Switzer, Hydrostream, Porposing, Jackplate

**Pickinator** · 09-08-2009, 03:21 PM

Hi:

This is the first time I've started a threat here at S&F. I wanted to ask a couple of questions.

I have 2 boats;
(1) a 1980 Switzer with a 260hp Mercruiser IO running a high-Five 21pitch prop.
(2) a 1977 Vector with a 150xr2 Merc with a 19pitch prop.

The Switzer tops out at 67 mph. It used to porpose from about 20-25 mph until I attached a "mantaray-looking" fin to the cavitation plate. Now I can't make it porpose even if I wanted to. I don't like the thing but there is no question that it has helped. I was considering taking it off and puting on smart tabs. Before I put on the mantaray the boat topped out at 68mph. I lost 1mph off the top end. Also noteworthy: The boat doesn't turn as well with the fin. There is very little that I can change with the IO set-up other than the prop or the addition of tabs. Do the mechanical people here at S&F recommend tabs over a foil on the cav plate. Will it bring back better turning ability.

The Hydrostream came with a manual jack-plated Evinrude 175hp that died. I couldn't give it away so I sold it as scrap for $45. I still have the cover. Ha.

I bought the Merc 150hp off of eBay and stuck a lot of money into it. It runs quite nice and tops out at 60mph. It doesn't porpose and planes out nice and quick. I don't use the jack plate and have it mounted straight onto the transom. The boat turns very well. When the Evinrude 175 was on the jackplate it cavitated on very gentle turns and topped out at 53mph. The boat probably has more in it as I haven't experimented with props. It came with a 15-pitch and ran too high with the rpms. With the 19-pitch, which is the only other prop the mechanic and I tried, it runs nice.

I was wondering why jack-plates are so highly prized. The old jack-plate made the boat hard to turn and made the bow rise more. Is there anything the mechanical folks here would try on this Vector or leave it be.

I am not unhappy with either boat but I'm just curious if there is anything anyone would try with either of these boats.

I am also looking to purchase an open bow for carying more people. I'd again like either a good used Switzer or Hydrostream.

Thanks for any suggestions and for reading my first thread. Note: I have another addiction besides boating; - drumming.

Pickinator (Jim)
hound@nnex.net

**Wizard** · 09-08-2009, 03:32 PM

Silly rabbit trim tabs are for idiots!

Honestly I'll blather about your Stream first. I'm almost positive if I put my motor on my transom my porpose would lessen somewhat. But if I put my motor on the transom I could not run the engine height I need. To really run fast speeds the propshaft needs to be equal to or higher than the pad. Running 60 is easy with the prop buried. To run 80 you need to raise it. Putting a big V6 higher and farther back makes for handling problems as the hull was not designed for it. So do you want to go fast or do you want perfect handling?

As to your Switzer I would say the smart tabs would be a good investment. The big cav plate fins work but if you have your engine very low they will drag in turns which causes your problem. The smart tabs push up with water pressue lessening downward force. As you turn each lessens individually so you will see an overall good improvement in handling with very little loss of top speed.

Trim tabs are not a new invention. They have been around for decades. Offshore race boats use multi-thousand dollar K-planes. They do many things other than stop porpose. They are excellent for rough water keeping the bow down without using negative trim which tends to plow the nose. They increase holeshot by many factors. Yet in some cases they may slow down the top speed by I have not seen it with my simple, inexpensive smart tabs.

Just be preparred to take some heat from those with closed minds.

**oldskier** · 09-08-2009, 03:37 PM

Geez Wiz, it's an EPIDEMIC!

**Pickinator** · 09-08-2009, 03:52 PM

I think the Switzer will get the smart tabs and I'll take the heat. Can the heat be any worse here then that which one would receive for using a cavitation plate fin.

I like the way the Hydrostream turns now and will sacrifice top end for good handling. Would I see an improvement by switching to a 23-pitch prop. I would call a +4mph top end without a drop in hole shot performance an improvement.

I also have 3 teenagers (and a 6yr old) here and I guess I don't need to see them doing 80.

**rdkvector** · 09-08-2009, 03:59 PM

For a Vector, flip your jackplate, bring it close to the transom. Then you can adjust the height until you find the sweet spot. Vectors have built-in setback with the notched transom design. They don't like setback but they do like engine height.

**oldskier** · 09-08-2009, 04:06 PM

Originally Posted by Pickinator

I think the Switzer will get the smart tabs and I'll take the heat. Can the heat be any worse here then that which one would receive for using a cavitation plate fin.

Nobody here uses a cav plate fin that looks like a "Doel Fin" or a "Stingray" or a "Manta Ray" (Except me, just put one on my Powercat this weekend, works great!)...they all bend up sheets of aluminum that do the same thing and bolt 'em on but they're "custom built".

(oooh...did I say that?....

....donning flameproof underwear....

)

**transomstand** · 09-08-2009, 04:21 PM

I thought we settled on canards on the last thread

**200VEGAS** · 09-08-2009, 04:28 PM

how many rpm are they both turning now, and do you know what a choppper is, and look at a bobs machine shop type plate as well so you know what all's available to you

**Pickinator** · 09-08-2009, 04:41 PM

The Switzer's Mercruiser tops out at about 5200rpm. Its a 350 ci with a Holly 4 barrel. _Old school but it honks

I'm not positive but I think the Vector tops out at about 6300+rpm and I've never fully trimmed it. I stopped at 60mph. I don't think it has much more in it though.

**transomstand** · 09-08-2009, 04:43 PM

I think the first thing you need to do is determine some goals for these boats that will suit your needs. Tell us more.

**200VEGAS** · 09-08-2009, 04:51 PM

does the hydrostream have kill switch, dual cable steering, and a good transom..

**Pickinator** · 09-08-2009, 06:25 PM

No kill switch on the hydrostream
The floor and transom seem fine. It is original, no soft spots. The 150 seems to do very well for it.

{{I know a guy that has/had a hydrostream voyager that ran fine with it's original 175hp Merc. A friend talked him into a newer 250hp Merc and he was testing it hard through a tight turn and heard a loud crack. He says that he cracked the hull? The boat is now retired in front of his tavern as a conversation piece.}}

The Switzer is very sound as well.

I'm basically just looking to tweak them a bit.

I am going to go with the smart tabs for the Switzer and retire the manta fin. The Switzer is also getting a new stereo.

I like the Hydrostream with the jack plate off. I don't think it needs tabs as it planes out quick and doesn't porpose. I am just considering a higher pitch prop than the 19 it presently has. No stereo for it.