Rib Tender won’t plane two up

[BruceK]

yes but a finer pitch prop would still be a boon not a negative.


EDIT i.e. if you had said it's possible his prop is too coarse then your argument makes sense. If the OP puts on a finer pitch but now only reaches say 18 knts but can plane 2 up that would be a equitable solution. However I have seen some smaller (280 size) rather heavy ribs (Avon GRP hull) that takes 4 to lift plane two up with a modified 10 on the back so I really struggle to see this being a lack of hp. Not just 2 up but used to tow kneeboards and the like as well

 

[atol]

yes but a finer pitch prop would still be a boon not a negative.


EDIT i.e. if you had said it's possible his prop is too coarse then your argument makes sense. If the OP puts on a finer pitch but now only reaches say 18 knts but can plane 2 up that would be a equitable solution. However I have seen some smaller (280 size) rather heavy ribs (Avon GRP hull) that takes 4 to lift plane two up with a modified 10 on the back so I really struggle to see this being a lack of hp. Not just 2 up but used to tow kneeboards and the like as well

it would be usefull if the op let us know what the max rated HP and dry weight is for the rib from the inspection plate or model details
lots of different flavor of ribs these days,a sitdown with a consol sounds quite heavy.
for example the highfield center consol3.4m is 173kg dry,a 25 hp is recomended but will take up to 30 hp
Classic 340 Deluxe - Highfield Boats

 

[girlofwight]

Her/hers....

Its a Grand 330l.
GRAND | Silver Line S300L, S330L

Dry weight 85kg, engine 55kg, so 140kg before fuel and odds and ends. Depending which set of specs you read, rating is 15hp to 25hp, so 20hp is in the middle.

Its being lifted for a scrub and fitting a foil tomorrow, see how that changes things. There is a rev counter, so another avenue to pursue if there are still problems.

Moving weight forward as in crew is a possibility but I have a slightly nervous crew - bad rib experience in the past - and the aft seat is more supportive with back rest etc.

Thanks for the various thoughts.

 

[northwind]

Her/hers....

Its a Grand 330l.
GRAND | Silver Line S300L, S330L

Dry weight 85kg, engine 55kg, so 140kg before fuel and odds and ends. Depending which set of specs you read, rating is 15hp to 25hp, so 20hp is in the middle.

Its being lifted for a scrub and fitting a foil tomorrow, see how that changes things. There is a rev counter, so another avenue to pursue if there are still problems.

Moving weight forward as in crew is a possibility but I have a slightly nervous crew - bad rib experience in the past - and the aft seat is more supportive with back rest etc.

Thanks for the various thoughts.

Can you move the fuel tank to the bow? - it looks to be very rear end heavy. We used to get under powered seariders (4m boat 25hp engine) on the plane by shifting stuff forward, ideally crew once its over the hump they can then sit down. even both of you leaning over the wheel forward would help.

 

[Ferris]

Fuel positioning as has been said but also could the passenger sit on the forward seat facing backwards and shuffle aft one the boat was on the plane.

still puzzling as that boat should plane out of the box.Did anyone mention outboard height? Is the cavitation plate in line or slightly above the keel?

 

[julians]

.Did anyone mention outboard height? Is the cavitation plate in line or slightly above the keel?

yep - first reply

 

[Homer J]

I think you should ask the manufacturer. The advert clearly shows the boat planing with a 20hp and two up. If it can’t manage this I would suggest you have been mislead / mis-sold.

 

[Don107]

Why don’t you get someone else who is not afraid to move around the boat to go for a run with you to see if moving forward will do the trick and if that is the issue you can then try moving stuff around to overcome the. problem

Regards Don

 

[colhel]

Would the outboard need a bit of running in?

 

[girlofwight]

Would the outboard need a bit of running in?

Good point - she was ex demonstrator with 10 hours and first service, so hopefully all covered. However despite that the water pump failed as soon as I got her afloat (and credit to dealer, they sorted it out quickly)

 

[girlofwight]

Why don’t you get someone else who is not afraid to move around the boat to go for a run with you to see if moving forward will do the trick and if that is the issue you can then try moving stuff around to overcome the. problem

Regards Don

Thats a good idea, and not one I’d thought of.

thx

 

[girlofwight]

I think you should ask the manufacturer. The advert clearly shows the boat planing with a 20hp and two up. If it can’t manage this I would suggest you have been mislead / mis-sold.

In touch with the dealer, and they are being helpful. I’m just trying to gather wider views.

 

[Don107]

Thats a good idea, and not one I’d thought of.

thx

It shouldn’t be too hard to get someone even a complete stranger to go for a ride in a rib and it will cost you nothing unlike playing with different props and foils

Regards Don

 

[colhel]

We're over for a week from next Friday, happy to be ballast.

 

[girlofwight]

Right, picking this up.

On dealers advice - and no complaint about dealer, they are helpful - I had a foil fitted and had her hauled for a scrub off - that was third week July. Took her out myself a couple of times, all ok, then I was out of action for a few weeks convalescing after some surgery early August.

Back out this week, two up, and again wouldn't get to plane, although with weight of crew moved forward it felt like, with time, it may get there - certainly I edged 10kn which is more than hull speed. However I was on a quiet bit of river with a 4kn limit so didn't want my test to be too elongated.

Took her out on davits today, and this is what greeted me. Eek! The advice I had was not to have the tubes A/F but, I think, they need it if she is to stay afloat. Where she is only 3.3m I think the problem is, compared to larger ribs, the tubes sit in the water when she is empty.

Winter project - restoring tubes!

 

[jrudge]

They need putting back in the water and jet washing immediatly it comes out or it will turn to concrete.

ribstore rib cleaner is amazing stuff.

 

[Jamie Dundee]

If you have the room something like a small Tetradock would keep things clean.

 

[PCUK]

Just put the crew in the bow and you will be fine!

 

[girlofwight]

If you have the room something like a small Tetradock would keep things clean.

Alas no, as moored alongside mother ship in a Marina bay. The through had crossed my mind.

 

[girlofwight]

Just put the crew in the bow and you will be fine!

Tried crew as far forward as possible, and no, didn’t get there...