With slim, light, flat-bottomed boats, the design limitations really kick in when you have waves of just the wrong size right on the beam. The flat bottom stays more or less flat on the surface of the water, so you roll appallingly with each passing wave. Not such a problem under sail because the sail keeps you at a steady angle of heel, but under oars the boat quickly becomes unmanageable.
I'd also note that free surface instability is very evident if you get water in them - I've had an involuntary bath as a result of that!
All the floor did was to bulge aft to create drag. The Lodestar's rigid transom, V-hull forward and very taught floor make it easy to plane with a light load. I'd doubt the Avon would plane unless the crew all jumped into the water, even then it would be more likely to just stand upright and destroy the outboard when it went under. I'd agree that the existing hull and transom won't work.
I wonder if you could find a hull from a scrap rib, cut out the bit you needSo much good advice and various exciting alternatives here...thanks for all the thoughts, and please chip in with any more.
Reflecting on recent years, I spent far more time tinkering than afloat, in various boats, so even though my eyes are popping out at the elegance of the Bolger designs and the idea of building one, I reckon I should try something modest.
I'm still tempted to construct a lightweight plywood slight-V hull that I can strap under the Redcrest, incorporating a transom that will eliminate the torque-driven hogging of the inflatable's hull.
I realise I could achieve that by inflating the fifty year-old tubes to the pressure recommended by Avon, but it wouldn't make the flat rubber bottom any better for speedy motoring, nor (I suspect) would the old boat live much longer, driven so hard. Whereas, with a new hull and transom....
...it's extremely appealing to think of a slouchy old grey round-tail jumping up on the plane and scooting along faster than it was ever designed to. It would also remain tough, practical and very cheap, but about fifty times more entertaining.
Is it best to start by constructing a mock-up that fits the form of the inflatable, then the real thing using the dimensions and curves learned?
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There must be loads of those in every boatyard. I know of at least 3. However, they’re usually pretty solidly constructed, for being pushed along by outboards 10 times Mr Crane’s.
How about 3x ?
And you can pick them up for relative peanuts too. You do need a wider transom for multi engines though. And here we all are telling you to build it narrow.
Really? I know they're getting a bit long in the tooth now, but my OB mechanic reckoned they were well worth hanging on to and spending whatever is necessary to keep 'em going because they're so much lighter than 4T engines, and they don't care how you put 'em down. Certainly, someone thought mine was worth nicking
Nobody seemed to want my Yam 2hp. Perhaps I’ll try again. I’ve got a Mercury 4 long shaft too. All surplus to requirements.Really? I know they're getting a bit long in the tooth now, but my OB mechanic reckoned they were well worth hanging on to and spending whatever is necessary to keep 'em going because they're so much lighter than 4T engines, and they don't care how you put 'em down. Certainly, someone thought mine was worth nicking
I have had both of them for about 30 years.That sounds very fair, I'll think it over.
To be honest, my eyes popped open at the age of them. I daresay new service kits keep them running fine with care, but, wow! I though my my circa. 2004 Tohatsu 3.5 was ancient.
I wouldnt bother. We had 4 tohatsus but could only fit 3 on the transom. The propellors were very close to hitting each other. Controlling them was borderline dangerous and while it did give more thrust the top speed gain was not worth the effort.
