A question or two from 'the other side'

[kirielad]

A question or two from \'the other side\'

As a raggie (first post in the Mobo section) I hold my hands up and say straight off that I know precious little about the ways of the Sunseeker, and would appreciate a few 'knowledge gaps' filled in please.

Lately I have been 'helping' a bloke at work to try and find a Mobo (to be his first boat, 20k -ish budget, wants a 4 berth suitable for the occasional weekend away, Solent area - no further).

Whilst scouring boat adverts I quickly became aware of my level of ignorance when presented with the terms 'holeshot' and 'deadrise angle'. Could someone shine a light ?

Many thanks.

 

[bdsweeting]

Re: A question or two from \'the other side\'

Deadrise is the angle of the 'vee' shaped hull.

http://www.marisafe.com/news/articles.asp?mode=1&aid=114

holeshot - no idea, I thought that was something to do with drag racing.

 

[Lakesailor]

Re: A question or two from \'the other side\'

Holeshot

"The speed at which a boat takes off when put into gear quickly. A quick holeshot is useful when pulling water-skiers and wakeboarders out of the water."

My little boat steps up on the plane as soon as you open the throttle. Some cruisers take ages to get there.

 

[KCook]

Re: A question or two from \'the other side\'

It just happens that deadrise affects the holeshot. Here is another discussion on deadrise -

Deep V hulls

Kelly Cook

 

[Dave_Snelson]

Re: A question or two from \'the other side\'

Hi Kirielad - and welcome to "the dark side" /forums/images/graemlins/smile.gif

Lakesailors explanation of holeshot it perfect. Its the time it takes for a planing motorboat to get onto the plane from displacement, when you open the throttles.

Deadrise is more tricky. If you look at a motorboat from the stern when its parked on the hard, you will notice that the hull forms a V shape. Some mobos are deep V and the deadrise angle is steep - a deep V in fact as measured against the horizontal, just like my Windy. Other boats have a more shallow V. Generally it is accepted that the deadrise is measured about one-third of the way forward of the transom. As an aside, Fletcher boats developed what was known as the "Delta Pad" - they truncated the V at the stern, so if you looked at the boat from underneath it would appear to have a flat part where the V is cut off making a triangular shape. It was meant to improve holeshot and fuel consumption. It never caught on.

So which is the best? There is no real answer. Depends on what your friend wants. A shallow V has a better holeshot but slams and is uncomfortable in anything other than a low chop - imagine riding a tea-tray on rough water at 30 kts and you will know what I mean. They do generally use less fuel though.

What is important though is the "shape" of the hull underneath. Some boats that have a deep V have a bland flat shape with maybe two "strakes" that are meant to bite into the water on a turn. Strakes are moulded lines that run for to aft. More serious designers like Sunseeker (or indeed Windy) do things differently.

Here a piccie

On the other hand, a deep V will take longer to get onto the plane but once there is will certainly take on much rougher water.

If your friend is looking for a "performance boat" then Sunseeker is a good place to start. You can help him in many common sense ways, like looking for obvious GRP or gelcoat damage, and osmosis. As a yachtsman you would also be able to spot signs of misuse or neglect.

Tell him to get a survey done and while he is about it, tell him to take the RYA powerboat level II course to give him a good grounding. And then show him the ropes when it comes to water safety and common sense items to take on board. When it comes to this sort of thing, there are plenty of similarities between sail and power. I hope this helps.
Dave

 

[kirielad]

Re: A question or two from \'the other side\'

Thanks for the replies all, and sorry I didn't reply sooner - SWMBO , unfinished decorating + rainy weather over the last couple of days - need I say more?

Rob