TOPIC: What to expect from this combo?

Hi to all,
It took almost 2 years to have my french wooden racer repaired/restored. Thanks to "Peter1708" i found out that my french build boat is actually a 1991 Ken Basset Rascal. At least 5 of them were made by "De hart Miltenburg- Fontenille France". The transom is sized for long shaft motors and the last time i ran it with a Merc 1000, 1965 and earlier a Merc 1000, 1963. That combo`s ran awesome but not so fast. About 50 mls/h.

Earlier this year I had the carburaters and fuel system revised of my Merc 1500 J block. The motor is also re- painted but the cowl and decals are still in original condition. I have put the short shaft motor on the long shaft transom after changing the lower part for a Merc 850Xs with LWPU. The gear ratio is the 850XS. A 24 pitch cleaver is on. { pic} No power trimm is added.

Within 2 weeks or so I will have a first try on the water. So here comes the question....see subject.

Thanks, Taco

pic 3.0

Like Fast and Loud Richard Rawlins would say.."let her rip tater chip"! You will be in the 70's now!

Oh my goodness, nice, nice set up!! I am very envious and can't wait to see the numbers you run! That motor looks real good on her, be safe out there!

I have to agree with Robby, you should reach the low 70's, depending on set up. As a data point, my '64 1000 Frankenmerc shorty just hit 57mph (well, 56 and change on the GPS, running a 22 in chopper, but I tend to play fast and loose with rounding up .

Would love to see some video of her running if you can get it.

Good luck and stay safe,

Pete

Nice! I was just looking at the 85XS low water pick-up...right off the bottom of the bullet. That should allow you some flexibility on final mounting height and looks pretty good for starters. As all speed demons know - trim tabs help boats plane off, but if they are fixed or spring loaded, they scrub off some speed. Others should chime in here, but don't the V-6 people sometimes use that special metal tail fin on the motor with down turned fins (made of aluminum) to cup the water and help plane, yet once planed, it runs well above the water-line and therefore - no drag? ...just some thoughts.

Very nice rig!!
Dr.Go! (Mark)

Dr.Go! wrote:

Nice! I was just looking at the 85XS low water pick-up...right off the bottom of the bullet. That should allow you some flexibility on final mounting height and looks pretty good for starters. As all speed demons know - trim tabs help boats plane off, but if they are fixed or spring loaded, they scrub off some speed. Others should chime in here, but don't the V-6 people sometimes use that special metal tail fin on the motor with down turned fins (made of aluminum) to cup the water and help plane, yet once planed, it runs well above the water-line and therefore - no drag? ...just some thoughts.

Very nice rig!!
Dr.Go! (Mark)

JMO, but "Whale Tails" are only OK for a small number of boat motor combo's, and ugly as it comes, but not this boat. Nothing wrong with tabs and actually will help the rear hull lift more out the water, so reduced drag hull. And will control/stop chine walking, porpoising. Also get ya a stable ride. Have fixed on my Flatty OB (avatar). If they slowed ya down, why do drag boats have full width tabs?

What a Merc LWPU looks like.

Hey Taco! Is that a original 74 XS Blue stripe J block? Had a 74 XS on a 74 Switzer SS17. Only had horizantal trim rams, no tilt. Ran a 14x28 cupped and got a solid 73 mph out on it! Had to put the newer Red stripe Merc XS decals on as matched the boat. Damn, it was a real beast!

I agree on the "not so attractive to me" regarding motor tail fins. I was only referring to one type that the V-6 outboard high speed drag type crowd uses on flat pad bottomed V-bottom boats that are always changing trim angles to "fly" the boat without using trim tabs. I can see trim tabs being the solution for many boats and did not want to give the impression they don't work to resolve handling problems...however - notice that the full width trim tab on the yellow boat still has a linkage to adjust the amount of down pressure...I would assume more when planning with that much big block motor weight in the back...and assume less depth of pressure at speed...but also these big time drag boats have tons of HP and likely want to blow over without proper trim tab pressure and help prevent bouncing. Super HP drag boats need control over concern of trim tab drag...but hydrodynamics says the more stuff sliding through or over the water, the more drag... that is why one of the fastest hulls is a blown 3-point hydro at speed that rides on two front sponsons or even on the tips of fins on the sponsons and the bottom of the prop with the entire boat not touching the water so trim tabs no longer touching...everyone needs to find what works on their rig with their set up and how they like to run. Safety first so we get to do it again and again. just was thinking if low hp rigs use a deep running spring loaded trim tab, they may scrub speed. Notice that a modern I/O has fiberglass extensions of the hull that are concave downward to help plane off...BUT they are NOT flush with they hull bottom. The are many inches above the bottom running surface so that when you are planed out, they no longer touch the water to avoid the loss of performance due to drag.

This?.."notice that the full width trim tab on the yellow boat still has a linkage to adjust the amount of down pressure.."

There all controlled by a foot or lever left side, up down. Not "fixed". Control arm left side through hull.

Thanks for the response on my topic. I am not sure if I need the trim tabs but they do a very good job on my chris craft silver arrow so i bought a similar set for de Rascal boat. They can be set to 5 different positions and work automatic.

The Mercury is an original 1974 blue stripe J block with serial number 3912849 and the "J" stamped in the block. Short shaft and the original lower part is there too.

I need to find out what prop works best but they are very hard to find over here. I was lucky to have found the 24 cleaver.

Since e bay is using the global shipping programm I have to pay more for shipping, handling and tax than the costs of the purchased items.

Taco

Hi Taco!
One thing to be aware of is that the Merc XS low water pick-up gear cases are designed for use on tunnel boats and other negative trim style applications.
With a flat-bottom or vee-hull that uses positive trim angles, there is a risk of cooling water starvation, so keep a extra close eye on the water pressure gauge when used in these applications.
Bob's Machine sells a great nose cone kit with a low water pick-up designed for vee-hull and flat-bottom use.
doc

On props? Hard to find even here what needed. I ran a 14x28 cupped SS 2 blade and ran around 6300 R's. Of course that was with good gas and timing up in the 70's and prop then was $300. Now I'd stick with 21 degrees, not even standard 23 with the gas now. Melted a piston "twice" by going to far or wrong gas used.

But that said, as you have the 24 Cleaver now just go ahead and try it out. Just watch the tach and see what R's. I realize your not looking for that last 1/10th increase MPH, or a impressive rooster tail, so run the motor level, then no sweat the LWPU like Doc said (and true). Don't know the weight the boat, but it might be just the ticket. You will know ay more when ya "get wet".
Wish the best, and if a bigger prop needed, run it by us and maybe we can find what wanted, get it, and send it to you and save some bucks shipping. One never knows! I've sent stuff over seas about the size a prop box by ship (cheapest)and got it in there 3 weeks.
And more pix and a vid needed the boat! Good Luck!

Also a link on XS Mercs...

www.screamandfly.com/archive/index.php/t-268577.html

Probably why the Merc LWPU was designed (negative angle). Heres some pix the "Switzer Wing" and I know Bobby Switzer personal and still at it! A story him, and pix the "wing".

"The Day I Flew a Boat" by: Robert Switzer It all began with a phone call, (person to person) to me, Bob Switzer, from Carl Kiekhaefer, President of Mercury Marine. The date was July 17th, 1962. The meat of the call was a request for Switzer Craft to build a boat for twin Mercury 100 H.P. outboards that would exceed 100 M.P.H. on water. The call was impressive. Imagine ... out of hundreds of boat builders, we were called to do this project. We immediately began designing our first effort based on the pattern of the Switzer Hydro Cat (commonly referred to as the "Switzer Wing"). In 1961, the Switzer (U4) wing was a major breakthrough in the twin engine Stock Outboard Pleasure Craft Class U. (Unlimited engines but required to be a minimum of 15 feet in length.) The first Switzer Wing was built in 9 days, just prior to the Winnebago Outboard pleasure craft event, where the Switzer Craft Wing finished first overall, and the next two classes were also won by other Switzer models. The U4 was the first Cat to exceed 80 M.P.H. with only a pair of 76 cu. in. 80 H.P. Outboards. Our first new design developed to meet Mr. Kiekhaefer's request was not a complete success. At speeds of over 85 M.P.H. the bow had a tendency to kite or "bow up" (a feared maneuver of every driver). In late August, we tried a new hull concept, mounting the engines mid-ship in a hull much like the Hickman Sea Sled. It featured square simple lines and a shovel nose. We hoped that the engines forward could control any bow lift tendencies. Much to our regret the trial runs showed that the thrust of the propellers forward and under the hull clamped the back of the boat to the water and drag was too much for our twin 80 H.P. Mercury's to overcome in the initial plane off. Time was slipping away, the leaves were turning into their fall colors and we estimated approximately five weeks of open water to test on the Fox River near our plant. A decision had to be made... Do we call Mr. Kiekhaefer and postpone the project until spring, or do we keep going "right up to the wire" as the saying goes. The decision was made! Keep going! My brother, Dave Switzer was the designer in charge of the construction phase of this project. He knew that now the pressure was on to design and build that 100 M.P.H. boat in minimum time. Russell "Pop" Switzer, a pioneer in light aircraft and sea planes since World War I, injected some new ideas he had long thought were necessary to control a boat at flying speeds. Dave welcomed these new ideas and also accepted a weight distribution change that I had recommended. We also concentrated on making a cleaner air-flow version of his original U-4. Several days later the materials were flying into shape and the U-6 hull was finished in record time. With time running out fast it was rigged for the first test runs. The time was now! We proceeded to the test area on Nov. 29th, 1962, only to find that there was a 1/4" of ice on the river, stopping all progress. The weather reports promised warmer weather for the next day. All was held in readiness. November 30, temperature 45° -Sky clear -water open and calm. Time, 10:00 A.M. we launched the U-106. I got into the enclosed plexiglass cockpit (much like the capsule boats of today), checked out all instruments, fired up engine #1, check, #2, check, water pressure and cooling systems OK, tachometer reading steady, fuel pressure normal, closed the aircraft type canopy over the cockpit, bring the engines to warm up speed and taxi to position for a wide open run. Now, increasing speed to 50 mph -60-70 -80 and now at the speed range where the previous design started to kite I used the foot throttle over-ride and steering with my left hand, I put my right hand on "Pop" Switzer's stabilizing control lever which operated the elevon (wing tail flap) controlling the last 2 feet of the center section between the twin hulls. At 85 M.P.H. the bow lifted slightly off the horizon - too high for safety, I pushed the lever forward to position 1 ( of 4) and the horizon line returned to normal. Now, at 90 M.P.H. a slight bow lift again, lever to position #2, now the bow was normal in good trim again. Suddenly, at this moment many things seemed to occur. While my 17 pitch (Record props from Switzerland) were turning almost 6,000 R.P.M. my neck snapped back, the Hull lifted off the water about 2-4 inches ... no vibrations from water contact. I felt like I was in a sea plane just after lift off of the water. The R.P.M.'s suddenly dropped back to approximately 5,000, and at the same time the speed increased to the shrill sound of the two engines harmonically balanced. I glanced down at the Keller calibrated speedometer, reading 96-97 -98-99 -100 with those 76 cu. in. 80 H.P. direct reversing engines revving at nearly 7,000 R.P.M. I knew we had just what Mr. Kiekhaefer asked for. Now, almost tranquil from the experience of "The Day I Flew a Boat" with a full boundary layer of air between the hull and the water and seeing houses go by like a picket fence. I realized that the straight away water was fast running out. So, deceleration of the U-6 was started with the same caution used in increasing the speed. The stabilizer control was returned to various positions as the speed was reduced. When the boat speed was between 80 and 85 there was a loud sound and vibration from the hull re-entering the water almost like driving from the highway to a washboard gravel country road. Taxiing to the launching site where all the Switzer Craft crew were on hand for the verdict I could hear all the questions. How did it handle? How fast did it go? What was it like? .....And, you know the answers. The Hull was then returned to the factory for final preparations to be delivered to Mr. Kiekhaefer at Lake X where she was fitted with a pair of 99 cu. in. 100 H.P. engines with stacks and double pinion speedmasters. She went on to reach speeds in excess of 120 M.P.H. This same hull driven by both Johnny Bakos and Dave Craig startled many of the onlookers and the Helicopter pilots that could not keep up with her to allow the photographers to film her, as she won the Gold Coast Marathon from Miami to Palm Beach and return on the inland coastal waters, with a record average speed of 81.78 M.P.H. that may still stand today!

The wings in the pictures all have SSM lowers on them not the XS lowers. The SSM's have the pickup in the front of the bullet rather than rearward as on the XS units. The XS lowers were typically used on a 20 inch transom boat hence the LWP. When positive trim would be used, if the bow could fly, the the angle of attack of the lower was pretty straight parallel to water surface so the intake got water. Trouble starts with lots of trim being used and no bow lifting produced so now the lower unit attack angle produces a vacuum pocket under the bullet which will get back to the pickups as speed increases. Much like blowout happens due to motor being slightly turned to go straight at high speeds countering prop paddle wheel/ tourque produced by larger pitch props. The SSM's were small in diameter and comparatively long which also aided in minimizing blow out at speed.
Anyways, Taco I'll bet the boat won't touch 70, it should be capable of maybe low 60's but, I also think it'll be a challenge to get it to those speeds and not have handling issues. The hull design is at or near its speed limit. Most inlines running upper 60's low 70's are on a hulls having some aero features as well as bottom features helping to lift the boat to reduce wetted area. But hey I can be wrong too.
The clever prop you have will not lift the bow so the Dr is correct, you might have water starvation as the motor is trimmed with minimum bow rise.
You should run a chopper, that will raise the bow..there will be torque steer so make sure your cables are good.
If you have an 850 4 in line XS lower the gearing is different than on the 6 inline, so hard to predict what you need, all my experience is with the 6 cyll ratios.
That said, I have several in line choppers I don't use and have been to busy to bother selling. My guess is a 22 pitch 3 blade chopper would spin just above 6,000 at low 60's. About right for an XS. If that speed is trouble for the boat I have a few early 70's vintage two blade elephant ear choppers that spin up, hold the bow but, run slower due to earlier, not as refined, blade design.
Name and address please I'll send ya a 22 chopper to try, please cover shipping via PayPal once I get shipping sorted out. I want to have good international relations!!!!! Report back after you test, we'll work out a price, it might be free dinner if I find myself in your neighborhood

Hey Robby,
Thanks for the great story about the Switzer Wings. Like Randy says, that are real race boats with all the right components. My boat is just a flat bottom pleasure boat that i want to go fast with. I am not going for the final extra mls/h but I want to see some difference between the Merc 1000 and this motor.

I once owened the 1978 worlds fastest race boat of a German racer named Walther Vieser. I think there was a Merc 1750XS on it with 6 carburaters { see if I can finfd a picture of that boat/motor } The world record was set at 211,437 Kms/h , 132,148 mls/h? I had it a couple of months but was to affraid or scared to put it in the water for a ride so i sold it. I have not the skills to run such kind of boats.

Hey Randy,
Pleased to here from you. You are absolutely right that this boat has it speed limits. It is only 16 ft and about 600 lbs or even less with a very flat but wide bottom.The trim tabs can be set in 5 different positions. I will start with the position that give maximum bow lift and see what will happens. If it turns out that a chopper will perform better I would gladly accept your offer but want to pay for it. If you ever decide to visit the Netherlands/Amsterdam I will invite you to my house and we will have a boat ride. I have some "family " pleasure boats also for nice cruising.

Taco.

picture Vieser boat

motor

I know there SSM's the Wing, I was just pointing out angle of attack and why/maybe the FGS LWPU was designed. Anyway, I did a road trip back Illinois 2006 for a all year high scholl "last blast" picnic and managed to hook up with Bobby Switzer (known him years)and gave me a signed copy Extreme Boats mag the article and pix it was in.

But on props I agree a chopper be much better. I'd take the offer to ship the 22 3B and the 2B big ear. One or the other would work. To bad so far anyway, but can't do much about that. Try on both and what don't work send back with a check for the other kept. Props! I don't care how many ya got, but never the one ya NEED! Isn't boating fun?