on and fish from, similar to the bass boats. It just works better to stand on the boat instead of in it, especially since we lure fish and cast almost all the time.

Now since I got involved with you hooligans, I got a liking in the sailing catamaran hulls that are wide apart and offers the space and stability.

So here's what I was thinking -

Hulls similar to a sailing catamaran but shaped so they can plane. The two hulls fit on a trailer side by side and when you launch the hulls expand sideways so a gap is between them, the gap between the hulls has a trampoline one can walk on.

This would result in a wider boat offering more stability, and more deck space to walk on. The two hulls should also be lighter in weight which should make trailering easier. If one make the hulls longer it would add to stability and still be within the weight of a single hull.

Anything one would gain from a setup like this instead of the single hull ?

Any disadvantage I'm not considering ?

I have been pondering this for quite some time myself. Twin panga-style hulls, each narrow of beam themselves but between the two, they add up to a decent beam (Irrespective of the actual beam of the vessel as a whole).

I do think that wave slap on the underside of the bridgedeck would become an issue, perhaps even a serious structural issue. Perhaps a walkable trampoline isn't such a bad idea; at least when you fell (and fall you would) it would be onto something soft.

[Fanie]

Eponodyne, we don't really fall on our boats unless we really want to

I know the basic answers, but has never compared something like this under the same conditions. I was hoping that someone familiar woth both would come up with something.