tri-hull or v with sponsons?

hi

I have a 1977 5.2 terry bass boat. just wondering if anybody was familiar with this hull. I thought it was a tri-hull, but my local marine guy said its a v-hull with sponsons. anybody know?

 

Do the "sponsons" carry all the way to the transom? (i.e. hull bottom at transom looks like an upside-down w). If yes, it's a tri.

 

To flyguy,
all the above are, more all less, accurate.
A tri- hull is, after all, three hulls going inthe same general direction.
However, as the outer hulls are moved closer and closer to the centre hull
- by the designer and/or designer - they will start to be referred to as
" sponsons ".
The words dont really matter.

The real issue is: are you getting improved stability - compared to your
experience - in other boats ?
- Without getting any increase in slamming, in choppy conditions ?

There are boats that can do both these things - at the same time.
With out a close, hands on look, it's hard to say.

 

P.S. To: flyguy.

Oops !

The 5th line to: Tri-hull or V...
Was intended to say, "........builder and/or designer..."

 

Yes you have a tri-hull...I have a 1977 Terry Tri-Hull bass boat

 

There are many variations on this theme, but mostly it's a gimmick, unless extra drag and decreased turning ability are your goals. You can call it whatever you want, I've heard several over the years.

 

My interpretation of tri hull is that all three hulls are in the water when underway .

Sponsons are out of the water when the craft is at speed. Think of the typical RIB.

Conventional small craft hulls with sponsons look like the wylie skiff

 

You can attempt to justify these drag inducing protuberances anyway you want, maybe even inventing some new syntax to describe them, but they're what they are and it still doesn't matter, as they're not especially efficient.

 

Why are these done like this? Wouldn't they act like a scoop in reverse?

 

The longer bottom is like a longer wheelbase on a car. Greater pitch stability. And if one backed fast they probably would. I see it as a trade off. I would probably just make the boat longer by putting the transom at the trailing edge of the bottom. I really like the Wylie skiff. The water rolls out from the chine area whereas most planing types "spit" water out at high velocity and then the wind makes lots of fine spray of it. I'd consider buying one of these boats if they were bigger. Should have excellent mid speed performance.

 

It is a very well thought out boat. Must be expensive for its size.

In the picture you can see what is wrong with all modern outboards. The motor clamp is just too big and always rests half in the water, turning it into a barnacle covered textbook example of marine corrosion.

Its a shame... old 40 hp motors , with classic screw clamps had compact mountings that were clear of the water. Seems the only solution is to buy a 25 inch leg then jack up the transom 5 inches to keep the clamp clean. Obviously not attractive.

What are these motor manufacturers thinking ?

 

common parts usage for a range of engines
The trim unit on those 40 ish and above engines for all other manufactures is the same part made by a Jap company ( and they are not repairable)

 

Yah...I see.

Those 50 hp yamaha two strokes that are still new ,in shop backrooms, are nice engines. The local dealer has one. I really should buy it before they disappear.

 

I have long thought that tri-hulls have the potential to be very good offshore boats, but not the cathedral hull types with terminating tunnels, or shallow tunnels that bottom-out easily. These are spine destroyers that are generally unsuited to anything more than small chop. There have been some quite successful boats with deep tunnels built, but generally speaking they have too much wetted area to be really efficient boats, but offsetting that they require only one engine unlike cats.

 

Looking at my Y50, I would guess that it is to fit the tilt mechanism with a better moment arm to lift these motors under thrust loading. That takes a lot of power when underway. Had to replace my tilt motor because of the problem, once already and my boat does not stay in the water.