25HP motor.... what size boat???

[steve jones]

evening all.

i am looking to get myself a SIB. i currently have a small fishing boat (reiver) but where i have it takes two of us to get it in the water ( taking from boat yard with tractor over beach etc... you know how it goes) for this i have a 25hp mercury which i want to utilise for a SIB.

what would you guy recommend as a minimum size/floor SIB to allow me to safely utilise the 25HP?

most i have looked at under 4m say 20hp max. is this a arse covering from the manufacturers. do any of you run a 25 hp on the likes of a honwave 38ie?

would yous recommend an ali deck over a air deck?

[Limecc]

Originally Posted by steve jones

what would you guy recommend as a minimum size/floor SIB to allow me to safely utilise the 25HP?

You don't say if it's an older 2 stroke or newer 4 stroke. 4 strokes gain a third cylinder and weight penalty at this hp.

You may not find this helpful but the manufacturers state the maximum safe horsepower for a reason. Some have overpowered their SIB's/RIB's but you're on dodgy ground regarding insurance and will have an unbalanced stern heavy boat that can bite you unexpectedly.

Overpowering a 20hp transom by 5hp is a 25% increase and obviously more critical than if you were overpowering a 50hp transom where it would only be 10% over.

The aluminium floor will be better to avoid the rippling floor effect, be prepared for the extra weight and setup time regardless of what engine you use, many with this weight craft decided to trailer the boat. Also ~65kg engine weight IMHO is beyond safe lifting by one person. 20hp/45kg is hernia inducing.

https://www.youtube.com/watch?v=lDcX...ature=youtu.be

[pumpkinking]

Originally Posted by steve jones

evening all.



i am looking to get myself a SIB. i currently have a small fishing boat (reiver) but where i have it takes two of us to get it in the water ( taking from boat yard with tractor over beach etc... you know how it goes) for this i have a 25hp mercury which i want to utilise for a SIB.



what would you guy recommend as a minimum size/floor SIB to allow me to safely utilise the 25HP?



most i have looked at under 4m say 20hp max. is this a arse covering from the manufacturers. do any of you run a 25 hp on the likes of a honwave 38ie?



would yous recommend an ali deck over a air deck?

With the used outboard motor market the way it is, it strikes me that you could sell your 25 and get a brand new or nearly new 20, if that was what you wanted.

[jeffstevens763@g]

I run a 25h on my excel 435 copes with ease

[TmMorris]

Is your thinking to end up with a boat that you can hand launch and set up so as to avoid the tractor? If so then you might find you still need two people as your 25 could be quite heavy?

[treerat]

I used to run a Yam 3.83 with a 25 hp on the back. Great fun and just inside the manufacturers limit.......

[Alsgontrvln]

Hi, I bought a used Avon 4.0Spitfire RIB, Size 4 Meters long, or 13.3 feet. It had a max rating of 25 hp. Now I'm not sure if that is for 4 cycle but definitely 2 cycle when talking about weight of the motor. AS 4 cycles are of course heavier. Hope that helps a bit ?

[steve jones]

Originally Posted by Limecc

You don't say if it's an older 2 stroke or newer 4 stroke. 4 strokes gain a third cylinder and weight penalty at this hp.

You may not find this helpful but the manufacturers state the maximum safe horsepower for a reason. Some have overpowered their SIB's/RIB's but you're on dodgy ground regarding insurance and will have an unbalanced stern heavy boat that can bite you unexpectedly.

Overpowering a 20hp transom by 5hp is a 25% increase and obviously more critical than if you were overpowering a 50hp transom where it would only be 10% over.

The aluminium floor will be better to avoid the rippling floor effect, be prepared for the extra weight and setup time regardless of what engine you use, many with this weight craft decided to trailer the boat. Also ~65kg engine weight IMHO is beyond safe lifting by one person. 20hp/45kg is hernia inducing.

its a 1990s 25hp 2 stroke. i would be looking to trailer it if i went for an ali deck

thanks for the overpowering bit. makes sense when its said like that... 25% is alot

[steve jones]

Originally Posted by pumpkinking

With the used outboard motor market the way it is, it strikes me that you could sell your 25 and get a brand new or nearly new 20, if that was what you wanted.

only issue is the engine i have i am halfs with a pal. so selling wont be an option as still need the 25hp for other boat

[Steve509926]

You don't say if your 25hp is a short or long shaft.
If it's a long shaft I think you will struggle finding a suitable SIB.

[Fenlander]

>>>where i have it takes two of us to get it in the water ( taking from boat yard with tractor over beach etc... you know how it goes) for this i have a 25hp mercury which i want to utilise for a SIB.

Hi and welcome to the forum.

You may well find by the time you've found a size of SIB that takes a 25hp added to the weight of the 25hp and 25l of fuel in a tank plus kit then that too will be a two man job to launch.

[steve jones]

Originally Posted by Steve509926

You don't say if your 25hp is a short or long shaft.
If it's a long shaft I think you will struggle finding a suitable SIB.

I have both but the one going on sib will be short shaft

[steve jones]

Originally Posted by Fenlander

>>>where i have it takes two of us to get it in the water ( taking from boat yard with tractor over beach etc... you know how it goes) for this i have a 25hp mercury which i want to utilise for a SIB.

Hi and welcome to the forum.

You may well find by the time you've found a size of SIB that takes a 25hp added to the weight of the 25hp and 25l of fuel in a tank plus kit then that too will be a two man job to launch.

I hear you. I will be looking to trailer it. So hopedully that will make it managable for 1 person

[Steve509926]

A couple of suggestions :-

Excel Volaire 390

Excel Vangaurd XHD395

[jeffstevens763@g]

Originally Posted by steve jones

I have both but the one going on sib will be short shaft

Just for info some manufacturers at around 4m go to long shaft excel still go short on the 435 vanguard. usually when tube dia is at 500mm they go long shaft but excel are short shaft.

[Limecc]

These guys have overpowered their Ribs, the 3.5m/40hp is chine walking doing 35kn one-up flat out and the 3.7m Grand (max 30hp) which has a 50hp Honda is a few knots faster nearer 40kn.

https://www.youtube.com/watch?v=hnuLfZ8lgZU

[hinckley_steve]

If I were you I’d also consider the F-Ribs if using this engine. They are more money but will perhaps handle the extra hp, and make for a more rigid performer.

They are also portable/fold up for storage/transportation, would be ok on a trailer, and yet still light enough for launching wheels etc.

It’s just a thought… have a look. I think their website is F-RIB | Revolutionary new Foldable RIBs (F-RIBs)

[Steve509926]

Originally Posted by Limecc

These guys have overpowered their Ribs, the 3.5m/40hp is chine walking doing 35kn one-up flat out and the 3.7m Grand (max 30hp) which has a 50hp Honda is a few knots faster nearer 40kn.

"what would you guy recommend as a minimum size/floor SIB to allow me to safely utilise the 25HP?"

A serious question deserves a serious answer.

[Limecc]

Originally Posted by Steve509926

"what would you guy recommend as a minimum size/floor SIB to allow me to safely utilise the 25HP?"

A serious question deserves a serious answer.

I've said already. I don't recommend going over the manufacturer's rating. There's no definite answer if you are going to do it anyway, the bigger the safer, something like a heavy T40.

[Steve509926]

Originally Posted by Limecc

I've said already. I don't recommend going over the manufacturers rating. If you are going to do it anyway, then the bigger the safer, something like a heavy T40.