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Old 24 September 2016, 16:38   #21
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Originally Posted by Pikey Dave View Post
Ahh! Now we're getting into the black arts😄 most folks think that a prop is a prop is a prop, nope! Props are like car tyres, good, bad, indifferent. By altering the geometry of prop blades, different properties can be bestowed on the prop. A prop can be bow lifting in that it hooks in & pulls the stern down, thus lifting the bow. Other props try & "climb" out of the water, thus lifting the stern (handy on twin engine installations with heavy sterns) this lifts the stern & brings the bow down. This can all be a function of number of blades/rake/cupping/blade shape & size. The Mercury site has a very good section on props & how they work.


Lions led by donkeys
will have a look at their site
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Old 24 September 2016, 17:10   #22
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As unlikely as most other deep V Ribs of a similar size but certainly possible, it is in anything in the right/wrong sea!
I disagree. Firstly, since the Destroyer range was introduced all Humber boat have massive lift in the bow. The hulls are made with very wide flanges and outward of that is the tube, this feature effectively forms a large rim around the boat so as the bow buries the flange/tube creates huge lift as the water is displaced upwards. Secondly, stuffing a boat is really driver error so, as I said, you'd have to be driving really badly to stuff a Humber.

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Good fun though
I disagree. Taking on a ton of water in a matter of seconds is a serious risk to boat and crew.

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As for a beam on sea, the destroyer with few chines and a high sheer bow will have a fairly wet ride compared to peers with lower now or more chines.
I disagree. The Destroyer has a particularly dry ride. The flanges previously mentioned are actually angled downwards and water which is rushing up the hull is redirected downwards by the flange.

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It's a bit like the Delta Dash. The wave will rush up the hull and is thrown in a more upwards direction for the wind to blow it in your face.
I disagree. It's nothing like the Delta dash.

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A lower bow (tubes) or chines will force more spray out at a lower angle. Drier ride.
I disagree. The water being forced out is caught by the wind and comes aboard as spray so more spray rails won't necessarily make for a drier boat.


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More chines give lift and substantially more impact to a smooth hull.
Fixed it for ya.

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So a destroyer head vs an ocean pro (more chines) in a head on sea may give a slightly more comfortable ride. But you'd be sat ever so slightly lower in the water using a little more fuel.
Would you? A destroyer has a planing pad....
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Old 24 September 2016, 17:35   #23
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next question whats a bow lifting prop and whats different from a normal prop
As Mr Pikey Dave said, there is plenty of variation in prop performance even though props may have the same diameter and pitch. It's not a black art though.

Bow lifting props do pull the stern down and, in general, they achieve this by having a good grip on the water. The blades are curved or spoon shaped to some degree. A secondary benefit of this is that they tend to grip the water better when near or at the water surface. It's perfectly possible for a prop to run partially submerged and still be completely effective if the blade is the right shape. Note, I'm not talking about surface piercing props, which is another area altogether.

The reason they are good in a head sea and produce a substantially more comfortable ride is because they are capable of powering the boat while operating close to the surface or semi submerged. When the boat is skipping over waves and taking the odd jump, a prop which keeps the boat powered will prevent the boat from losing drive and slamming as it lands. Some well designed props are capable of driving as soon as they re-enter the water when a boat as jumped off a wave and they give grip and drive before the hull actually lands. Conversely, I've seen props which are so poorly designed they break away their grip very easily and are incapable of producing drive until the throttle is closed and the boat speed has dropped below planing speed.

I hope that clarifies to some extent for you Mr Breezeblock.
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Old 24 September 2016, 20:48   #24
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I disagree. It's nothing like the Delta dash.


JW,

That's good info you posted.

Since your familiar between the two could you please describe the differences with the Delta and the Destroyer?
Are you also familiar with narrow hull Tornado's (non-Chinese) and how do they compare to the two above.

Sorry to ask this but these three seem to get lots of similar comments about their good sea keeping qualities and similar characteristics.
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Old 25 September 2016, 02:11   #25
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Originally Posted by jwalker View Post
As Mr Pikey Dave said, there is plenty of variation in prop performance even though props may have the same diameter and pitch. It's not a black art though.

Bow lifting props do pull the stern down and, in general, they achieve this by having a good grip on the water. The blades are curved or spoon shaped to some degree. A secondary benefit of this is that they tend to grip the water better when near or at the water surface. It's perfectly possible for a prop to run partially submerged and still be completely effective if the blade is the right shape. Note, I'm not talking about surface piercing props, which is another area altogether.

The reason they are good in a head sea and produce a substantially more comfortable ride is because they are capable of powering the boat while operating close to the surface or semi submerged. When the boat is skipping over waves and taking the odd jump, a prop which keeps the boat powered will prevent the boat from losing drive and slamming as it lands. Some well designed props are capable of driving as soon as they re-enter the water when a boat as jumped off a wave and they give grip and drive before the hull actually lands. Conversely, I've seen props which are so poorly designed they break away their grip very easily and are incapable of producing drive until the throttle is closed and the boat speed has dropped below planing speed.

I hope that clarifies to some extent for you Mr Breezeblock.
I've only had a decent size boat for 6months so i am still picking up on bits and pieces i had no idea that there was so much differences in prop design
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Old 25 September 2016, 02:47   #26
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Originally Posted by jwalker View Post
I disagree. Firstly, since the Destroyer range was introduced all Humber boat have massive lift in the bow. The hulls are made with very wide flanges and outward of that is the tube, this feature effectively forms a large rim around the boat so as the bow buries the flange/tube creates huge lift as the water is displaced upwards. Secondly, stuffing a boat is really driver error so, as I said, you'd have to be driving really badly to stuff a Humber.



I disagree. Taking on a ton of water in a matter of seconds is a serious risk to boat and crew.



I disagree. The Destroyer has a particularly dry ride. The flanges previously mentioned are actually angled downwards and water which is rushing up the hull is redirected downwards by the flange.



I disagree. It's nothing like the Delta dash.



I disagree. The water being forced out is caught by the wind and comes aboard as spray so more spray rails won't necessarily make for a drier boat.





Fixed it for ya.



Would you? A destroyer has a planing pad....

Thanks for that Poly
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Old 25 September 2016, 04:57   #27
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thanks for that poly
You're welcome.
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Old 25 September 2016, 05:21   #28
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Since your familiar between the two could you please describe the differences with the Delta and the Destroyer?
I have limited experience of the Delta Dash and it was a long time ago but my recollection is that it required a fair bit of power to get the hull planing and that it was capable of carrying a fair load in the bow area.


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Are you also familiar with narrow hull Tornado's (non-Chinese) and how do they compare to the two above.
Nope, sorry. I never been in one. I considered one and went to the factory and saw them being made but I also went to Humber since they were both in Hull (the town!) They used polyurethane fabric rather than hypalon and had to be particular about the gluing. I recollect thinking that the deck ply seemed a bit thin for the job. I also had a conversation with them regarding a canoe they had built, apparently it didn't work out too well and they found it tricky to do, well, I've built several canoes and they're pretty easy to build so I was left in some doubt about their fibreglassing ability! Since then I've come across a few of them and the fabric has bleached out pretty badly and they looked rather sad. There is a story about them using a hull from a Phantom mould they borrowed but the story I heard was that they somehow hashed the deal and weren't fair about it. That's hearsay though so may or may not be true.
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Old 26 September 2016, 14:19   #29
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Well...went to check the boat. Was in a rater sad state:

- jumped on the deck, felt solid but the plywood is for sure partly rotten(was able to loose some plywood close to a badly sealed inspection hatch in the bow(don't think its Humber original)

- transom felt solid, no cracks in grp, but no guarantee the plywood is solid.

- outside of hull plenty of wear and tear but not exposed grp or relevant visible repairs.

- tubes, 1995, looks bad,much worse than my SR 5.4 navy from 1993. As can be seen on photos...don't know if can expect much life from them even with tlc. Guess a new set would be like 4000 pounds?

-engine started instantly, but its a 1989, not much value.

As it seams like there has most of the time been more or less water in the under hull due to badly sealed deck, guess the longitudinal stringers can also be in bad shape if they are of wood.

Value wise guess engine would be like 700 pounds and the hull like 1000 or maybe zero?
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Old 28 September 2016, 15:50   #30
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Originally Posted by jwalker View Post
I have limited experience of the Delta Dash and it was a long time ago but my recollection is that it required a fair bit of power to get the hull planing and that it was capable of carrying a fair load in the bow area.


Nope, sorry. I never been in one. I considered one and went to the factory and saw them being made but I also went to Humber since they were both in Hull (the town!) They used polyurethane fabric rather than hypalon and had to be particular about the gluing. I recollect thinking that the deck ply seemed a bit thin for the job. I also had a conversation with them regarding a canoe they had built, apparently it didn't work out too well and they found it tricky to do, well, I've built several canoes and they're pretty easy to build so I was left in some doubt about their fibreglassing ability! Since then I've come across a few of them and the fabric has bleached out pretty badly and they looked rather sad. There is a story about them using a hull from a Phantom mould they borrowed but the story I heard was that they somehow hashed the deal and weren't fair about it. That's hearsay though so may or may not be true.
Sorry JW, I just saw your post to me. Thank you and it's always good to pick a brain and get some added info. Cheers.

Seems hard to go wrong with a Destroyer with the availability, performance and prices they're fetching. Having Humber in the UK and still going strong makes it even more desirable compared to the rib Co.'s who no longer exist or are overseas.
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