It looks like your drives are mounted about 2" lower than mine. When you say the boat "pitches" do you mean the bow goes up and down or does the boat rolls side to side? I assume you mean the bow goes up and down ( porpoise) since you were adding weight in the bow. I'm not sure why having the drives too deep would cause the boat to porpoise but there are some things you could try. My boat handles much better with the propellers turning inward instead of outward like yours are now. The bravo drive can spin in either direction so you can simply switch the propellers and run the boat in reverse. (what kind of throttle do you have? single lever or separate shift/throttle) The only way to raise your drive height would be to change the lower unit to a "shorty" which would raise the propeller shaft 2" in relation to the bottom of the boat (x- dimention) This would be expensive but with the x-dim raised you could try a 4 blade propeller or again turning the propellers inward. You have Mirage Plus propellers now? Were they modified?

- M

I'm sorry for my english..yes bow goes up and down..
I have separated shift throttle and mirage plus not modified..
Thank you!!!....
I'm very pleased to welcome your advise that will help me to solve

Hi for what my opinion is worth my believe is that the centre of gravity is too far aft and for what ever reason the thrust line is not driving the bow down.

I think that your first plan is correct and I would place sacks of filled with sand in the bow in order to move the C of G forward.

Once you have the C of G in the correct place for the hull you can then use the trim to lift the bow and make it hang out there if you so wish.

Another thought have you checked the bottom of the hull for straightness, does it have a hook in it aft where it has sat on a frame for years with big block

motors unsupported aft ? It is worth a look ! run a straight edge from the transom forward and see if there is any gap along the hull or rails.

Personally I would start with about 100 Kg of sand in sacks as far forward in the bottom of the hull as you can go, if the problem is reduced but not perfect add another 25 Kg,

and so on, you can always remove it if the bow rides too low and you cannot trim it out to suit what you want by way of a ride angle.

Equally I tried a set of well known aftermarket 4 blade propellers on my Magnum 27 and they gave me so much stern lift forcing the bow down at speed that I had them

reworked to reduce the lift aft, after changing my trousers that is.

Weight forward first then see how it rides, again only my opinion ( but I have been doing this for over 50+ years) so please give it a go !!!!

Kalaazar

I put sandbags under the bow at the beginning of 100 kg and then other 50 kg and handling has improved
Thi despite,use flaps to keep the bow down and with full fuel tanks too
I really appreciate your advice
Gio

Gio, I have been thinking about your trim problem again. Are you sure that your power trim is fully retracting on both drives ? Check the overall stroke length.
If you are happy that is all ok and the drive are going fully under I would load a further 100kg of sand in the bow just to see if you can achieve the trim stability which you are looking for, you can always take it out again or at least some of it if you need to.
If that works and you are happy then leave it there. It would be a lot less money than the next step of custom props to lift the stern.
Good luck
Ian Toll

Hi Ian
Thank you for your kindly interest about my handling problem
Power trim works well and the boat after reaching 50 mph needs to up the bow
You undertand my problem is more to lower speed,of course
Yesterday broke a sand bag,I have to find a better way to secure it under the bow
I will appriciate all your next advises
Gio

Hi Gio,
I assume that you are using the old style Jute Hessian fabric sacks and not plastic ? Double bag the sacks to give your self a better chance until you can identify just how much weight is needed to provide the low speed trim with the drives fully in and keep loading in the sand bags well forward if required.
Then please let us all know how your boat handles with the change in the centre of gravity.
Ian