where to place smart tabs

great site keep it up<br />if U look at the pic of my 1960 dup-dam with 25 hp ob mariner, where can i place those smart tabs. right now i have a hydrofoil,but i want to test it also with the tabs ,problem is the space<br />i think. or can i take smaller ones so they will fit next to the swim ladder,or is this just no good with my set up and should i stick with the hydro (performance, planning etc is oke,but it can always be better) I hate 2 drill holes to far out because that's where the transom connects to the hull.Availeble space is approx 20 centimeter but i think the width of the tabs are bigger for this type of boat (14.7 ft long)<br />and ofcoz diff. 2 guess,if i use smaller tabs<br />(smaller than recommended for this type of boat)<br />will they still outperform the hydro in my set up<br /><br />thanks for the advice (nautiJohn .... )<br />

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Cant answer you question but love the boat, I like your stern line but isnt storage a bit of a problem.

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yes it is<br />but i live near the water and have an (erm dunno if the word exists) in house/water shelter with lifting capability) so i simply go in my water shed and lift it out and keep it hanging if no work is to be done<br /><br />

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From the picture it looks as if your motor leg is too long?<br /><br />Running the antiventilation plate this deep increase drag, reduce speed, and ruin mpg.<br />Even worse with the fin attached <br /><br />How is your trim angle?

Re: where to place smart tabs

It might be that the pic is somewhat troubling the correct view / as far as i learned here<br />the cav.plate for small boats should be even (height) and parallel (angle) with the hull and so it is . the fin is on top of the water when on plane (so no drag) my concern is ,since it's an old wooden boat, that the fin is pushing the stern upwards, thus creating tear and wear on the wooden transom where it is not build to endure this upward tear and wear,therefore i want to test those tabs,because they lift the hull and not lift the hull by upright powers through the transom ,i figure in those days that they designed my boat the transom was only submitted 2 propell horizontal powers and not lifting powers as well, that's why i want to try tabs<br />so in the long run i do not ruin transom/hull connections (all wood/with copper reinforcements)

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V?X, that is a beautiful boat !!!

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thanks ae708 It took me 2 years to get it all back togehter again in the original way ,the only thing is that according to the so called "experts" this boat can have max 25 / 40 hp on the transom<br />so i took the 25 (2stroke, weight issue) to be on the save side.And it works quitte well .I must say without the hydro it takes too long to get on plane,so I keep it on . but the upward transom power makes me loose some sleep<br /><br />(just for U ae another pic

Re: where to place smart tabs

V?X;<br /><br />Beautiful boat! You should use the ST980-30 Smart Tabs.<br /><br />They are 9 inches wide (about 230mm) It looks as though you have the room on the outside of the swim ladder. They project back from the transom 8 inches (about 203 mm).<br /><br />Try contacting our dealer Harry Bomert Water Sports @ 31-521-361-281 in Beulakerweg 153, Ag Guethoorn, Holland 08355.<br /><br />Also; do not use the foil in conjunction with the Smart Tabs. It will cause handling issues.

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txs Nautijohn .i didn't know the smart tabs were available in that size , will contact harry bomer this weekend.thks

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What a sweet boat!! Now thats something to proud of.<br /><br />Are you sure you cavitaion plate, (the plate your fin is on), is even with the bottom of your boat? Hard to believe that the way it looks is just an illusion.<br /><br />You are correct thinking as you do about the extra force you are putting on your transome. Even though the tabs are going to make a new boat out of it, I think I would hate to be the one drilling 14 holes in that piece of art.

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Wow thats a nice boat! I'm almost finished building a similar type boat myself (a ten foot one).<br />Is that a stainless steel rubbing strip? Where did you get it? I've been trying to find something suitable for mine and its not easy! <br /><br />Lubedude, the plate with the fin on....it is not level with the bottom of the boat. However, the little plate above that one (I don't know what u call it) is level with the keel. Its exactly the same on my boat<br /><br /> http://www.sum-it.biz/squirt/website/

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If that is the case, the engine is very much too low on the transome, regardless of what boat it is.

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Hmm yes it looks like I am wrong too. I've just seen a photo of the same boat and engine as I have and they have the motor raised up a few inches...<br /><br /> http://www.glen-l.com/picboards/picboard10/pic524c.html

Re: where to place smart tabs

With all due respect: If that motor leg is 5" too long, it should be corrected. It may be right, but the pic leaves an impression of too long leg.<br /><br />No matter the boat age and type, the antiventilation plate (with the plastic fin in this case) should level with the keel line. If this, for some reason, returns a problem, a lower fit could be considered. It is, however, much more common to run the motor higher to reduce drag etc.<br /><br />Re. stress on transom: The lower the prop sits, the more stress will end at the transom as the prop thrust will try to lift the bow alone by pushing the lower transom and pulling the transom top. Like a wrench on a bolt.

Re: where to place smart tabs

Thanks for yr replies, i will check again if my cav plate is correct,but (maybe dumb question)<br />the cav plate should be even with the bottom of the hull /i suppose this is what U mean with keel line UU<br />in the pic my trailer is not horizontal and the ob was not yet trimmed right,i did not take a pic after i adjusted 1 or 2 things ,but when on plane the fin is just on top of the water, it should be the right position i guess ,otherwise it should be still underwater or extremely above <br /><br />Rudderman it's indeed a stainless steel rubbing strip but i got it of an 1962 riva<br /><br />they do still sell it though at http://www.boesch-riva.nl/default.asp?id=9&ACT=5&content=41&mnu=1 <br /><br />but they are second hand<br />love yr project <br /><br /><br />I think i will remodulate the tabs, and reinforce the connecting part to the transom with stainlees steel and than only use 2 or 3 screws more to the direction of the ladder, i suppose it will hold due to the stainless steel reinforcement or i will glue a sort of strip on the transom on which the tabs connect. <br />i don't supose an extra inch outwards for the tabs would do much harm (might even be better since they lenghten the hull..<br /><br />haven't figured it all out yet, but i'll take pics when i'm done<br /><br />txs for yr comments<br />V?X<br /><br />(edit in this low quality pic U might see better that the cav plate is even with the hull or do U recommend to raise it anyway an inch or ..)<br /><br /><br />

Re: where to place smart tabs

Sorry for being pushy - on this pic the level seems pretty alright.<br /><br />It's common to raise the motor to reduce drag but my first action would be to remove the fin. Then play with trim idea...<br /><br />By keel line I mean the prolonged line of the lowest part of the hull - in case of no actual keel, it's the hull bottom. Many designs with a rather flat bottom have a keel that flattens out as it approaches the transom because a keel just in front of the prop disturbs the water and make the prop less efficient.<br /><br />BTW: Years ago a friend had similar design, made from GRP. It had a Johnson V4 (75 hp?) and when going at wot, it refused to turn properly! Turning the wheel simply made the boat turn slightly and then go on in the same direction - sideways! Pretty dangerous when it eventually caught a wave and snapped into the new direction!

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heres my 2 cents, dont do it.... take off that fin and throw it far away. your boat is a great looking old classic... leave it !!! <br /><br />its just me though, my opinion

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V?X, <br />Thanks for the link. I emailed them in Dutch using a computer translator so I hope they can understand it!!

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Rudderman if u need assitance lemmeknow<br /><br />Update<br /><br />i went to the dealer , and saw the smart tabs,<br />(must say the helpfullness of those people were pretty much the same as the temp on an average day on the north pole,where polarbears are having a party but people tend to fade away,guess that's typical dutch to much trouble without sufficient fee)<br /><br />anyway i decided not to take them or the smaller ones,reason for this is that they adviced me that in order to work properly, the tabs must be connected to the transom with all screws otherwise they will eventually come loose<br />(makes sense ofcoz due to pressure and all)<br />but i do not want to put a screw trough my transom and side hull connection. ,they gave me the advice that tabs are not designed for older boats so i should not bother, ofcoz i know better<br />old,new,wood,fiber, tabs will do them all good i suppose my set up is no good , but i'll hate to loose the swim ladder,because it was originally on the boat for the skiers to get in<br /><br />anyway maybe i'll come up with an similar idea of my own using only the actuaters of the smart tabs but with a different plate connection design for old woodenboats with not 2 much space<br />(i figure as long as the tabs are in the right spot,and have the right dimensions and angle to the hull,the connection of the tab does'nt really matter as long as the actuater is fitted in the right position) see rough pic <br /><br /> thanks fr yr input<br /><br />(no patent yet nautijohn <br />Greetz<br />V?X

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V?X<br /><br />I am very sorry that you did not get the advice or correct information from the Dealer. Unfortunately we can not controll the information these people provide even in this country (USA) let alone arround the world.<br /><br />I am not sure how you would like to attach the trim tabs to the boat, but i understand your desire to keep it as origional as possible. If there is anything I could do please do not hesitate to contact me through our web site John@Nauticusinc.com However, if it were my boat I would not put anything on it (permanently) that was not orgional deign. In Fact, I would not even put it in water that was not perfectly clean. Great looking boat!