Seamax Return.-

Sea Rider

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Sep 20, 2008
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After masking side tubes, transom plates, painted both sides with black matte aerosol paint, 3 coats one after the other were applied with enough time for each paint coat to dry well. The finish is even..

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Once dried, installed on transom two heavy duty front & rear metal plates, the original which were plastic ones were quite thin, flexible and crappy looking.

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On friday will do a water test to check max wot rpm achieved with 2 up before going for a prop maximization which would be the ideal complement for this impeccable work.

Would advise to stay away from inflatables that have installed water gate on lower transom, their out flow rate is extremely slow. Much better are traditional plug type.

Happy Boating
 
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Sea Rider

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Sep 20, 2008
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On a water trail with slight wavy and windy cond with 2 up sitting way aft, combo which weights around 400 Kg achieved 37.5 Km/h at 4700 wot rpm. Sib was top inflated to 3.0 PSI for best overall rigidity. At 3/4 throttle the boat literally jumps onto full plane under 4 seconds, no need to balance our weights forward which is a plus.

Water flow at speed is passing right under upper small water deflector plate which is the sweet lower leg/transom ideal height, Close turns are superb with no prop aeration whatsoever. There's a some water splashing side of water deflector plate due to rear hull hook, v shaped lower transom and rear alum floor panel flexing which doesn't affect performance.

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Rear leg middle wake is completely flat, an ant couldn't surf there LOL!!

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Next step, maximizing a 11 pitch 3 blade OEM prop to pull wot revs towards max 5800 rpm range from current 4700 max rpm achieved during test.

Happy Boating
 
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Sea Rider

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It's been a tough work dialing sweet lower leg/transom height due to Sib having too may factory flaws. Check the difference in lower leg heights before as when taken out of the box and after modifying (chopping down) transom height.

Before : Wate flow was passing on top of Anticav Plate at plane.

Before.JPG

After Transom Modification : Right under small upper water deflector plate.

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That's the Sweet Lower Leg/Transom height for any modern OB....

Happy Boating
 

Sea Rider

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Sep 20, 2008
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New OEM 11 pitch prop just arrived, should be installed by weekend.

11 Pitch Prop.JPG


With OEM 13 pitch OB was achieveing 4800 wot rpm/ 35 Km/H with 2 up on flat calm no wind water cond. Will post max wot rpm/speed/11 pitch results. I have no doubt that the performance difference will be oustanding...

Happy Boating
 

alanfox55

Chief Petty Officer
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Nov 17, 2011
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476
Congratulation Sea Rider hope it works for you as good as it looks.
 

Sea Rider

Supreme Mariner
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Thanks Alan,

Tomarrow early in the morning it's D day, will post results...

Happy Boating
 

Sea Rider

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I'm beginning to think that combo is somewhat cursed, first was the SiB with full tech flaws, now the tach & OB. To make the long story short.

Owner swapped factory delivered OEM 13 pitch prop for same OEM 11 pitch prop. Installed new prop, went to test it. The difference found is quite outstanding, better hole shot with added weight. At wot tach froze at 4800 wot rpm, but reads well idle to 3/4 throttle. So didn't know how much wot rpm OB gained running a 2 less pitch prop.

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During trial strange grounding like sounds were herd at lower leg, when prop was removed some damage was found at rear prop and prop housing, the prop was spinning right against housing, idiotic prop seller didn't advise that a prop spacer was needed to lock prop onto shaft. What happens is that when prop spins at high thrust, prop is pushed hard inwards against housing wearing the edge at both sides.

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Check upper lip prop damage between old and new prop...quite height difference.

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What find strange to say is that both are Tohatsu OEM props, while the 13 had a bronce spacer fitted on hub, the new one didn't,. Owner assumed right that it was just a matter of swapping one for the other, which proved not. Seller should have said that the 11 pitch needed a prop spacer, the plastic bag in which prop was packed, didn't have a warning note specifying a spacer. As it's seller's fault will let him know what happened to send me another new one at his cost...

So a new 11 pitch prop, spacer and tach are about to be ordered.....stay tuned.

Not Happy Boating
 

NightAngler

Cadet
Joined
Jan 2, 2016
Messages
16
Same length, color and make as mine. Had to raise the transom 2 inches. Great boat..bought in 2011 from Vancouver (Richmond) and shipped to Ontario as liked the bigger tubes. No problems with it at all. The engine (2005 Merc 9.9) however has an odd lower unit design, back spraying like crazy. Easy fix. I really like my SEAMAX 380. From twin 283 inboards old Chris Craft to a Bayliner In/Out..and a couple Outboard 16 footers..but I must admit this simple little boat and engine I love most for simplicity.
 

Sea Rider

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Sep 20, 2008
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NA,

As you have experienced it's not just a matter to sit an OB on transom as one would imagine and expect top water performance. OB could have back, over transom water splashes that will slow combo down, even prop aeration if OB sits way high. Tohatsu and rebadged brands have bit larger lower leg heights compared to other brands and most of the time the boat whichever type it is needs a transom height optimization if wanting boating perfection with a under powered OB. Is that 9.9 a 2-4 strokes OB ?

Happy Boating
 

av8or091

Recruit
Joined
Jul 7, 2017
Messages
1
Seamax Ocean Pro 430T

I have a new E-TEC 25 bolted up to my RIB and have just begun to learn the nuances / intricacies of the setup. Was out on Wabamun Park lake this last week to see what she can do.

Quite a beast gets up on step quickly and without issues.
 

Sea Rider

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Sep 20, 2008
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A Rib with well matched OB height onto transom will have a better hole shot, faster plane compared to any Sib of same size. A Rigid Hull compared to an inflatable one flexes more and attains more hull drag to overcome faster.

New tach along missing prop thrust washer has finally arrived, will check shorty if hopefully runs towards the max wot rpm range with 2 up.

Happy Boating
 
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Sea Rider

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Updates :

Installed damaged 11 prop onto prop shaft along missing thrust washer, prop has 8 mm clearance between rear prop body and prop housing, can see the washer right in middle clearance.

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Was afraid prop would aerate badly at full throttle due to excessive exhaust coming out through front prop, to my surprise nothing happened. With 11 prop Sib has gained a faster hole shot than before, makes impeccable tight turns at speed.. OB now revs full throttle to 5900 with 2 up. You can't possibly ask for more..

Happy Boating
 
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Sea Rider

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Sep 20, 2008
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Transom's Waterloo Time.-

This Sib has 3 years of near constant use, was making too much water at rear lower deck which water drain valve did not managed to remove when bow was skyrocketing with opened valve. Decided to take it to marina for terra firme close visual inspection. When all alum panel floorboards were removed, too much water was found sitting at lower transom, lower fabric was found partially unglued, so decided to unglue with a heat gun the remaining fabric portion.


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Holly Molly, this is what was found..

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External transom fabric was found about same, had to be completely peeled off to expose the lower transom for a close look.

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Front and rear sheets of the transom sandwich were found partially unglued, rotten and severely water soaked. The factory employees forgot to fiberglass the lower transom to seal it well against water intrusion as did on the upper transom. Who understands these PRCH idiots. Seems a buy another new Sib soon sales issue ?

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To rebuilt same transom to work as it should will be a long process and too pricey, so plan to install a new Zodiac brand transom of superior quality along a RIb water drain valve which drains water much faster as doesn't have a rear diaphragm to deal with that slows drain operation.

Happy Boating
 

Sea Rider

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This low hours Zodiac Zoom transom removed from a 4 Meter Sib that had a fiberglass hull installed will be used to replace the original Seamax one. Has the same exact measurements, original transom side holders will be used, much faster and cheaper work is to swap the donor wooden transom alone and install it inside both side reinforced glued holders.

Incredibly, this Zodiac transom was factory delivered with the lower play sheets highly exposed as last one, no wonder tech plate states being PRCH manufactured. Will inevitably develop same transom rottenness issue when water intrusion makes its way into lower transom and soaks it continually. To avoid this factory flaw lower transom will be epoxy sealed before being installed.

Click image for larger version  Name:	Transom Modification.JPG Views:	1 Size:	196.5 KB ID:	10637779

This bizarre V shaped transom was holding too much water from red line to V lower transom when combo was at work, will cut the entire yellow portion seen on pic and re shape it to a less deep V shape. Jurassic style drain valve hole will be sealed and a fast flow Rib drain valve sitting the lowest possible will be installed.

Happy Boating
 
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