planing vs semi displacment

[Guest]

After all i have read on here my conlutions are.

I still strongly believe that my turbo 36 will be more economical at a fifteen knot cruising speed than the same sort of size and power semi disp as i am on top of the water and the semi is pushing it out the way with still quite a bit still in the water.

In the roughest weather the semi will have softer landings and maintain a higher speed for longer.

i have witnesed so i know that the wash off a semi plaing is far worse at any sort of speed.

the planing hull is a bit more fun.

And my last point is that princess,sealine,sunseeker,fairline,windy,etc all use mainly planing hulls wich are all young people's dream boats. Where as hardy(but i do like these) aqua star,broom,etc use mostly semi planing hulls. so on this basis i will get a semi planing in another 20 years maybe not realy maybe 10

First of all you will be lucky to see 1mpg at 15 kts compared to Crackerjacks 1.5mpg 50% more. It takes a lot of hp to keep 10 tons on top of the water.

In rough weather the semi will maintain a higher speed period.

10 kts and the semi will give less wash fact.

I have cruised over 1000 mile on the east coast between London and Hartlepool over the past 7 years and that's why I now have an SD hull.

When I feel the need to go more than 20kts I hop in the rib or on my mountain bike, not quite ready for my pipe and slippers yet.

Last thing if you break down out there what type of hull will come out to rescue you .

Jonathan.

[baz1033]

well there you go then I stand corrected.

The last part of my post was a joke for some people, oh well

[Antares_9]

This is all very familiar, you could almost go through the thread deleting Planing and semi D and replacing them with power and sail.

[baz1033]

This is all very familiar, you could almost go through the thread deleting Planing and semi D and replacing them with power and sail.

Ah! now my wife sharron would love us to have a cat A motor sailor but i dont think i will get it on the plane

[Guest]

Perhaps we need a having a dig smiley.

[MY littleboat]

[

Ah! now my wife sharron would love us to have a cat A motor sailor but i dont think i will get it on the plane

Unless you hire one of those big Antanov's!!!

[Guest]

Barry. No one can see your planing hull but I suppose it can make you feel younger knowing you have one. Until you get the first big slam that jars your back and hey presto your back in your forties. SD is not an age thing simply a Sensible Decision.

[smitch6]

all these young wipper snappers with the planing hulls lol

let us old folks with the SD hulls have our pipes and slippers

[GrantS]

All this talk of planing is very upsetting you know................

[Guest]

Hi All

Last year was 1st year with present boat,been going through my log,april to october 1200kn=4000lts diesel,never mind plaining or s/d,think i need sail power.

[senator]

Interesting to know how many of those miles were at sea as that comes out at 1.4 miles to the Gallon, pretty impressive for a 43' boat that cruises at 23 knots.

The other thing in the SD Planing debate is what is a SD? Surely it is just a planing hull that doesn't plane very well. As far as I can find a boat is either Displacement (sits wholly in the water) or planing (moves an element of the hull out of the water to present flatter section to the water to promote a skimming effect.

Any Hull that is not displacement by default becomes Planing, Planing hulls can have a keel to promote stability but the better the hull the faster the boat will go. Anyone really worried about the sea can take solace in that a planing hull on the hump will go through just about anything as long as you have enough fuel on board. It looks ugly and drinks fuel but it will get you home, it is effectively doing what a so called SD hull does all the time just not as efficiently.

[Guest]

Interesting to know how many of those miles were at sea as that comes out at 1.4 miles to the Gallon, pretty impressive for a 43' boat that cruises at 23 knots.

yes i agree,when you convert to mpg, would think for sea work 1.0 to 1.2 max miles to gallon, 23rpm 17 to 20 nm we do enjoy going slow at times even when on a sea passage if conditions are nice(hot and calm) as were based on broards last year this would have helped.

[senator]

Anyone still questioning a decent planing hulls ability to cut it in the rough stuff might be interested in an article I have come across while looking for boats.

This may be of special interest to anyone stuck between the two but getting frightened by story's of frightening sea keeping. It is the story of someone who really does know what he is doing and has plenty of experience of all types of boat in all conditions, it covers him taking a Sealine F36 around Britain including force 8's and 4000 nm covered.

Sort of puts an end to whether a planing hull will do the job.

http://www.kimhollamby.com/blog/1999/04 ... -to-haslar