New to boating with a new second hand RIB looking for advice

Franburger · 21 April 2020, 15:12

I recently just bought this custome made fiber glass "rib". Im going to be using it for close to shore fisihing, i stupidly bough a long shaft 25hp engine for it after fitting it i realised I probs should of got a short shaft. Im thinging of raising the transom. Does anyone have any suggestions on the best affordable way tondo this. Also i live in the Seychelles so order specific products can be expesive and timley, im looking for a more of a DIY job : )

jeffstevens763@g · 21 April 2020, 15:56

hello mate welcome when the engine is down how far below the keel is the cavitation plate

Franburger · 21 April 2020, 16:46

Thanks Jeff, the cavitation plate sits around 5"ish below the keel, when trying to turn it feels pretty heavy. Do you think being so low would cause the front to lift we accelerating?

Thanks

Pikey Dave · 21 April 2020, 17:38

Quote:

Originally Posted by Franburger

Thanks Jeff, the cavitation plate sits around 5"ish below the keel, when trying to turn it feels pretty heavy. Do you think being so low would cause the front to lift we accelerating?

Thanks

Way too low, that’s the wrong length engine for that boat.

Franburger · 21 April 2020, 18:01

Yeah sure is, sadly i cant return the engine to the shop as its been used, so ny only option is to raise the transome. Any thoughts on the bestbway to do this?

Unknown · 21 April 2020, 18:01

Do you think you can raise the transom 5”? If not, best to look at another engine.

Franburger · 21 April 2020, 18:09

Quote:

Originally Posted by Unknown

Do you think you can raise the transom 5”? If not, best to look at another engine.

I think I can!! where the engine sits the transom dips down by 2" so by leveling out the transom and then adding 3ish inches i should be good. The question is whats the best way of doing it. Wood and fiber glass, metal bar across the transome??

Unknown · 21 April 2020, 19:53

Looking at the transom, it looks like it’s flush with the top of the tubes already. I’m not sure if raising the overall height is a good thing or not. People raise them in various ways, fibreglassing is the best way though.

jeffstevens763@g · 21 April 2020, 21:03

Yep short shaft transom 15 inch long shaft engine 20 inch long now if you have to keep the engine I would have a jacking plate around £250 on the other hand if I lived in the seashells I would accept any length of engine go slow and enjoy

beerbelly · 22 April 2020, 05:51

I have an xl outboard on my humber destroyer I have bought these haven't been able to fit them yet with the lockdown but should do the job
https://www.ebay.co.uk/itm/CMC-Stati...72.m2749.l2649

Franburger · 22 April 2020, 07:40

Yeah decent this is the kinda thing im looking for, Thanks!! I'm thinking It will have to be a DIY job as theres no ebay out here lol I will let you know how I get on : )

Franburger · 22 April 2020, 07:42

Slows not an option lol I've just looked into jacking plates and it seems like a uch better option and raising the entire transom, Thanks!!

charliee · 22 April 2020, 10:04

I see 3 options
1. New Boat
2. New engine
3. Some form of Jack Plate
Good Luck - wish I was in the Seychelles!

Franburger · 22 April 2020, 10:29

Hahaha im going for option 3, fingers crossed.

samt · 22 April 2020, 11:22

Converting to a shortshaft might be another option... you'd need to switch the drive shaft out for a short, new water tube and then a driveshaft housing. Not difficult to do on these, just depends on avaliability of parts.

Franburger · 22 April 2020, 12:21

Quote:

Originally Posted by samt

Converting to a shortshaft might be another option... you'd need to switch the drive shaft out for a short, new water tube and then a driveshaft housing. Not difficult to do on these, just depends on avaliability of parts.

Thanks Sam, I'll deff look into this if the DIY jack plate doesnt work! Sounds cheaper than replacing the boat or whole engine

andrew_ireland · 27 April 2020, 14:23

Definitely go with a fixed jack plate with minimum setback. Much better than messing with the transom itself

Franburger · 27 April 2020, 16:46

Thanks Andrew, yeah jack plate looks like the best option, when lockdown ends on the 4th over here its my.first job

Locozodiac · 27 April 2020, 22:38

Some Issues :

How tall is the transom measured in straight line from transom's center to the Rib's bottom hull ? If it's 50-53 centimeter tall needs a Long Shaft Motor..

If the lower leg is too long, the motor should experience small to medium water splashes at back transom, the deeper the more it will shower as in pic. Test at wide open throttle with motor previously trimed to 90 deg, perpendicular to water level. Probably only needs a motor/transom height fine tuning for water flow at speed to skim right under the upper splash plate which is the ideal lower leg height for any motor with tall horizontal lower leg plates distance such as Tohatsu and their rebranded versions.

If need to raise the motor, these are excellent choices to avoid rising and fiberglassing the transom to its new height.

Happy Boating

Locozodiac · 01 May 2020, 00:24

If you don't want to go for a transom height modification nor install a motor mount or a rear jack plate as previous posted pics. You need to go for a wot run with deck load well balanced, motor trimmed to 90 deg (fully vertical on transom) and check how much water intrusion is the lower leg producing at front leg. Apart from the shower the combo will be slowed down as there will be too much water leg drag exerted against the lower leg's front.

Check link for plain understanding how the splash was totally solved. If having any tech question just ask, that's what this nice forum is for...

https://www.rib.net/forum/f36/outboa...tml#post811362

Having a L Tohatsu motor could duplicate it, it's peanuts cost and works as a charm...

Happy Boating