CLE / Nose Cone / Transom pickup?

[RoyE]

I have a Piranha Espada 16ft (Belgian V-bottom ski boat) with a Merc Black Max 135 V6. I have a Bobs 6" hydraulic jackplate and I have the water scoops installed. However, since I have the Bobs lift which goes much higher than the previous CMC lift I'm having water pressure issues while still maintaining enough bowlift. Top speed when I'm alone in it is 70mph, with two persons about 64 mph and then I really really need the bow lift.

To solve the water pressure issue I could have the lower unit coned or I could install a transom pickup.

My concern is that since I'm running sub 80mph speeds and I really need the bow lift when running with 2 persons or more, a nosecone will probably only slow me down. That is why I figured i should stay with the standard lower unit and feed it water from a transom pickup.

My concern with a transom pickup is mostly where to mount it? When I'm running WOT not much of the bottom is left in the water. I'm afraid when I mount the water pickup near the V of the boat that it will distort the water flow for the prop. Does anyone have any experience with this? Attached is a picture of my bottom (best I have right now, can make better ones next Monday). I think I can maybe mount it on the inner sprayrail on the left, since the engine is offset to the right.



I found the thread of Mr. Demeanor which is really helpful in building my transom pickup if that is what I decide to do.

What are your opinions?

[Bodhi]

The last part about how Mr Demeanor rigged his is great advice, he definitely has his dialed in . Personally I don't think you need that in your setup. Above you stated that you wouldn't want a nosecone to slow you down...that wouldn't be the case at all. A nosecone will allow you to block off the side pickups and ram feed your water pump at the surface. Even though you don't plan on 80+, it's the low water pickup from the nosecone your looking for and the ability to surface the prop for less drag and better speed.

[whipper]

As bodhi already stated above LWP will help you with your water pressure running even or above the pad. Running an external pickup with a vee bottom like yours will not work as good as a Bobs Nose cone will. Its the prop choice that gives you lift not your gearcase very much. you will more than likely pick up speed and for sure you will have water pressure with a Low Water pickup setup over the large bullet on the stock case.

if you ran an external pickup because you run with very little hull in the water the only spot to put it would be on the pad. Yes you right it will interfere with the hydrodynamics of the pad. Its not worth it on a Pad vee hull compared to the low water pickup on the gearcse. On very few tunnel hulls its a different story if the application for more speed requires extreme prop shaft running heights. Such as the case for S&F member Mr Demeanors setup. But even then most tunnels run best with lwp gear cases as there setups dont require higher propshaft heights and trim to loose water pressure.

With a LWP cone on your case you would be able to run higher than even with the pad were your at in the pic and still have water pressure and with the right prop even more speed and lift.

VERY COOL BOAT BTW.

[Markus]

When I was a kid, I wanted a Piranha Espada.

[racervboat]

loose the passenger or get a diveorce or I love you honey LOL

[bigboy]

I would hang a Go pro on the back so you have an idea of the wetted surface.
Best to install pickup at portside for less distortion.

With a pickup you can mount the engine even higher.

I wouldn't even consider a nosecone.

[RoyE]

Thank you all for the nice and interesting comments. I was at my boat today and found that there is no way I can mount an external pickup on the transom without interfering with the water flow to the gearcase/prop. I am more and more leaning towards a nosecone..

As bodhi already stated above LWP will help you with your water pressure running even or above the pad. Running an external pickup with a vee bottom like yours will not work as good as a Bobs Nose cone will. Its the prop choice that gives you lift not your gearcase very much. you will more than likely pick up speed and for sure you will have water pressure with a Low Water pickup setup over the large bullet on the stock case.

if you ran an external pickup because you run with very little hull in the water the only spot to put it would be on the pad. Yes you right it will interfere with the hydrodynamics of the pad. Its not worth it on a Pad vee hull compared to the low water pickup on the gearcse. On very few tunnel hulls its a different story if the application for more speed requires extreme prop shaft running heights. Such as the case for S&F member Mr Demeanors setup. But even then most tunnels run best with lwp gear cases as there setups dont require higher propshaft heights and trim to loose water pressure.

With a LWP cone on your case you would be able to run higher than even with the pad were your at in the pic and still have water pressure and with the right prop even more speed and lift.

VERY COOL BOAT BTW.

Thank you for the compliment, just like Markus I wanted a Espada since I was little. When I was 18 I bought one, and after few years of boating with it I replaced the transom, stringers and floor and replaced a 70 hp OMC eventually with a 135 Merc V6. I built it quite heavily since the waters can be rough here and I want to be sure it is bullet proof. The Espada is in no way a very high performance hull but I love the boat and like getting the max out of it.

loose the passenger or get a diveorce or I love you honey LOL

@bigboy the Go pro is a cool idea to get an idea of what is actually going on.

[RoyE]

Went out last weekend and mounted an action cam on the back of the boat.

Have made a short video. Ran two different props that day: TXP OT4 26p and Hoss Hyperdrive 27p

Here is the transom shot:


Here are two videos of the boat running

TXP OT4


Hoss Hyperdrive


In the videos you can see a strange spray that is offset to the port side of the boat. It is not caused by the prop. I found out that it is actually water bouncing of the front of the gearcase into the air, strange! Never seen this on other boats. You can see it in the transom shot.

I think I will be ordering a Bobs nosecone soon boat ran great but again ran out of waterpressure

[W2F a V-King]

Have you tried a chopper style propeller? Should get you some bow lift if that is what your looking for, and plugging the top 3 holes in your lower unit might help some with your water pressure.

Something to try before you go to the expense of coned lower unit.

[RoyE]

I once ran a 26 big ear and a 28 big ear chopper. I found that the TXP OT4 has at least the amount of bow lift that the choppers have. Last weekend I ran the Hoss Hyperdrive for the first time. I think it has less bow lift than the TXP OT4 and some transom lift. The boat runs flatter on top end and seems to run 'higher' on the water, turned out I made my fastest runs with the Hyperdrive, both alone in the boat and with 2 persons. I once ran a Mercury Humpback cleaver, which had even more transom lift and its top end numbers were similar to the Hyperdrive. I think I may need less bow lift than I initially thought, which is why I have more confidence in the nosecone. Taking into account the above comments, I think I'll try it.

[RoyE]

I ordered the Bobs nosecone, installed it and ran it for the first time last weekend. I am very happy with the results. The boat accelerates faster, is more stable, less chinewalk and about 3-4 mph faster than before.

I tested three props: TXP OT4 26, Steve Smith Offshore Cut 28p, Hoss Hyperdrive 27p.

I did notice that I lost some bowlift, the boat tends to run flatter now with increased stern lift. I can run the TXP OT4 with the prop shaft about 3/4" inch above the bottom (as high as it can go now) and still have enough lift with neutral trim at top speed (about 72 mph).

The Offshore cut did not have enough lift for my boat at that height, so I had to run it lower, which resulted in less speed. The Hyperdrive was just a bit faster but I needed some positive trim to get there.

I am very happy with how it turned out, thank you for the suggestions

[W2F a V-King]

Nice Work!!

Persistence pay's off for sure !!

James

[RoyE]

Just to follow up somewhat more:

I tested the boat with 4 persons. I used my Trophy Plus 26p. I had to run the engine somewhat lower compared to when I'm alone in the boat, but definitely not lower than previously without nosecone and I still had plenty of bow lift. The boat ran great! I post this follow-up in case anyone is in the same situation as I was before