Tandem multihull

[warren mosler]

I just took a ride in the latest from
St. Croix. It's nothing more than two dingy's,
rigidly connected by an old Hobie mast,
38ft loa, with an 8hp outboard.
We went outside the reef into some 2-4 ft seas at about 5-7 kts.

The ride quality was phenomenal.
Pitch motions were both subdued and non boat like
in a good way. It was a dramatically reduced and far
different pitch than in a 'normal' 38 ft hull of any design.

Into head seas the forward dingy kept it's nose up, even when coming down the backside of a wave, and didn't 'flip up' going into a wave. The trailing dingy stayed relatively level and moved mainly vertically with very different accelerations than experienced in other boats. more like a long wheelbase bicycle going over an undulating sandy surface.

Roll was subdued vs what it would be
like in either dingy alone as well.

Anyone ever seen or tried something like this?
Am I missing something?

Yes, it's going to be relatively inefficient, but with today's light weight
structures it's seem efficient enough to be worth the vastly superior ride quality?

And it won't have much load carrying capacity for its loa, but again for passengers it doesn't have to carry all that much load?

I'm wondering how it would scale to, say, two 35' hulls maybe 50 ft apart?

And when diminishing returns set in from the improvement due to the
'wheelbase' effect?

[Doug Lord]

Very interesting and very wierd-thanks for showing us! Worth some thought-I think.

[warren mosler]

Originally Posted by warren mosler

I just took a ride in the latest from
St. Croix. It's nothing more than two dingy's,
rigidly connected by an old Hobie mast,
38ft loa, with an 8hp outboard.
We went outside the reef into some 2-4 ft seas at about 5-7 kts.

The ride quality was phenomenal.
Pitch motions were both subdued and non boat like
in a good way. It was a dramatically reduced and far
different pitch than in a 'normal' 38 ft hull of any design.

Into head seas the forward dingy kept it's nose up, even when coming down the backside of a wave, and didn't 'flip up' going into a wave. The trailing dingy stayed relatively level and moved mainly vertically with very different accelerations than experienced in other boats. more like a long wheelbase bicycle going over an undulating sandy surface.

Roll was subdued vs what it would be
like in either dingy alone as well.

Anyone ever seen or tried something like this?
Am I missing something?

Yes, it's going to be relatively inefficient, but with today's light weight
structures it's seem efficient enough to be worth the vastly superior ride quality?

And it won't have much load carrying capacity for its loa, but again for passengers it doesn't have to carry all that much load?

I'm wondering how it would scale to, say, two 35' hulls maybe 50 ft apart?

And when diminishing returns set in from the improvement due to the
'wheelbase' effect?

While likely to not be all that fast/efficient, the attached Tandem Ferry concept should have a far superior stability, sea worthiness, and a very user friendly ride?